Life assessment of rubber articles in fuels642457/FULLTEXT01.pdfLife assessment of rubber articles in fuels Emmy Selldén The choice of rubber material for use in sealings and hoses

Examensarbete 30 hpJuni 2013

Life assessment of rubber articles in fuels

Emmy Selldén

Teknisk- naturvetenskaplig fakultet UTH-enheten Besöksadress: Ångströmlaboratoriet Lägerhyddsvägen 1 Hus 4, Plan 0 Postadress: Box 536 751 21 Uppsala Telefon: 018 – 471 30 03 Telefax: 018 – 471 30 00 Hemsida: http://www.teknat.uu.se/student

Abstract

Life assessment of rubber articles in fuels

Emmy Selldén

The choice of rubber material for use in sealings and hoses in the fuel system is ofgreat importance. If a wrong type of rubber is used, premature failure during servicemay occur. This impacts the environmental performance, the safety during driving,uptime and economy of the transport. In this diploma work, rubbers for use in sealingand hoses in the fuel system have been evaluated to assess which materials have thepotential to be used under long-term use in contact with commercial fuels.

Three commercial fuel hoses, nitrile rubber (NBR), hydrogenated nitrile rubber(HNBR), ethylene-acrylic rubber (AEM) and fluorocarbon rubber (FKM) of varyingtypes and compositions have been evaluated in diesel with 7% RME (rapeseed methylester), 100% biodiesel of RME and ethanol fuel. Tests were performed by immersingthe materials in fuel and measure the compression set and changes in properties likevolume, hardness, tensile strength and elongation at break.

The results showed that one NBR material, one AEM and all FKM are potentialmaterials for long term use in diesel with 7% RME. All types of NBR and two types ofFKM (terpolymers, peroxide cured) may be used in ethanol fuel. NBR and HNBRwere the only rubbers evaluated in biodiesel. NBR and HNBR with an ACN contentof ~30% might be used in 100% RME at lower temperatures for shorter periods. Theaging resistance in air was good for HNBR, AEM and FKM but poor for NBR.

Sponsor: Scania CV ABISSN: 1650-8297, UPTEC K 13012Examinator: Karin LarssonÄmnesgranskare: Jöns HilbornHandledare: Maria Conde

I

Svensk sammanfattning (Swedish summary)

I lastbilens och bussens bränslesystem finns det packningar, tätningar och slangar av

gummimaterial. Gummi är ett material som består av så kallade polymerer, d.v.s. långa

kedjor mer repeterande enheter, som är sammanbundna till varandra i vissa

gemensamma punkter. Typ av polymer som används, men också andra tillsatser i

gummit, påverkar gummits egenskaper. Vissa typer lämpar sig bättre när det är kallt,

andra när det är mycket varmt. En del klarar av att användas i kontakt med kemikalier

medans andra bryts ned.

I bränslesystemet kommer gummit i kontakt med bränsle vilket gör att det är viktigt att

det gummit man använder klarar av att användas i bränslet. Ett felaktigt materialval kan

innebära att komponenten drabbas av förtidigt mekaniskt brott vilket medför en

säkerhetsrisk och innebär att fordonet inte kan köras lika länge som tänkt, vilket också

påverkar ekonomin.

I takt med att koldioxidutsläppen ökar och tillgången på olja minskar, utvecklas nya

bränslealternativ till diesel. Två sådana alternativ är biodiesel och etanol. Biodiesel

utvinns från växtolja och fett medans etanol kan utvinnas ur socker, stärkelse och

cellulosa från växter. Att byta från ett bränsle till ett annat innebär dock problem när det

kommer till materialval. Skillnader i kemisk sammansättning hos de olika bränslena gör

att gummit påverkas olika beroende på bränsle.

I det här examensarbetet har tester av ett antal gummi utförts i olika sorters bränsle för

att göra en bedömning av vilka sorters gummi lämpar sig för användning under lång tid i

tunga fordon. Det har gjorts genom att sänka ner prover i olika bränslen vid förhöjda

temperaturer. En förhöjd temperatur gör att kemiska reaktioner, såsom åldring och

absorption av media, går snabbare, vilket gör att man på några veckor vid en hög

temperatur kan uppskatta bränslets påverkan under en lång tid vid lägre temperatur.

Eftersom att gummikomponenterna även utsätts för luft i verkligheten, har även

exponeringar i luft vid förhöjd temperatur utförts. De exponerade materialen har

utvärderats med avseende på volymsvällning, ändring i hårdhet och mekaniska

egenskaper samt sättning. Det sistnämnda är en mycket relevant egenskap för att

bedöma risken för läckage.

Resultaten visar att typ av gummi påverkar och att vissa gummityper lämpar sig bättre

än andra i olika bränslen. Fluorgummi visade sig till exempel fungera bra i både diesel

med 7 % biodiesel och etanolbränsle. Även luft hade smärre inverkan på dessa material.

Nitrilgummimaterialen uppvisade stora skillnader i diesel med 7 % biodiesel, beroende

på sammansättning. Alla sorters nitrilgummi klarade sig däremot bra i etanolbränsle,

men dåligt i luft. En specialvariant av nitrilgummi kan också komma att användas i

diesel med 7 % biodiesel. En typ av etenakrylgummi svällde mycket i etanolbränsle, men

klarar i övrigt av både varm luft och diesel med inblandning av 7 % biodiesel.

II

Acknowledgments I would like to thank all the people at Scania that have helped me during my diploma

work, especially my supervisor Maria Conde for great support during the whole process.

I would also like to thank Martin Bellander for good advice and Christian Sjöstedt for

help in the lab and for good music during lab sessions. Thank you Jenny Johansson and

Karin Agrenius, at SP Technical Research Institute of Sweden, for help during the project

and for letting me visit you in Borås. Thank you Erica Forslund at Trelleborg Ersmark AB

for providing the samples and for technical support.

Great thanks to the whole team at UTMC, Materials Technology at Scania, you have all

been very kind and helpful. Finally I would like to thank my friends and family for

supporting me.

Emmy Selldén

III

Contents Svensk sammanfattning ................................................................................................................................. I

Acknowledgments .......................................................................................................................................... II

Acronyms and glossary of rubbers ........................................................................................................... V

1 Introduction .............................................................................................................................................. 1

1.1 Background ...................................................................................................................................... 1

1.2 Aim and goals .................................................................................................................................. 2

2 Theory ......................................................................................................................................................... 3

2.1 Rubber materials ............................................................................................................................ 3

2.1.1 Description of some elastomers used in rubber ....................................................... 3

2.1.2 Additives ................................................................................................................................... 7

2.2 Fuels .................................................................................................................................................... 8

2.3 Degradation of rubber and interaction with fluids ........................................................ 10

2.4 Accelerated tests ......................................................................................................................... 12

2.4.1 Arrhenius equation ............................................................................................................ 12

2.4.2 Fluid resistance tests ........................................................................................................ 13

2.5 Previous research ....................................................................................................................... 14

3 Methods ................................................................................................................................................... 16

3.1 Rubber components analyzed ................................................................................................ 16

3.2 Fuels used ...................................................................................................................................... 18

3.3 Choice of time and temperature for exposures ............................................................... 18

3.4 Sample preparation .................................................................................................................... 19

3.5 Aging in air and exposure in fuels ........................................................................................ 19

3.6 Analysis of samples .................................................................................................................... 21

3.6.1 Volume change .................................................................................................................... 21

3.6.2 Change in hardness ............................................................................................................ 22

3.6.3 Tensile testing ..................................................................................................................... 23

3.6.4 Compression set ................................................................................................................. 24

3.6.5 FTIR ......................................................................................................................................... 25

4 Results and discussion ....................................................................................................................... 27

4.1 Visual observations .................................................................................................................... 28

4.2 FTIR analysis ................................................................................................................................. 30

4.3 NBR materials ............................................................................................................................... 34

IV

4.4 HNBR materials ........................................................................................................................... 38

4.5 AEM materials .............................................................................................................................. 41

4.6 FKM materials .............................................................................................................................. 44

4.7 Hoses ................................................................................................................................................ 48

4.8 Comparison between polymer types .................................................................................. 51

4.9 Testing in B100 ............................................................................................................................ 52

4.10 Reflections ..................................................................................................................................... 52

5 Conclusions ............................................................................................................................................ 53

6 Further work ......................................................................................................................................... 54

7 References .............................................................................................................................................. 55

Appendix A: FTIR spectra .......................................................................................................................... 58

Appendix B: Color graded tables for properties after fuel exposure and aging in air ....... 94

Appendix C: Bar charts for hoses ........................................................................................................... 98

V

Acronyms and glossary of rubbers Nomenclature of rubbers according to Swedish standard SS-ISO 1629

ACN Acrylonitrile AEM Copolymer of ethyl acrylate (or other acrylates) and ethylene. Ethylene-acrylic rubber AR Aramid Reinforcement ASTM American Society for Testing of Materials ATR Attenuated Total Reflectance B100 100% biodiesel B7 Diesel with 7% RME CO Polychloromethyloxirane. Epichlorohydrin rubber. CPE Chlorinated Polyethylene Rubber CR Chloroprene Rubber CS Compression set DLO Diffusion Limited Oxidation ECO Copolymer of ethylene oxide and chloromethyloxirane. Known as epichlorohydrin

copolymer or rubber ED95 Ethanol fuel of 95% ethanol and 5% additives FAME Fatty Acid Methyl Esters FKM Fluoro rubber having substituent fluoro, perfluoroalkyl or perfluoroalkoxy groups on

the polymer chain FPM Same as FKM FTIR Fourier Transform Infrared Spectroscopy GECO Terpolymer of epichlorohydrin-ethylene oxide-allyl glycidyl ether HNBR Hydrogenated acrylonitrile-butadiene rubber IRHD International Rubber Hardness Degree NBR Acrylonitrile-butadiene rubber, known as nitrile rubber PVC Poly Vinyl Chloride RME Rapeseed Methyl Ester SIS Swedish standards institute SS Swedish Standard

1

1 Introduction This diploma work has been performed at Scania CV AB, a manufacturer of heavy trucks,

buses and industrial and marine engines. Material selection is an important part when

developing new components. In this part, a background to the use of rubber components

in contact with fuel will be given, followed by aim and goals for the project.

1.1 Background

The main applications of rubber materials in heavy vehicles are in components for

sealing, vibration damping, fluid transportation and in interior details. In particular,

tightness of seals and hoses for fluid transport are of great importance for the

environmental performance, the driving safety, uptime and economy of the transport.

Fuel hoses are used in several parts of the fuel system in low and medium pressure

applications. They are used in the tank area in the fuel filler system and in the engine as

feed hoses to direct the fuel towards the fuel injector. Rubber hoses are also used to

connect the tank and engine compartment and consist of feed hoses that transport fuel

to the engine and as return hoses that transport unreacted fuel back to the tank. Fuel

hoses consist typically of several layers of materials. The inner rubber layer is in direct

contact with the fuel. Behind the inner layer, reinforcement is used. Depending on

temperature it can, for example, be polyester, cotton or aramid. Outermost is an external

rubber layer that faces the outer environment and it should be able to resist weather,

fuel, high external temperature, ozone, coolant, vibrations etc. Depending on the

materials used for the inner and outer layer, an intermediate layer might be used. The

intermediate layer gives less permeation and gives better adhesion between the layers

and the reinforcement [1].

Sealings are used to prevent leakage and exclude contaminants. Several materials can be

used like metal and rubber. Rubber has low hardness which allows for lower sealing

pressures and it has elasticity making it possible to maintain the pressure [2]. Rubber is

therefore common in sealings and gaskets. Many types of sealings and gaskets are

available on the market. Commonly used are radial, axial and O-ring sealings. Radial

sealings consist of several components, where one is a gasket cuff made of rubber. It is

used to prevent the transportation of fluid between two parts where, for example, one

part is stationary and the other is rotating. Axial sealings are commonly used to exclude

external contamination. O-rings are circular sealings used for both radial and axial

sealing. The O-ring is placed in a groove between two parts. When subjected to a load, it

deforms and seals [2]. One example of an important gasket is the cylinder head gasket

between the engine block and the cylinder heads in the engine. This gasket comes in

contact with oil, unreacted fuel and degraded fuel.

The temperature in the fuel system varies and there are areas that are colder and

warmer. For example, the fuel transport for injection in the engine transports cold fuel

2

and the temperature is rarely over 60⁰C. For transportation of unreacted fuel, the

temperature is higher.

To reduce repair cost and to ensure safety it is wished that rubber articles have a life-

time close to the truck life.

To estimate how good rubber components will perform in fuel, accelerated tests are

commonly performed according to Swedish standard SS-ISO 1817 or American standard

ASTM D471, these tests are normally short, for example 70h [3]. There is a need to

perform these tests at longer times, about 1000h, in real fuels to better estimate how

good different rubber components will perform during long time in service. In this

diploma work, three fuel hoses and thirteen rubbers will be examined in air and some in

commercial fuels. The rubber components are three types of nitrile rubber (NBR), two

types of hydrogenated nitrile rubber (HNBR), four types of ethylene-acrylic rubber

(AEM) and four types of fluorocarbon rubber (FKM). NBR and HNBR are used in lower

temperature applications while AEM and FKM are used at higher temperatures.

1.2 Aim and goals

This study aims to obtain relevant data to predict the long-term properties of rubber

components used in applications in commercial fuels such as diesel with 7% RME

(rapeseed methyl ester), biodiesel and ethanol fuel. This information will help to give

safer recommendations on the life assessment of different rubber materials in fuels.

The questions to be answered are:

Which of the chosen rubber materials have the potential to be used in fuel

applications, for long-term use, in commercial fuels like diesel with 7% RME,

biodiesel and ethanol fuel?

How does polymer type and differences in composition of the different rubber

components impact on aging and fuel resistance?

3

2 Theory In this section, information from literature relevant for the understanding of the project

is presented. It begins with a description of typical rubbers used in fuel and is followed

by information on different fuels. A brief overview of the interaction of rubber and fluids

is given and accelerated tests are discussed. Finally, results from previous research are

presented.

2.1 Rubber materials

Rubber materials consist of special polymers showing high elastic properties. The main

part of rubber consists of elastomers which are long, chainlike molecules that can be

stretched at a great extent and then has the ability to recover to its original shape [4].

The elasticity originates from the movable and sparsely cross-linked molecules of these

materials [5]. In order to improve the physical properties, rubbers are vulcanized, which

is a chemical process where cross-links are formed between the polymeric chains [6].

Rubber materials consist of several components in addition to elastomers like cure

system, fillers, softeners, aging protective agents and other additives. A brief description

of some elastomer types are given below, followed by an overview on different

additives.

2.1.1 Description of some elastomers used in rubber

Nitrile rubber

Nitrile rubber (NBR) is a copolymer of butadiene and acrylonitrile (ACN), see Figure 1.

The amount of ACN affects several properties like petroleum oil and fuel resistance,

tensile strength, hardness and low temperature properties. A higher amount of ACN

gives better petroleum oil and fuel resistance, improved tensile strength and increased

hardness, but at the cost of low temperature properties [7]. In general NBR has good

resistance to oil, aliphatic and aromatic hydrocarbons and vegetable oils, but poor

resistance to polar solvents like esters and ketones, where it swells, because NBR is a

polar rubber [8] [7]. Because of the double bond present in the backbone, NBR is

vulnerable to oxygen, ozone and UV light.

Figure 1. Repeating units of NBR. To left: butadiene unit, to right: acrylonitrile unit.

4

Hydrogenated nitrile rubber

In hydrogenated nitrile rubber (HNBR), some or all double bonds in NBR has been

removed by hydrogenation, see Figure 2. This makes HNBR more resistant to oxidation

than NBR and gives it improved temperature and chemical resistance [9].

Figure 2. Repeating units of HNBR. To left: fully hydrogenated butadiene unit, to right: acrylonitrile unit. Ethylene-acrylic rubber

Ethylene-acrylic rubber (AEM) is a copolymer of methyl acrylate (or other acrylates)

and ethylene, see Figure 3 . Its trade name is DuPont™ Vamac® and is available in

several grades, some used in this diploma work. Vamac® G is the base grade, Vamac®

GLS has greater swelling resistance in oil and diesel fuel compared to Vamac® G and has

a higher amount of methyl acrylate. Vamac® HVG is similar to Vamac® G but has higher

viscosity [10]. Generally, AEM shows poor chemical resistance towards aliphatic,

aromatic and chlorinated hydrocarbons. Better resistance is shown towards mineral

oils, natural fats and some salts [7].

Figure 3. Repeating units of AEM. To left: ethylene unit, to right: methyl acrylate unit.

Fluoro rubber

Fluoro rubber, (FKM, sometimes abbreviated FPM in some standards), has a fluorinated

carbon-carbon backbone. There are many types of monomers available and ASTM

D1418 has divided FKM into five types:

Type 1: Dipolymer of hexafluoropropylene and vinyldiene fluoride, see Figure 4.

The fluorine content is usually ~66% and it is used for general purposes [11].

Type 2: Terpolymer of tetrafluorethylene, vinylidene fluoride and

hexafluoropropylene, see Figure 5. The fluorine content is 66-70% which gives it

improved resistance towards oil, solvents and fuels [11].

Type 3: Terpolymer of tetrafluoroethylene, a fluorinated vinyl ether and

vinylidene fluoride, see Figure 6. The fluorine content is usually 64-67%. It has

improved low temperature properties but worse chemical resistance [11].

5

Type 4: Terpolymer of tetrafluoroethylene, propylene and vinylidene fluoride.

Type 5: Pentapolymer of tetrafluoroethylene, hexafluoropropylene, vinylidene

fluoride, ethylene and fluorinated vinyl ether.

Figure 4. Repeating units of FKM type 1. To left: hexafluoropropylene, to right: vinylidene fluoride.

Figure 5. Repeating units of FKM type 2. To left: hexafluoropropylene, middle: vinylidene fluoride, to right: tetrafluorethylene.

Figure 6. Repeating units of FKM type 3. To left: vinylidene fluoride, middle: tetrafluoroethylene, to right: perfluormethylvinylether (example of a fluorinated vinyl ether). Due to the high bonding energy of C-F bonds and shielding of polymer backbone by

fluorine, FKM has good high temperature resistance and resistance to oxidation, ozone,

fuel and petroleum oils [12]. FKM swells in polar solvents such as low molecular esters

and ketones [8]. Higher fluorine content increases the temperature and chemical

resistance [7], but the low temperature performance and compression set is worse [13].

6

FKM is commonly cured with peroxide or bisphenol. Peroxide cured FKM generally give

weaker cross-links and results in worse aging resistance compared to bisphenol cured

FKM [12]. The resistance to acids, steam and hot water is better compared with

bisphenol [14].

One of the trade names of FKM is DuPont™ Viton®. Two types that are studied in this

diploma work are Viton® GBL-S and Viton® GFLT. GBL-S is of type 2 and GFLT of type 3

where the fluorinated vinyl ether is perfluormethylvinylether, both has an additional

cure site monomer [15].

Epichlorohydrin rubber

Epichlorohydrin rubber is a group of three types of rubbers of halogenated polyethers,

all with the epichlorohydrin monomer. An elastomer of epichlorohydrin homopolymer

is designated CO. If epichlorohydrin is copolymerized with ethylene oxide one obtains an

elastomer designated ECO, see Figure 7 [12]. GECO is a terpolymer of epichlorohydrin,

ethylene oxide and allylglycidylether [16]. Epichlorohydrin rubber is polar, where CO is

most polar. It has good resistance to petroleum fuels, alcohols, oxygen, ozone and light

[7].

Figure 7. Repeating units of CO and ECO. To left: epichlorohydrin unit, to right: ethylene oxide unit.

Chloroprene rubber

Chloroprene rubber (CR) consists of chloroprene units, see Figure 8. Due to the chlorine

atoms present, CR is a polar rubber. The chlorine atoms give the rubber better

resistance to weather and ozone. The swelling resistance in vegetable oils and animal

fat is better compared to non-polar diene rubbers, but less compared to NBR [12].

Figure 8. Repeating unit of CR. Chloroprene unit.

7

Chlorinated polyethylene rubber

Chlorinated polyethylene (CPE) is produced by chlorinating polyethylene, see Figure 9.

Polyethylene is a crystalline polymer and not a rubber. By introducing chlorine,

crystallization is prevented and an elastomer is obtained. How rubbery the polymer will

be depends on the degree of chlorination. Chlorinated polyethylene rubber is polar and

hence oil resistant and due to the saturation it is less sensitive towards oxygen, ozone

and light [7].

Figure 9. Repeating units of CPE. Chlorinated polyethylene.

2.1.2 Additives

Cure system

Sulfur is the most used cross-linking agent and is used when the elastomers are

unsaturated. Sulfur reacts chemically with double bonds to form cross links between the

chains. To speed up the vulcanization, zinc oxide, stearic acid and accelerators are

added. Zinc oxide reacts with stearic acid [8] to work as an activator [17]. Accelerators

are usually organic chemicals. Some accelerators give a slow cross linking, some gives

fast cross-linking and some are used to delay the cross-linking [8].

When no double bonds are available, peroxide can be used. Peroxide does not need zinc

oxide, stearic acid and accelerators. Sometimes so called co-agents are used to improve

the vulcanization. The peroxide acts by removing a hydrogen atom from the polymer

chain and creating a radical. A radical on one site can react with a radical on another site

and hence create a cross-link. Peroxide cured systems gives a better compression set

than sulfur but has reduced tensile strength. Other cross-linking agents than sulfur and

peroxide are metal oxides, which are used on halogen containing elastomers, and some

amines alternatively bisphenols which can be used on fluoroelastomers and polyacrylate

[8].

Fillers

Fillers give reinforcement to the rubber, thereby increasing the mechanical strength and

stiffness. The size, shape and surface chemistry of the filler determine whether the

reinforcement will be high or low. Carbon black is commonly used as filler and is the

reason why rubbers often are black. Due to its surface activity the mobility of the rubber

is reduced as it adsorbs at the surface of the carbon black [7]. Other fillers used are

silica, clays and chalk [8].

8

Softeners

Softeners, also known as plasticizers, are used to increase the deformability (elongation)

of a polymeric material as described in ASTM D 1566. Softeners can be used, for

example, to reduce hardness, reduce viscosity of uncured material and improve low

temperature properties. One of the major sources of softeners is petroleum oils. In order

to use oil, the elastomer has to have low or no oil resistance. If the elastomer is oil

resistant, polar liquids, like ester, can be used [8].

Aging protective agents

Antioxidants, also called stabilizers, are added to neutralize free radicals to protect the

rubber from aging, which is caused by oxygen and accelerated at elevated temperatures.

To protect the material from ozone, antiozonants are added [8].

2.2 Fuels

To reduce CO2 emissions and decrease the dependence of oil, the use of other fuels

alternative to diesel has increased in recent years, in particular biodiesel (consisting of

fatty acid methyl esters, FAME) and bioethanol [18]. Ethanol fuel is used in buses and

trucks, biodiesel is used in several types of vehicles. Biodiesel can be used in its pure

form (designated B100, meaning 100% biodiesel) or in blends with diesel.

There are European emission standards, designated Euro I, II, III and so on, that

regulates how much emissions heavy vehicles may emit. To be certified according to a

Euro standard, reference fuels are used to assure that the standard is fulfilled. Euro VI is

the latest standard and comes into force during 2013. Earlier (Euro V), diesel with 5%

FAME was approved as reference fuel. With Euro VI a reference fuel of diesel with 7%

FAME is introduced [19]. In this section a description of diesel, biodiesel and ethanol

fuel will be given.

Diesel

Diesel is produced by distillation of petroleum crude oil. Petroleum crude oil consists of

hydrocarbons like paraffins, naphtenes and aromatics. Paraffins1 has the general

formula CnH2n+2 and is divided in to normal paraffins, which are long, straight chains of

hydrocarbons, and isoparaffins, which are long chains with branches, see Figure 10 [20].

Naphtenes2 are saturated hydrocarbons with some carbons in a ring. In diesel, the rings

in naphtene, have five or six carbon atoms [20]. Aromatics are unsaturated

hydrocarbons arranged in rings of six carbons. The carbons in the ring are joined by

aromatic bonds [20]. After some refinery processes a group of hydrocarbons called

olefins might be present. Olefins are hydrocarbons having one or more double bonds

[20]. Other compounds than hydrocarbons, containing sulfur, nitrogen and oxygen, are

also present in petroleum crude oil [20].

1 In petrochemical chemistry the term paraffins is used for acyclic alkenes (saturated carbons) [58]. 2 Other names are cycloalkanes and cycloparaffins. [20]

9

Diesel, with a boiling point of 150-380°C [21], is a mixture of hydrocarbons of 10 to 22

carbon atoms [21] and consists of 50-70% paraffins, 30-45% naphtenes and 3-5%

aromatics [22]. The ratio and length of the different hydrocarbons gives the diesel

different properties like boiling point, freezing point, density, heating value3, viscosity

and cetane number. The cetane number is a measure of the ignition quality, i.e. how

readily a fuel starts to burn once it has been injected into the cylinder. Aromatics tend to

swell elastomers so the amount of aromatics present in the diesel is of importance for

elastomeric behavior [21]. Additives are added to diesel to improve fuel handling,

system performance, thermal stability and to control contamination [20].

Figure 10. Different hydrocarbons present in petroleum crude oil. Biodiesel

Biodiesel consists of mono alkyl esters produced from feedstock of vegetables and

animals. Common vegetable plants used as feedstock are soybean (most common in

USA), rapeseed (most common in Europe) and palm oil [23]. Vegetable oils and animal

fats consist of triglycerides which are hydrocarbons bonded to a glycerol molecule [20].

The triglycerides can be converted to FAME through a process called transesterification.

The transesterification is carried out by reacting the triglycerides with an alcohol,

commonly methanol, under the presence of a base [20] [23], see Figure 11. The resulting

product, FAME, has alkyl chain lengths of 12 to 22 carbons depending on feedstock and

is used as biodiesel [20].

Different feedstock gives different types and amounts of fatty acids, which influences the

oxidation resistance of fuel [24]. Biodiesel does have some residual byproducts from the

transesterification like glycerol, acylglycerols and methanol [25]. The amount of these

byproducts and free fatty acids are regulated by different standards like ASTM D6751

and European standard EN 14214.

3 The heating value is the amount of heat released for a certain amount during combustion.

10

Because of the structure of unsaturated fatty esters in the biodiesel, there are some

oxidative stability problems [25]. Oxidation of biodiesel can convert esters into

carboxylic acids which gives enhanced corrosion and degradation of fuel properties,

peroxides are also formed [26]. Compared to diesel, biodiesel takes up more water,

which might promote microbial growth. It has increased polarity and solvency, which

can cause the degradation of some elastomers [26].

Figure 11. Reaction scheme for the transesterification of vegetable oils. Ethanol fuel

Ethanol is produced from sugar, starch or cellulosic biomass. Depending on plant it is

produced in different ways. If sugar canes are used the sugar can be fermented directly.

If the source is starch, which is the case when using e.g. maize, it has to be converted into

glucose before fermentation [27].

A commercial ethanol fuel is ED95, consisting of 95% ethanol and the remaining 5% are

ignition improver, lubricants and other additives [28], see Table 1.

Table 1. Example of content of ED95. Information given from safety sheet by SEKAB.

Substance Weight%

Ethanol 90-92

Glycerol etohxylate 4-7 Methyl-t-butyl ether < 3

Isobutanol < 1

Lubricant < 2

2.3 Degradation of rubber and interaction with fluids

Degradation of rubber and other polymeric materials means irreversible deterioration

of the physical and chemical properties [29]. There are many types of factors that can

cause the degradation. These are temperature, light, ionizing radiation, humidity, fluids,

bio-organisms, mechanical stress and electrical stress [30]. The degradation can be due

to bond scissions in the polymer chain, breaking of cross-links and formation of new

cross-links. It can also be due to extraction of and chemical attack on additives in the

rubber [29]. Chain scission is seen as a deterioration of mechanical properties while the

formation of additional cross-links is seen as an increase in hardness and modulus [31].

11

Thermo-oxidative degradation is a common reaction mechanism. High temperatures

give rise to the formation of radicals by cleavage of carbon-carbon and carbon-hydrogen

bonds. The radicals react with oxygen, forming peroxide radicals which can continue to

react with the rubber [32]. A commonly used reaction scheme can be seen in Figure 12.

Figure 12. Common reaction scheme for oxidation of rubber. RH is the rubber polymer. Reaction scheme as suggested in [32]. Fluids can cause chemical degradation, swelling, cracking and extraction of additives of

rubber. Swelling is caused by absorption of fluid in to the polymer network. A general

rule is that polar substances dissolves better in polar liquids and non-polar substances

dissolves better in non-polar liquids [33]. Biodiesel is chemically different than diesel

and contains more polar esters. Therefore swelling of polar elastomers is greater in

biodiesel than in diesel. Swelling is observed when more liquid is absorbed than soluble

components are being extracted from the rubber. If, in contrary, the volume decreases it

might be due to soluble components being replaced by less dense solvent molecules or

that the extraction of additives is greater than the absorption of solvent [33]. Volume

change is increased at higher temperatures [31].

The volume increase is often accompanied with a decrease in hardness due to

plasticization when fuel is absorbed. If larger changes in hardness are seen, it might

indicate chain scission or formation of additional cross-links [34]. Additional cross-links

might give an increase in hardness. This can also be observed if there has been loss of

softeners. Chain scission can result in a decreased hardness.

If the volume change is purely physical, change in tensile strength and elongation at

break are slightly reduced. If a large deterioration is observed, it is probable that

chemical reactions has occurred (this applies for aged samples too). Tensile strength is

usually decreased if cross-links have been attacked, while chain scission might be

observed as a reduction in both tensile strength and elongation at break [34]. Additional

cross-links can result in an increased tensile strength.

12

2.4 Accelerated tests

Since the life time of rubber components is typically some years, it is not practical to

perform tests for such a long time. To estimate how well a material will perform during

its life time, accelerated tests are used, commonly by increasing the temperature. There

are standards used in the industry on how to perform these tests. SS-ISO 188 is used for

accelerated aging4 and SS-ISO 1817 is used to determine the effect of fluids by so called

fluid resistance tests. In this section the Arrhenius equation will be introduced followed

by a short description of fluid resistance tests.

2.4.1 Arrhenius equation

The Arrhenius equation gives the relation between the reaction rate and the

temperature for a chemical reaction:

(1)

The equation can also be expressed as:

(2)

Where

k = the rate constant for the reaction [time unit-1]

A= a pre-exponential factor

R = the gas constant (8.314472 JK-1mol-1)

T = the temperature [K]

Ea = the activation energy [Jmol-1]

With the Arrhenius equation, tests performed at higher temperatures can be used to

predict the performance of a material at longer times at lower temperatures and can

therefore be used for life time predictions [8]. If the activation energy is known for the

reaction that dominates, or if the average activation energy for several reactions is

known, the time needed for accelerated testing, t1, at a certain temperature, T1, may be

calculated. The exposure time for the accelerated aging test would correspond roughly

to the wished lifetime, t2, and operation temperature, T2. Using the Arrhenius equation:

(3)

4 Aging refers to degradation caused by oxygen.

13

If the activation energy is unknown, one way to decide the time for accelerated tests, is

to assume an Ea. Typically, Ea in the order of 80-150 kJmol-1, is found [35] [36] [37].

Assuming an Ea is of course a rough estimation, but to obtain data for Arrhenius

extrapolations in order to determine Ea is very time consuming.

Drawbacks of using the Arrhenius equation

Several assumptions are made when using the Arrhenius equation. It is assumed that the

same reactions occur under service conditions as under testing conditions. The

Arrhenius equation describes the temperature dependence for one chemical reaction, in

reality there can be several reactions occurring and the reactions can be complex and

not as easy as the equation suggests. It is also assumed that the activation energy is

independent of temperature [29].

There are several studies proving non-Arrhenius behavior, which is seen as a non-linear

behavior when plotting data. Some studies are reviewed by M. Celina et al [38]. Kenneth

T. Gillen et al [39] has reviewed the limitations of using the Arrhenius equation. It is

described that oxidation, which is often given by a simple equation described by the

Arrhenius equation, in fact is a set of chemical reactions. By steady state analysis it is

predicted that the Ea can be non-constant.

It is also discussed that diffusion-limited oxidation (DLO) can give non-Arrhenius

behavior. DLO means that oxygen is consumed within the material faster than oxygen

can be resupplied from the surroundings. The surface is not affected by this, but DLO can

be seen deeper within the material where less oxidation occurs [39]. Another

mechanism that can give non-Arrhenius behavior is when two pathways give rise to

degradation in a material. If one reaction has a lower Ea compared to the other, this

reaction will not be evident until lower temperatures.

2.4.2 Fluid resistance tests

Normally, fluid resistance tests are done by immersing test pieces in liquids, such as fuel.

The effect of liquid on the rubber is evaluated by measuring certain properties like mass

change, volume change, hardness and tensile-stress properties [40] [41] [42] [43].

Drawbacks of immersion tests

The disadvantage of immersion tests and other standard laboratory tests is that the

experimental conditions differ from real service conditions and hence material selection

can be incorrect [44]. Gordon Micallef et al [44] have compared standard laboratory

testing (according to standard ASTM D2240 hardness, ASTM D412 stress-strain and

ASTM D471 fluid immersion) with testing under service conditions for different fluoro

rubbers in different fuels. Under service conditions, water contamination is common

and, especially in biodiesel since water is more soluble in biodiesel than in diesel [44].

The water contaminated fuel gave a large deterioration of some of the elastomers

compared to standard laboratory tests and it is suggested that the water causes

hydrolysis of esters in biodiesel which open up for other chemical reactions than in fuel

14

without water. This is just one example of how real service conditions can give

differences in properties of great importance and this is important to bear in mind.

2.5 Previous research

There are general recommendations on what type of rubbers that has good or poor

resistance to certain fluids. “The Los Angeles Rubber Group” has put together a chemical

resistance guide, which can be found in DuPonts Chemical resistance guide [45]. Some of

the results are summarized in Table 2. Available are also ratings for the suitability of use

for some elastomers in different chemicals at room temperature, the result for ethanol

and diesel oil is presented in Table 3. Ratings are based on data from several suppliers

and manufactures and the criteria used for rating was volume swell resistance,

compression set resistance and aging resistance when applicable. How the data was

obtained is not stated.

Table 2. General chemical resistance for some elastomers, information taken from [45].

Elastomer Generally resistant to Generally attacked by

NBR Many hydrocarbons, fats, oils, greases, hydraulic fluids, chemicals

Ozone, ketones, esters, aldehydes, chlorinated and nitro hydrocarbons

HNBR Similar to NBR but with improved chemical resistance and higher service temperatures

Ozone, ketones, esters, aldehydes, chlorinated and nitro hydrocarbons

ECO Similar to NBR with ozone resistance

Ketones, esters, aldehydes, chlorinated and nitro hydrocarbons

AEM Weather, ozone, hydrocarbon lubricants/greases, hydraulic fluids

Aromatic hydrocarbons, esters, gasoline, ketones

FKM Dipolymer, 66% fluorine

All aliphatic, aromatic and halogenated hydrocarbons, acids, animal and vegetable oils

Ketones, low molecular weight esters and alcohols and nitro containing compounds

Table 3. Ratings for the suitability of some elastomers in ethanol and diesel oil at room temperature, ratings taken from [45]. 1 = little to minor effect, 0-5% volume swell, 2 = minor to moderate effect, 5-10% volume swell, 3=moderate to severe effect, 10-20% volume swell, 4=not recommended. Time and way of testing is not stated.

Elastomer Rating in ethanol Rating in diesel oil

NBR 1 1

HNBR 1 1 ECO 2 1

CR 1 3

AEM 4 1

FKM, dipolymer 2 1

FKM, terpolymer 1 1

15

A.S.M.A Haseeb et al [41] have performed immersion tests in different concentrations of

palm biodiesel in diesel at 25°C and 50°C for 500h. Tests were performed on NBR, CR

and FKM (Viton A), the contents of these rubbers are not specified which is unfortunate

since the amount of ACN in NBR is of great importance [7]. NBR and CR showed

deterioration in properties while negligible changes were shown for FKM.

F.N. Linhares et al [43] conducted immersion tests at 70°C for 70h in Brazilian biodiesel

(ethylic biodiesel from coconut oil and castor bean oil). Three different samples of NBR

with different ACN content were tested (28, 33 and 45% ACN). It was concluded that

Brazilian biodiesel can degrade NBR but that increasing ACN content can prevent the

degradation. NBR with 45% ACN appeared to be resistant to the biodiesel used in this

study.

Gordon Micallef and Axel Weimann [44] performed immersion tests in diesel and in

diesel blended with 30% RME of several types of FKM of varying type and fluorine

content. After immersion at 150°C for 336h the volume change was under 10% for all

types and the changes in mechanical properties was not of the degree that it would

affect the actual performance of the rubbers.

E. Frame and R.L McComeric [46] have published a technical report of the compatibility

of some elastomers in diesel blended with 20% biodiesel (from soybean) and diesel

blended with 15% ethanol. The rubbers tested were NBR, NBR with high ACN content,

peroxide-cured NBR, FKM filled with carbon black and FKM without carbon black.

Immersion was performed at 40°C for 500h. All samples, except from NBR with high

ACN content, showed decreased break load after immersion in ethanol blended diesel as

compared to diesel. This was not seen in the biodiesel blend. Volume swell was larger in

ethanol blended diesel compared to biodiesel blend and diesel. The overall conclusion is

that all the tested rubbers seem to be compatible in diesel blended with 20% biodiesel

but less compatible in diesel with 15% ethanol.

Wimonrat Trakarnpruk et al [42] studied the impact of 10% biodiesel (from palm oil) in

diesel on six types of rubbers in 100°C for 23, 670 and 1008h. The rubbers were NBR,

HNBR, NBR/poly vinyl chloride (PVC), acrylic rubber, FKM – dipolymer and FKM-

terpolymer. Mass change, volume change, hardness change, tensile strength and

elongation were measured. None of the materials showed a significant change in

properties.

Concluding remarks on previous research

No research has been found on the effect of ethanol fuel on rubber components. There

are recommendations for pure ethanol, as seen in Table 3, but since there are additives

in ethanol fuel that can affect the properties, further studies would give valuable

information.

Studies on RME are sparse and even though there are studies of biodiesel derived from

other feedstock, a study on testing in RME would be interesting since different feedstock

16

gives different types and amounts of fatty acids [24] and thereby also might affect the

impact on rubbers.

In many studies the acceleration factor is too high, i.e. materials are tested at too high

temperatures for too short time. There is a risk of accelerating tests too fast. At

temperatures higher than the rubber component is usually subjected to, new chemical

reactions can occur. It can for example be melting of material and migration of additives.

Short term tests, like one week, is therefore not good for predicting long-term properties

since the temperature has to be raised significantly to correspond to the operation time.

In this case, extrapolation to lower temperatures may result in wrong assessment of the

expected life time. Slower accelerations for longer times at lower temperatures,

decreases the risk of unwanted chemical reactions, hence better for predicting the long-

term performance. Since studies on rubber components for several weeks are rare, tests

at 1000 hours or longer would give the data needed to better predict the life time.

3 Methods Fluid resistance tests by immersion in the different fuels are chosen to achieve the aim

and goals of this diploma work. This is because they are used frequently in other

investigations, as previously described, and they are relatively easy to perform. Aging in

air is carried out in addition to fluid resistance tests since warm air will be available in

real service conditions. This will indicate if there is a risk of embrittlement of the

materials during service.

SS-ISO 1817 forms the basis of the experimental set up for fuel exposures and involves

immersion in fuels and evaluation of change in properties before and after exposure.

Some of the methods described in SS-ISO 1817 are selected. These are: change in

hardness, volume and tensile stress-strain properties. The performance of rubber

materials in sealings is evaluated by so called compression set according to SS-ISO 815-1.

Material characterization, to provide information on molecular changes in rubber before

and after immersion, is provided by Fourier Transformed Infrared Spectroscopy (FTIR).

This chapter gives a description of the rubber components analyzed, fuels used and the

analyses performed.

3.1 Rubber components analyzed

Thirteen rubber materials were obtained from Trelleborg Ersmark AB in form of

compression molded sheets. Three fuel hoses were obtained from external companies.

The materials in the rubber sheets were: three types of NBR, two types of HNBR, four

types of AEM and four types of FKM. These materials are the same used in a diploma

work by Sara Wengström, Scania CV AB, 2012 [47], that aimed to study their low

temperature properties. The fuel hoses consisted of several layers and were: one hose of

FKM/ECO/AR/ECO where AR is aramid reinforcement, one hose of HNBR/CPE with

reinforcement and finally a hose of NBR/CR with reinforcement. Information on the

different rubber sheets and hoses is given in Table 4.

17

Table 4. Information on the rubber components analyzed.

5 TR10 is the temperature where the rubber retracts 10% from an original stretch in frozen condition [56]. 6 The type of phosphate is unknown. Common types are tributhoxyethyl phosphate and tricresyl phosphate [65].

Assigned name

Type Rubber Trade name Color TR105

(⁰C) Cross linking agent Filler Softeners Other information

NBR_1 sheet NBR Black -32 Sulfur Carbon black Ether, 5% ACN 30.5%. Standard blend.

NBR_2 sheet NBR Black -50 Sulfur Carbon black Ether, 10% ACN 19%. Low ACN blend.

NBR_3 sheet NBR Black -40 Sulfur Carbon black Phosphate,6 10%

ACN 29.5%. Low temperature blend.

HNBR_4 sheet HNBR Black -15 Peroxide Carbon black None ACN 34%, fully saturated.

HNBR_5 sheet HNBR Black -32 Peroxide Carbon black Dioctyl sebacate, 7-9%

ACN 21%, partly saturated.

AEM_6 sheet AEM Vamac HVG Black -32 Diamine Carbon black Adipate, 12 parts

Standard composition.

AEM_7 sheet AEM Vamac GLS Black -31 Diamine Carbon black Adipate, 18 parts

Low swell.

AEM_8 sheet AEM Vamac HVG Black -39 Diamine Carbon black Adipate, 22 parts

Different fillers than AEM_6.

AEM_9 sheet AEM Vamac HVG/G

Black -34 Diamine Carbon black Adipate, 14 parts

FKM_10 sheet FKM Green -15 Bisphenol Barium sulphate None F 66%, type 1. Standard copolymer.

FKM_11 sheet FKM Viton GFLT Black -25 Peroxide Carbon black None F 67%, type 3. Low temperature

FKM_12 sheet FKM Black -13 Bisphenol Carbon black None F 68%, type 2. Standard terpolymer.

FKM_13 sheet FKM Viton GBL-S Black -17 Peroxide Carbon black None F 67.5%, type 2. Increased fluid resistance

hose_14 hose FKM/ECO/AR/ECO Black

hose_15 hose HNBR/CPE Black

hose_16 hose NBR/CR Black

18

3.2 Fuels used

Three fuels were used for exposure of samples: diesel with 7% RME (will be given the

abbreviation B7), biodiesel (B100) and ethanol fuel. B7 is a reference fuel used for

certification of Euro VI engines, it was provided from Preem. The biodiesel consists of

100% RME and was provided from Preem. The ethanol fuel was ED95 provided from

SEKAB.

3.3 Choice of time and temperature for exposures

The time of exposure was roughly estimated by using equation 3. The wished life time

for the rubber articles was set to 40000h. The continuous temperature in colder parts of

the fuel system was set to ~65⁰C and warmer parts to ~85⁰C. For about a total of 10% of

the wished rubber article life time, corresponding to 4000h, the temperature was

assumed to be elevated, with a temperature of ~80⁰C in the colder areas and ~120⁰C in

the warmer areas.

Activation energy of 96.5 kJ mol-1 (1eV) was assumed and the temperature of exposure

was chosen so that the acceleration factor would not be too high. The calculated time for

exposure, using equation 3, was rounded off to correspond to whole weeks. The result of

the Arrhenius calculation is presented in Table 5. The short term exposures (168h) at

higher temperatures were performed to see how the materials are affected at elevated

temperatures. To see the change in properties with time, an additional time was added

at about 500h for exposures at the lower temperature.

The exposure times and temperatures shown in Table 5 was used for aging in air.

Table 5. Assumed time and temperature in service with corresponding time and temperature for exposure.

Time in service, t2 (h)

Temperature in service, T2 (⁰C)

Time of exposure, t1 (h)

Exposure temperature, T1 (⁰C)

Used for rubber and hoses with:

40 000 ~65 1008 105 NBR, HNBR

40 000 ~85 1008 135 AEM, FKM, HNBR

4000 ~80 168 115 NBR, HNBR

4000 ~120 168 165 AEM, FKM

For exposures in B7and B100, the temperature for 168h and 165⁰C was lowered to

150⁰C, due to experimental set up limitations related to safety during testing in highly

flammable fuels.

For ED95, exposures were conducted for 504h and 1008h at 70⁰C, close to the boiling

point of ED95 (boiling point is ca 78⁰C), with exception for compression set that was

conducted at 115 and 150⁰C for 168h.

NBR and HNBR are usually used in colder areas while AEM and FKM are used in warmer

areas. HNBR can however withstand higher temperatures for shorter times and was

19

therefore tested at some of the higher temperatures. An overview of the time and

temperatures for exposures in fuel and air is presented in Table 6.

Table 6. Time and temperatures used for exposure in different fuels and in air of the rubber materials and hoses.

504h 1008h 70⁰C

504h 1008h 105⁰C

168h 115⁰C

504h 1008h 135⁰C

168h 150⁰C

168h 165⁰C

B7 NBR, HNBR NBR, HNBR AEM, FKM AEM, FKM, HNBR

B100 NBR, HNBR NBR, HNBR AEM, FKM AEM, FKM, HNBR

ED 95 NBR, HNBR, AEM, FKM

Compression set NBR, HNBR

Compression set AEM, FKM, HNBR

Aging in air

NBR, HNBR NBR, HNBR AEM, FKM, HNBR

AEM, FKM

3.4 Sample preparation

For all tests, with exception for compression set, dumbbells were used. Dumbbells from

rubber sheets and hoses were punched out, with size according to SS-ISO 37 type 2. The

parallel length and width of the narrow portion was 25mm and 4mm respectively. For

measurements of volume change, dumbbells cut in half were used.

Test pieces for compression set were punched out using a circular die, of size according

to SS-ISO 815-1. The diameter was 13 mm.

3.5 Aging in air and exposure in fuels

ED95 and B7

Due to the low flash point of B7 (ca 68⁰C) and ED95 (ca 10⁰C), exposures were

performed by SP Technical Research Institute of Sweden in Borås, in autoclaves. Not all

of the rubber components could be tested at SP so ten materials was selected: NBR_1,

NBR_2, NBR_3, HNBR_5, AEM_7, FKM_10, FKM_11, FKM_13 and hose_14 and hose_16. SP

performed the compression set for these samples and measured the volume change for

ED95 exposed samples. The rest of the samples were sent back so the other tests could

be performed.

B100

Only the exposure for 168h at 115⁰C in B100 could be conducted. When starting

exposure at 150⁰C, severe smoke generation was observed. It was concluded that the

flash point of B100 was significantly lower than measured by the supplier. Therefore the

other exposures in B100 could not be carried out. Exposures in B100 were performed by

hanging the samples on steel wire in flasks of 250 ml and fill the flasks with B100, see

Figure 13a).

20

Aging in air

Aging in air was performed in cell type ovens where only rubbers of same polymer type

were aged in the same cell. Samples were hung by hooks lined with

polytetrafluoroethylene on a stand and then placed in the cell, see Figure 13 b) and c).

a) b) c) Figure 13. Exposure in B100 and air. a) exposure in biodiesel, b) samples for aging hanging on stand, c) cell type oven used for aging.

21

3.6 Analysis of samples

Following is a description of the theory and execution of analysis.

3.6.1 Volume change

The volume of a test piece can be determined by fluid displacement methods.

Archimedes principle states that when a test piece is immersed in a fluid, an upward

force will act on the sample. The magnitude of the force equals the weight of fluid being

supplanted and the volume of supplanted fluid equals the volume of the test piece [48].

By weighing the sample in air and liquid before and after exposure in fuel, the

percentage change in volume, ΔV100, can be calculated by

(5) [49]

Where

ρ = the density of the liquid used for displacement

mi = the mass after exposure in fuel

mi,liq = the mass in liquid after exposure in fuel (including the mass of a sinker if it is

used)

ms, liq = the mass an eventual sinker

m0 = the initial mass

m0,w = the initial mass of the sample when weighed in water (including the mass of a

sinker if used)

ms,w = the mass of the eventual sinker

Water can be used as the liquid for displacement if the fuel is immiscible with water.

Equation 5 can then be expressed as

(6)

Where

mi,w = the mass in water after exposure in fuel (including the mass of a sinker if it is

used).

Measurements of volume change after exposures in B7, B100 and ED95 were carried out

by fluid displacement in water and equation 6 was used for calculating the volume

change, see Figure 14. For test pieces exposed to B7, weighing was performed after

about 24h, for test pieces exposed to B100 and ED95, weighing was performed 30min

after terminating the exposure. Three test pieces were used for each exposure.

It was discussed whether it is correct to weigh test pieces exposed in ED95 in water or

not. Ethanol is soluble in water and another fluid for displacement might have been

more appropriate. However, SP informed that the balance was stable during the

weighing and that no visible volume change could be seen when immersing in water. It

22

was concluded that weighing in water instead of other media should be of minor

importance.

Figure 14. Measurement for volume change. To left: weighing in air, to right: weighing in water.

3.6.2 Change in hardness

Hardness is the resistance to indentation. For hardness measurements of rubber, the

international rubber hardness degree (IRHD) scale can be used. It ranges from 0 to 100

where 0 is the hardness of a material having an elastic modulus of zero and 100 is the

hardness of a material having infinite elastic modulus [50]. The hardness measurement

is performed by using a spherical indentor. The hardness is given by measuring the

difference in penetration depth of the indentor between a small contact force and a large

force applied on the sample [50]. The penetration is then converted to IRHD. Tables for

this can be found in SS-ISO 48.

The change in hardness, ΔH, before and after aging or fuel exposure is calculated by

(4)

Where

ΔH0 = the initial hardness

ΔHi = the hardness after aging or immersion

Hardness was measured with a Bareiss digitest hardness tester (IRHD micro), according

to method M (microtest) in SS-ISO 48, measuring the hardness over 30 seconds. For

measurements on unexposed material, five readings were conducted. For fuel exposed

and aged materials, three readings on three different test pieces were performed.

Measurements on hoses were conducted both on the inside and outside of the hose, see

Figure 15. The measurements took place about 24 h after terminating the exposure.

23

a) b) c)

Figure 15. Hardness measurements. a) Measuring the inside of hose, b) outside of hose c) the hardness tester

3.6.3 Tensile testing

In tensile testing, a dumbbell is clamped in a tensile testing machine and stretched at a

uniform speed until it breaks. The force needed to stretch the sample and the extension

of the sample is recorded. By dividing the force with the initial cross section area, the

tensile stress, σ, is obtained:

(6)

Where

F = the force [N]

A = the cross section area [mm2] of the narrow part of the dumbbell.

The maximum tensile stress during measurement to rupture, is called tensile strength,

see Figure 16a).

The extension per unit length is called elongation or strain, ε, and is calculated by

(7)

Where

L = the measured extension

L0 = the original length of the narrow part of the dumbbell.

The elongation at rupture is called elongation at break, εB, see Figure 16a).

24

a) b)

Figure 16. Tensile testing. a) example of stress-strain curve for a rubber indicating tensile strength and elongation at break, b) Tensile tester used for testing. Tensile testing was carried out with an Alwetron TCT 50 tensile tester with a load cell of

500N, see Figure 16b). A pretension of 0.5N and a test speed of 500mm/min were used.

For unexposed and aged samples, five dumbbells were used. For fuel exposed samples,

3-4 dumbbells were used. Measurements were performed about 24h after terminating

the exposure.

When conducting tensile testing of hose_16 after 168h at 115°C in B7, the temperature

in the lab was elevated and ~4°C higher than normal.

3.6.4 Compression set

Compression set is used to measure the ability of a rubber to recover from an applied

compression. Test pieces and spacers are placed between two steel plates that are

tightened. The thickness of spacers determine the compression the test pieces will be

subjected to, for rubber with hardness 10-95 IRHD a compression of 25% is normally

used [51]. After exposure, the test pieces are released and the thickness of the samples is

measured after recovering at room temperature for a given time, see Figure 17. The

compression set, CS, is calculated by

(8)

Where

h0 = the initial thickness

h1 = the thickness after recovery

hs = the thickness of the spacers used.

25

As can be seen in equation 8, test pieces that recover fully have a CS of zero, while test

pieces that do not recover have a CS of 100%.

Figure 17. Compression set. A test piece (black) is placed between two steel plates that are screwed together, a spacer is used (light grey). After disassembling the equipment, test pieces are left for recovering before measuring the thickness. For compression set, equipment like the ones in Figure 18 a-b) was used. Three circular

discs were piled up, forming one sample, with a total height of approximately 6mm, see

Figure 18 c). Spacers were chosen so that the compression of each sample was 25 2%.

For aging, CRC Silicone lubricant was sprayed onto the steel plates as release agent. For

exposure in fuel, the equipment was immersed in fuel. For aging, the equipment was

placed in the bottom of the cells in the oven. At the end, the equipment was left to cool

down for 75 15 min (method B in SS-ISO 815) before it was disassembled. Test pieces

were then left to recover for 30 minutes before the thickness was measured.

For exposures performed by SP, the cooling time was ~120 min. PTFE spray was used as

release agent.

Five test pieces were used for aging and three test pieces were used for exposure in fuel.

Compression set was performed on samples from rubber sheets and not on hoses.

Figure 18. a) and b) equipment for compression set, c) three piled up discs forming one sample.

3.6.5 FTIR

Fourier transform infrared spectroscopy (FTIR) is used to measure how much a sample

absorbs infrared radiation, it gives information on the molecular bonds present in the

sample. A bond between atoms in a molecule can be assumed to be a spring that can be

bent and stretched, this is referred to as vibrations. If incoming infrared radiation has

the same frequency as the vibration of the molecule, it can be absorbed. Only molecules

26

having an electric dipole moment that changes during the vibration can show infrared

absorption [52]. Infrared spectra are complex due to the many vibrations coupling over

the entire molecule. There is a region in the infrared spectrum, below around 1500cm-1,

that gives information about the molecule as whole and is useful when identifying a

material, this is called the fingerprint region.

For some samples, like rubber, reflection techniques are used along with FTIR. In

attenuated total reflectance (ATR) spectroscopy, the sample is placed on a crystal. The

beam is reflected in the crystal and penetrates a small portion of the sample where some

radiation is absorbed, the remaining signal is detected [52]. ATR-FTIR is an easy-to use

and fast method where no advanced sample preparation is needed.

FTIR analysis was performed with a PerkinElmer Spectrum 100 with uATR (universal

ATR) between 4000 and 650cm-1 with a resolution of 4cm-1 and 4 scans, see Figure 19.

Unexposed rubber, aged and fuel exposed rubber for 1008h and all fuels were analyzed.

For black rubber, a Ge-crystal was used due to the high absorption of carbon black. Ge

has a high refractive index which allows deeper penetration of radiation into the

material. For fuels and green rubber, a diamond/ZnSe crystal was used. For rubber

samples from sheets, FTIR was conducted on a new cross section. For hoses, the inner

and outer layer was pulled apart. Analysis was conducted on the inside, outside, inside

towards reinforcement and outside towards reinforcement, see Figure 19.

Figure 19. a) Cross section of fuel hose. FTIR was performed on the inside, outside, inside towards reinforcement and outside towards reinforcement. b) uATR-FTIR equipment.

a) b)

27

4 Results and discussion The initial properties of unexposed materials are presented in Table 7. The properties

are presented as medians of the performed measurements on five specimens per

material, and were used as initial values when calculating the changes in properties after

aging and fuel exposure. The thickness of the hoses is different from samples prepared

from sheets. Sheets and hoses have also been processed differently which affects the

mechanical properties. Results for hoses are therefore not comparable with material 1-

13.

Table 7. Initial properties of rubber components expressed as median values. Material Thickness

(mm) Hardness (IRHD)

Tensile strength (N/mm2)

Elongation at break (%)

NBR_1 1.94 68 16.08 697.70

NBR_2 1.95 73 17.01 494.90

NBR_3 1.96 72 18.79 518.30

HNBR_4 1.95 72 21.75 382.10

HNBR_5 1.90 73 18.42 382.00

AEM_6 1.96 76 15.17 455.30

AEM_7 1.94 72 15.59 396.40

AEM_8 1.90 38 10.04 705.50

AEM_9 1.90 48 14.36 724.90

FKM_10 1.95 73 13.72 374.60

FKM_11 1.94 74 18.91 518.70

FKM_12 2.00 75 16.36 459.20

FKM_13 1.95 69 23.63 700.30

hose_14 3.76 61 (inside)

55 (outside) 10.46 300.40


54 (outside) 10.80 420.70


57 (outside) 5.71 483.00

Results for fuel exposed and aged materials are expressed as averages. The medium,

time and temperature for exposure are designated XYhZC where X is B (B100), D (B7), E

(ED95) or A (air). Y is the time for the exposure expressed in hours (h) and Z is the

temperature expressed in °C (C).

Results are presented as bar charts with error bars ( 1 standard deviation) or as tables.

When discussing the results, the terms small, minor, moderate and severe will

sometimes be used. The meaning of these terms is explained in Table 8. Small to

moderate effects indicates that the rubber still can be used in at least some applications,

while severe effects indicates that the deterioration will be too large to be used in that

fuel. The division of criteria are based on recommendations in SAE international

standard SAE J30, the classifications according to Table 3 and experience on Scania.

28

Table 8. Terms used when discussing the results. The change is expressed as % change from initial value.

Term Volume change (%)

Hardness change (IRHD units)

Change in tensile strength (%)

Change in elongation at break (%)

Compression set (%)

Small 0 - 5 0-5 <10 <10 0-15

Minor 5 - 15 5-10 10-25 10-25 15-30 Moderate 15 - 40 10-25 25-55 25-55 30-70

Severe > 40 >25 > 55 > 55 > 70

4.1 Visual observations

After all 1008h exposures in fuel, pictures were taken to see visible changes in color and

volume. In B100, Figure 20, all samples have swelled. NBR_2 seemed to have swelled the

most, while least swell was observed for NBR_3.

Figure 20. Fuel exposed samples in B100, 168h at 115 °C. Unexposed samples lie to the left of the exposed sample. Swell is visually observed for all samples. NBR_2 seems to have swelled the most. NBR_3 seem to have swelled the least.

29

In B7, Figure 21-22, swell was visually observed for all samples. At the lower

temperature, most swell was observed for HNBR_5 and least swell was observed for

NBR_3. At the higher temperature, AEM_7 had swelled the most. A slight color change

was seen for FKM_10.

Figure 21. Fuel exposed samples in B7, 1008h at 105 °C. Unexposed samples lie to the left of the exposed sample. Swell is visually observed for all samples. HNBR_5 seems to have swelled the most, NBR_3 seems to have swelled the least.

Figure 22. Fuel exposed samples in B7, 1008h, 135°C. Unexposed samples lie to the left of the exposed sample. Swell is visually observed for all samples. AEM_7 seems to have swelled the most. FKM_10 has become darker.

30

In ED95, swell was observed for all samples, see Figure 23. AEM_7 swelled the most

while NBR_2 and NBR_3 swelled the least.

Figure 23. Fuel exposed samples in ED95 for 1008h at 70°C. Unexposed samples lie to the left of the exposed sample. Swell is visually observed for all samples except for NBR_2. AEM_7 seems to have swelled the most.

4.2 FTIR analysis

All FTIR spectra can be found in Appendix A and only some examples will be shown

here. A discussion on the analysis of unexposed samples is also found in Appendix A. All

spectra have been background corrected. FTIR spectra are generally quite complex and

hard to interpret. When studying spectra, focus has been on identifying whether any

additional peaks or intensity reduction of peaks can be seen. After exposure in fuel,

some additional peaks, consistent with peaks for the fuel used, can be seen in most

materials. This is expected due to absorption of the fuel.

After exposures in B100

For all NBR exposed to B100, additional peaks can be observed at 1740 (C=O), 1245 (C-

O), 1195 (C-O) and 1170 cm-1 (C-O) after exposure. These signals can all be related to

bonds present in B100 and it is probable that it is signals from bonds present in esters.

From FTIR analysis of NBR, the signal associated with the C-O bond at ~1100cm-1 is

reduced for both NBR_1 and NBR_2. It is possible that this might be due to the extraction

of ether (used as softener), see Figure 24.

For NBR_3, signals at 1260, 1130, 1040 and 810 cm-1 has been reduced. The first three

might be related to P=O and P=OR ester and the one at 810 cm-1 to C-H stretches in

aromatics. This might be related to the extraction of softener.

31

Additional peaks at 1245, 1195 and 1170 cm-1 can be observed in all the HNBRs, all

these related to B100. For HNBR_4 an additional peak at 1740cm-1 is seen,

corresponding to the ester groups in B100. Apart from fuel absorption, all signals seem

to be reduced after exposure both for HNBR_4 and HNBR_5, but this might be to a low

signal during the measurement. Apart from that, no changes can be seen for any of the

HNBRs.

For hose_15, additional signals, corresponding to B100, at 1245, 1195 and 1170 cm-1 can

be observed. For the inside towards reinforcement, a signal at ~800cm-1 seems to have

been reduced. This could be a C-H stretch for aromatics that might be present in a

softener. No changes can be seen for the inside. For the outside and outside towards

reinforcement, signals at ~1240, 1110 and 1070 cm-1 are reduced. These could be C-O

bonds in ethers, indicating the extraction of softener.

FTIR spectra of hose_16 also show absorption of B100, due to the additional signals

observed at 1245, 1195 and 1170 cm-1 after exposure. A slightly reduced signal is

observed at 1110 cm-1 for both the outer and inner layer, which could correspond to C-O

bond in ether used as softener.

Figure 24. FTIR spectra of NBR_2 before and after exposure in B100 for 168h at 115⁰C. On the top is the spectrum for pure B100. A peak around 1100cm-1 has been reduced which might be related to ether.

Emmy_B100_diamant_1Emmy_ref#2_1Emmy_B168h115gr#2_1

NameBiodiesel, RME. Artnr. 1546061-31oexp NBR, artnr 6370084B100 (RME) exponerad NBR, artnr 6370084, 168h, 115gr

Description

B100 exposed #2NBR, 168h, 115C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660

65

70

75

80

85

90

95

%T

85

70

72

74

76

78

80

82

84

%T

91

83

84

85

86

87

88

89

90

91

%T

B100

Unexposed #2 NBR

Exposed #2 NBR

1102cm-179,535%T

1088cm-190,016%T

32

After exposures in B7

For all NBR exposed to B7, an additional signal at ~1745cm-1 is observed. This signal is

also shown for B7, indicating that fuel has been absorbed. NBR_1, NBR_2 and NBR_3

shows the same changes in B7 as in B100, if one do not take in to account the absorption

of fuel. As discussed earlier, this might be due to the extraction of softeners.

For HNBR_5, no additional signals due to B7 can be seen, but this is probably because

many equal bonds are represented in both the rubber and fuel, signals may therefore

overlap. The overall signal is, just as in B100, reduced. Even if the overall signal is

reduced, decreased signals are observed at ~1730, 1460 and 1170cm-1 after exposure.

This might be connected to extraction of softener since these are C-O bonds present in

ester.

For AEM_7, no visible changes more than absorption of B7 is seen. The absorption of B7

can be observed around 3000cm-1 where a shoulder, rising from B7, is seen on the signal

around 3000cm-1 for AEM.

For FKM, the absorption of B7 can be observed around 3000-2250cm-1. Otherwise, no

visible changes are seen.

For hose_14 a reduction of signal at ~800cm-1 is seen for the outside. It could be C-H

bonds present in aromatic groups in softener, indicating extraction of softener.

Just as for HNBR_5, the absorption of B7 is not seen in hose_16, but it might be due to

overlap of signals. A signal seems to have disappeared at 1260cm-1 in all layers, it could

be C-O bonds in ester or ether.

After exposure in ED95

FTIR analysis of ED95 show several peaks, the largest being at ~3330 (OH), 2973 (CH

stretch), 1087 (C-O), 1045 (CO) and 880 cm-1. These all seems to correlate well with the

structure of alcohol or the additives present.

For all NBR, the absorption of ED95 can be seen as additional peaks after exposure,

corresponding to the wave numbers above. For NBR_1 and NBR_2, decreased signals at

~965 (=C-H in alkanes) and 910 cm-1 (=C-H) is seen. It can be that the double bonds

have been chemically attacked, or it can be due to low signal during measurement. For

both NBR_1 and NBR_2, the peak at ~1100cm-1 (C-O) has disappeared or is overlapped

by ED95, it can be due to the loss of softener.

For NBR_3, peaks at 1260 and 1130cm-1 has disappeared. As discussed above, these

peaks correlate with the phosphate softener used indicating loss of softener.

Additional peaks corresponding to ED95 is seen in HNBR_5. Peaks at ~1730 (C-O), 1460

(CH2 or CH3) and 1160cm-1 (C-O) are reduced, just as in B7, indicating loss of softener.

33

Additional peaks in AEM_7 can all be related to ED95. Loss of signal at ~1730 (C-O),

1430 (C-C), 1195(C-O), 1160 cm-1(C-O) is seen. It can probably be related to the loss of

adipate used as softener.

For FKM_10 the only change seen is the additional peaks from uptake of ED95. For

FKM_11, apart from the absorption of ED95, the peak corresponding to C-F at

~1100cm-1 seems to be reduced and shifted towards lower numbers. But the overall

signal also seems to be reduced. For FKM_13 no change more than absorption of ED95

can be seen.

For hose_14 additional peaks for ED95 are seen. The inside towards reinforcement

seems to be unaffected, for the inside a displacement of the peak C-F peak around

~1100cm-1 towards lower wave numbers is seen, that peak also seems to be slightly

reduced. This was also observed for FKM_11. It might be that ED95 overlaps in that

region. For the outside towards reinforcement a peak at ~1250cm-1 (C-O) is reduced, for

the outside no changes can be seen.

A loss of peak is observed for hose_16 at 1260cm-1, which can be C-O stretch. Additional

peaks corresponding to ED95 is observed in all layers.

After aging in air

For NBR_2, all HNBRs, all AEMs and FKM_10-12 no changes can be seen after aging.

NBR_1 has additional peaks at 1580 and 1560cm-1, both correspond to C-O bonds.

For NBR_3 a change in the region 1290-1160cm-1 is seen. This region is the same that

showed signal for phosphor containing groups for unexposed samples. Since it was

visually observed that migration of additives had occurred after aging, it might be

related to loss of softener.

For FKM_13 a slight reduction in signal for the C-F peak at ~1160cm-1 is seen.

For hose_14, the outside towards reinforcement shows decreased signals at ~860 and

800cm-1. For the outside, reduced signals are observed in the region 1690-1490cm-1.

After aging at 105°C of hose_15, the outside towards reinforcement gives additional

signals at 1580cm-1. After aging at 135 °C a loss of signal at ~975cm-1 (=C-H) is observed

for the outside towards reinforcement. The outside seems to have been more affected

since additional peaks are observed at ~1600, 1497, 1153 cm-1 and reduced signals are

observed at ~1120, 1070, 1017, 870cm-1.

For the inside of hose_16 a broadening of the peak at ~1090cm-1 and increased signals

for peaks at ~1050 and 1015cm-1 is seen.

34

4.3 NBR materials

Bar charts for measured properties for NBR after exposure to fuel are presented in Figure 26, and after aging in air in Figure 27. To visualize the general performance, measured properties has been divided into the classes according to Table 8, see Table 9. If the material show one change in property and compression set that is severe for that exposure, the material is probable less appropriate in that fuel or in air. Table 9. Properties for NBR. Color indicating the classification of property: white = small, green= minor, yellow = moderate, red= severe.

Property Material B168h D168h D504h D1008h E504h E1008h E168h A168h A504h A1008h 115C 115C 105C 105C 70C 70C 115C 115C 105C 105C


NBR_1 -17 -9 -7 -9 -6 -7

+10 +13 +19 NBR_2 -27 -20 -21 -18 -3 -3

+8 +9 +17

NBR_3 -13 -4 -3 -3 -2 -4

+6 +8 +18 Volume change (%)

NBR_1 +29.3 +10.4 +9.5 +10.2 +13.2 +13.5

NBR_2 +69.9 +23.5 +24.1 +24.0 +4.7 +5.0

NBR_3 +20.5 +5.6 +5.7 +5.7 +6.5 +5.4


NBR_1 -6.5 +3.1 -53.1 -64.0 -17.3 -22.5

+12.0 +13.8 +22.7 NBR_2 -45.3 -31.3 -85.0 -27.7 -11.0 -19.3

-15.1 -1.9 -5.7

NBR_3 -12.9 -24.8 -12.4 -14.3 -12.5 -15.8

-15.4 -8.6 -7.5 Change in elongation at break (%)

NBR_1 -7.6 -4.2 -57.8 -62.5 -20.2 -30.5

-33.0 -39.8 -66.3 NBR_2 -53.2 -18.2 -78.6 -12.3 -8.6 -17.3

-48.2 -52.2 -79.6

NBR_3 -5.7 -22.5 -16.1 -15.8 -13.6 -17.9

-36.1 -35.0 -68.1 Compression set (%)

NBR_1 +0.9 +25.8 +35.6 +43.1

+46.0 +45.4 +62.4 +71.3 NBR_2 -19.3 10.9 +24.7 +26.7

+33.8 +41.1 +61.6 +72.4

NBR_3 +9.2 +23.1 +32.9 +34.9

+24.0 +29.9 +51.4 +66.1

It is generally seen that volume change and hardness change seems to be associated. A high swell is followed by a high decrease in hardness. This is due to plasticization of the material when fuel is absorbed. In air, an increased hardness is observed with time, maybe due to loss of softener or additional cross linking. For NBR_3, droplets could be seen on the surface of samples after 504h and 1008h in air. This is probably the phosphate based softener that has migrated. Volume change In B100 and B7 it is seen that NBR_2 swell more than the other NBRs. This might be due to the lower ACN content (21% compared to ~30% for NBR_1 and NBR_3) as mentioned in the theory section. A lower ACN content gives the rubber a lower polarity which makes it swell more in B100 and B7. The ACN content might also be the reason why NBR_1, with a higher ACN content, swells more than NBR_2, with a lower ACN content in ED95. ED95 is more polar than both B100 and B7. Mechanical properties The most obvious trends are that NBR_2 is most affected in mechanical properties (tensile strength and elongation at break) in B100 of the NBRs. In B7, crack formation was observed for NBR_1 during tensile testing, see Figure 25. The mechanical properties were also severely affected after 1008h. All NBR materials show acceptable mechanical properties in ED95.

35

After aging in air, the elongation at break seems to be severely affected with time for all NBRs, with NBR_2 showing the largest decrease. The mechanical properties of NBR_2 after 504h in B7 are unusually affected, which cannot be explained. Comparison of FTIR spectra for NBR_2 after 504h and 1008h show no apparent difference. Maybe an erroneous measurement by the tensile testing machine is the reason.

Figure 25. Severe crack formation during tensile testing of NBR_1 after exposure in B7. Note: the sample on the picture is stretched out.

Compression set Compression set gives an indication of the sealing ability. Negative compression set is observed in B100, which can be related to a high volume swell [53]. Even though the compression set is low, the severe swell will probably affect the sealing ability. The compression set seems to increase with time in both B7 and air. Concluding remarks for NBR materials The long-term aging resistance in air of NBR seems to be poor. However, if the

rubber article is immersed in fuel, the influence of oxygen is minor. NBR might still be used in contact in air during shorter times, probably at least 20 000h, since no changes are severe after 504h.

All NBRs show moderate to severe swell in B100, but the mechanical properties for NBR_1 and NBR_3 are still good. This still makes them being possible materials for shorter periods in B100, provided that the service temperature is low, since the swell will probably decrease. Further testing is recommended. NBR_2 is not recommended at all in B100.

In B7, NBR_3 seems to be the best choice to reach the wished life time of 40000h, and higher temperatures during shorter periods do not seem to affect.

All NBRs are potential materials for use in ED95, at least for short term use at lower temperatures. Further testing is recommended at higher temperatures to see the long term effects.

36

Figure 26. Measured changes in volume, hardness, tensile strength, elongation at break and compression set for the different types of NBR in fuels. The error bars represents standard deviation.

0

10

20

30

40

50

60

70

Vo

lum

e c

han

ge (

%)

Volume change NBR in fuels

NBR_1 NBR_2 NBR_3

-40

-30

-20

-10

0

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change NBR in fuels

NBR_1 NBR_2 NBR_3

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength, NBR in fuels

NBR_1 NBR_2 NBR_3

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break, NBR in fuels

NBR_1 NBR_2 NBR_3

-40 -30 -20 -10

0 10 20 30 40 50 60

Co

mp

ress

ion

se

t (%

)

Compression set NBR in fuels

NBR_1 NBR_2 NBR_3

37

Figure 27. Measured changes in hardness, compression set, tensile strength and elongation at break for the different types of NBR aged in air. The error bars represents ±1 standard deviation.

-20

-10

0

10

20

30

A168h115C A504h105C A504h135C

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change aged NBR

NBR_1 NBR_2 NBR_3

0

10

20

30

40

50

60

70

80

90

100

A168h115C A504h105C A1008h105C

Co

mp

ress

ion

se

t (%

)

Compression set aged NBR

NBR_1 NBR_2 NBR_3

-30

-20

-10

0

10

20

30

A168h115C A504h105C A1008h105C

Ch

ange

te

nsi

le s

tre

ngt

h (

%)

Change tensile strength aged NBR

NBR_1 NBR_2 NBR_3

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

A168h115C A504h105C A1008h105C Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break aged NBR

NBR_1 NBR_2 NBR_3

38

4.4 HNBR materials

Bar charts for measured properties for HNBR after exposure to fuel are presented in

Figure 28, and after aging in air in Figure 29. A table with colors indicating the classes of

changes can be found in Appendix B.

It is generally seen that the degree of decrease in hardness after exposure in B100 is

related to volume swell. It is also found that HNBR_4 has better aging resistance than

HNBR_5. This can be due to the fully saturation of HNBR_4 which makes it less

vulnerable to chemical attack as described in the theory section.

Volume change

Both HNBR_4 and HNBR_5 show high swell in B100, but HNBR_5 swells considerably

more than HNBR_4. This can probably be related to the fact that HNBR_5 has a lower

ACN content compared to HNBR_4. In B7 and ED95, HNBR_5 show moderate swell.

Mechanical properties

Mechanical properties in fuels are generally minor to moderate with exception for

HNBR_5 in B100 where severe changes are seen. A deterioration of mechanical

properties with higher temperatures in air is seen for HNBR_5.

Compression set

A negative compression set is observed for HNBR_5 in B100, due to severe swelling.

Compression set increases with time and temperature in air. The compression set of

HNBR_5 in air is severe at 135°C (~90%).

Concluding remarks on HNBR materials The aging resistance in air of both HNBRs seems to be good enough to achieve the

wished life time of 40000h in applications with lower temperatures, even if the

temperature is raised for shorter periods. At higher temperatures, HNBR_4 can be

used while HNBR_5 is not recommended where low compression set is needed.

For use in B100, HNBR_4 might be an alternative provided that the service

temperature is low. The change in tensile strength is however high (~50%) so

further tests are needed. HNBR_5 is not recommended at all in B100.

HNBR_5 is a possible material for use in ED95 in applications with lower

temperatures. The swell is quite high, even though the temperature is only 70°C. It

will probably swell even more at higher temperatures.

HNBR_5 might be used in B7 for long-term use and does not seem to be negatively

affected by higher temperatures at shorter times. The short term exposure of 168h at

150°C indicates that HNBR_5 may also be used in applications at higher

temperatures for shorter times as an alternative to more expensive materials like

FKM.

Theoretically HNBR_4 should have better fuel resistance in B100 and B7 than

HNBR_5 due to its higher saturation and ACN content [9]. The low temperature

properties of HNBR_4 are a risk because the glass transition temperature is around

-20°C, which makes it a less good choice.

39

Figure 28. Measured changes in volume, hardness, tensile strength, elongation at break and compression set for the different types of HNBR in fuels. The error bars represents standard deviation.

0

10

20

30

40

50

60

70

Vo

lum

e c

han

ge (

%)

Volume change HNBR in fuels

HNBR_4 HNBR_5

-40

-30

-20

-10

0

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change HNBR in fuels

HNBR_4 HNBR_5

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength, HNBR in fuels

HNBR_4 HNBR_5

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break , HNBR in fuels

HNBR_4 HNBR_5

-40 -30 -20 -10

0 10 20 30 40 50 60

Co

mp

ress

ion

se

t (%

)

Compression set HNBR in fuels

HNBR_4 HNBR_5

40

Figure 29. Measured changes in hardness, compression set, tensile strength and elongation at break for the different types of HNBR after aging in air. The error bars represents ±1 standard deviation.

-20

-10

0

10

20

30

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change aged HNBR

HNBR_4 HNBR_5

0 10 20 30 40 50 60 70 80 90

100

Co

mp

ress

ion

se

t (%

)

Compression set aged HNBR

HNBR_4 HNBR_5

-30

-20

-10

0

10

20

30

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength aged HNBR

HNBR_4 HNBR_5

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break aged HNBR

HNBR_4 HNBR_5

41

4.5 AEM materials

Bar charts for measured properties for AEM after exposure to fuel are presented in



The hardness measurements of AEM_6 and AEM_7 after aging in 135°C showed large

spread leading to high standard deviations. This might be due to variations in the

materials. For AEM_8 the hardness was too low to be measured. The hardness tester

only measures down to 28 IRHD.

Once again, a high swell is accompanied with a high decrease in hardness due to

plasticization of the material. Generally AEM seem to have a good aging resistance.

Volume change

In B7, the volume decreases with time. This can be due to the extraction of additives and

low molecular species. The volume change in B7 is moderate, the volume change in

ED95 is severe, above 50%. This indicates that AEM_7 and ED95 have a polarity close to

each other.


The largest changes in mechanical properties are seen in tensile strength for AEM_7 in

ED95 (~ -50%). In air, the changes in mechanical properties are generally low.

Compression set

A negative compression set is observed for AEM_7 in ED95 due to its severe swelling.

The compression set in B7 and in air increases with time. AEM_6 has the highest

compression set in air and is classified as severe after 1008 h.

Concluding remarks on AEM materials

It is a difference between the different AEMs in air, but no general trend can be seen

between the different properties, therefore no conclusions on aging resistance based

on the different compositions can be given.

AEMs have good aging resistance and are appropriate in applications with higher

temperatures for long term use, the whole wished life time, even when the

temperature is elevated at shorter periods. If however compression set is an

important property, AEM_6 is not recommended.

AEM_7 is a possible material to reach the wished life time in B7 and seems to

withstand elevated temperatures.

AEM is not recommended in ED95 due to the severe swell.

42

Figure 30. Measured changes in volume, hardness, tensile strength, elongation at break and compression set for the different types of AEM in fuels. The error bars represents ±1 standard deviation.

0

10

20

30

40

50

60

70

Vo

lum

e c

han

ge (

%)

Volume change AEM in fuels

AEM_7

-40

-30

-20

-10

0

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change AEM in fuels

AEM_7

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength, AEM in fuels

AEM_7

-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break, AEM in fuels

AEM_7

-40 -30 -20 -10

0 10 20 30 40 50 60

Co

mp

ress

ion

se

t (%

)

Compression set AEM in fuels

AEM_7

43

Figure 31. Measured changes in hardness, compression set, tensile strength and elongation at break for the different types of AEM aged in air. The error bars represents ±1 standard deviation.

At least -10

-8 At least -

10 -20

-10

0

10

20

30

A168h165C A504h135C A1008h135C

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change aged AEM

AEM_6 AEM_7 AEM_8 AEM_9

0

10

20

30

40

50

60

70

80

90

100

A168h165C A504h135C A1008h135C

Co

mp

ress

ion

se

t (%

)

Compression set aged AEM


-30

-20

-10

0

10

20

30

A168h165C A504h135C A1008h135C

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength aged AEM


-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

A168h165C A504h135C A1008h135C Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break aged AEM


44

4.6 FKM materials

Bar charts for measured properties for FKM after exposure to fuel, are presented in



The main difference between the four types of FKMs tested in fuel is the polymer type,

according to ASTM D1418, and curing system used. FKM_10 is of type 1 (bisphenol

cured), FKM_11 is of type 3 (peroxide cured), FKM_ 12 is of type 2 (bisphenol cured) and

FKM_13 is of type 2 (peroxide cured), explanations are given in section 2.1.1. One

important difference is also the differences in fluorine content.

Overall, FKMs seem to have good resistance to both B7 and air. In ED95, changes are

slightly larger. Hardness change is also consistent with volume change in ED95.

Volume change

The volume increase is larger in ED95 compared to B7, even though the temperature is

lower in ED95. FKM_11 swells the least in ED95 while FKM_10 swells the most. Volume

increase in B7 is small for all materials


It is mainly the tensile strength that is reduced after exposures in ED95, the change is

equal for all types. NBR_11 show the largest decrease in tensile strength in B7. For

elongation at break, changes are generally small in both B7 and ED95. In air, changes in

mechanical properties are generally small.

Compression set

In B7, compression set is smaller for FKM_10 compared to the others. The same is

observed in air. The other FKM seems to be quite equal

For FKM_10, severe chemical degradation was seen for compression set in ED95 at

150⁰C, see Figure 32. This was not observed for the other FKMs. The result implies that

at least FKM_10 is not suitable in applications with high temperature in contact with

ED95.

45

Figure 32. Severe degradation of FKM_10 after compression set in ED95 at 150°C for168h. Concluding remarks on FKM materials

All FKM show good resistance to aging in air and might be used the whole wished life

time of 40 000h, even if the temperature is elevated for shorter periods. If

compression set is of great importance for the application, FKM_10 is recommended.

All FKMs tested are also appropriate for use in B7, also at elevated temperatures and

have good possibility to reach the wished life time.

FKM_11 and FKM_13 (FKM type 3 and 2, peroxide cured) seems to be possible

materials for use in ED95.

FKM_10 (type 1, bisphenol cured) is not recommended due to the chemical

degradation shown during compression set measurements.

46

Figure 33. Measured changes in volume, hardness, tensile strength, elongation at break and compression set for the different types of FKM in fuels. The error bars represents ±1 standard deviation.

0

10

20

30

40

50

60

70

Vo

lum

e c

han

ge (

%)

Volume change FKM in fuels

FKM_10 FKM_11 FKM_13

-40

-30

-20

-10

0

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change FKM in fuels


-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

te

nsi

le s

tre

ngt

h (

%)

Change in tensile strength, FKM in fuels


-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break, FKM in fuels


-40 -30 -20 -10

0 10 20 30 40 50 60

Co

mp

ress

ion

se

t (%

)

Compression set FKM in fuels


47

Figure 34. Measured changes in hardness, compression set, tensile strength and elongation at break for the different types of FKM aged in air. The error bars represents ±1 standard deviation.

-20

-10

0

10

20

30

A168h165C A504h135C A1008h135C

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change aged FKM

FKM_10 FKM_11 FKM_12 FKM_13

0 10 20 30 40 50 60 70 80 90

100

A168h165C A504h135C A1008h135C

Co

mp

ress

ion

se

t (%

)

Compression set aged FKM


-30

-20

-10

0

10

20

30

A168h165C A504h135C A1008h135C

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength aged FKM


-90 -80 -70 -60 -50 -40 -30 -20 -10

0 10 20

A168h165C A504h135C A1008h135C

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break aged FKM


48

4.7 Hoses

Since the hoses consist of several layers, including a reinforcement, measurements give

information on the hose test piece as a whole and not the individual materials in the

layers. In real applications, hoses are not totally immersed in a fuel, which is worth to

keep in mind. There is however no easy and fast test method for assessing the lifetime of

hoses and immersion tests still give some indications of the suitability.

Due to the shape and thickness of samples from hoses, hardness measurements were

generally difficult to perform. But the measurements have been performed using the

same procedure and sample shape for all samples. For some measurements the

hardness fell below 28 IRHD, which is the hardness where the tester tops to measure.

Therefore hardness change is explained as “at least” for some measurements.

Hose_14 (FKM/ECO/AR/ECO)

The results for hose_14 are presented in Table 10, with colors indicating the classes of

changes. Bar charts are available in Appendix C.

Table 10. Properties for hose_14. Color indicating the classification of property: white = small, green= minor, yellow = moderate, red= severe.

Property Material D D D E E A A A 168h 504h 1008h 504h 1008h 168h 504h 1008h

hose_14 150C 135C 135C 70C 70gr 165C 135C 135C Hardness change (IRHD units)

inside -7 -1 -2 -8 -9 +5 +6 +4 outside

-8 -6 -7 -15 -19 +6 +4 10

Volume change (%)

+14.8 +13.1 +14.6 +16.9 +17.0


-25.0 -20.4 -33.8 -31.1 -29.9 -46.0 -23.7 -38.1


-31.8 -34.5 -44.5 -17.7 -13.1 -45.3 -27.6 -41.2

Hardness measurements show that the outside has a larger decrease in hardness

compared to the inside in all fuels. This indicates that the outside is affected more than

the inside by the fuel. The mechanical properties seem to be more affected by the short-

term aging in air at high temperature than the longer aging in air at lower temperature.

Hose_14 generally seems to show acceptable changes in B7 and air and seems to be a

possible hose to be used the whole wished life time. It is also a possible hose for use in

ED95.

49

Hose_15 (HNBR/CPE)




Property Material B A A A A A 168h 168h 504h 1008h 504h 1008h

hose_15 115C 115C 105C 105C 135C 135C Hardness change (IRHD units)

inside -18 +2 +2 +7 +9 +10 outside

At least -26 0 +6 +7 +22 +40

Volume change (%)

+38.8


n/a -7.0 +4.2 -13.4 -39.4 n/a


n/a -27.8 -27.7 -56.3 -84.0 n/a

The type of HNBR used is not known. The volume change is relatively high in B100. The

outside seems to have been affected most, which is seen in the large hardness decrease.

During tensile testing, the outside broke before the inside, whereupon no mechanical

properties could be measured.

The aging resistance is poor, especially the outside of the hose seem to be affected which

is seen in the hardness change. High temperatures seemed to degrade the outside even

more. The hose could easily be broken by hand and test pieces were too brittle to

perform tensile testing after 1008h at 135⁰C.

Due to hose_15 outside layer, it is likely that the hose will fail in B100 unless low

permeation through the inner layer can be ensured. The aging resistance is also poor

during longer times. The hose do however show acceptable aging resistance during

shorter service, maybe around 20 000h, at lower temperatures.

50

Hose_16 (NBR/CR)




Property Material B D D D E E A A A 168h 168h 504h 1008h 504h 1008h 168h 504h 1008h

hose_16 115C 115C 105C 105C 70C 70gr 115C 105C 105C Hardness change (IRHD units)

inside -25 -15 -16 -13 -4 -1 15 14 13 outside At least

-29 -16 -15 -10 -3 -2 15 19 30

Volume change (%)

36.6 13.6 14.9 13.4 -0.5 -0.2


-23.7 -33.0 -44.0 -37.8 -6.0 2.6 -12.4 -13.4 12.0


-3.8 -30.0 -49.0 -41.7 -12.8 -6.8 -54.3 -67.1 -83.6

In B100, it seems like the outside is more affected than the inside, even though the inside

also shows large decreases in hardness. The aging resistance of the outside also seems to

be worse than that for the inside.

Overall it seems like hose_16 may be appropriate in B7 and ED95 but not in B100. The

long term aging resistance is poor, but the hose might be used for shorter periods.

Concluding remarks on hoses

Other tests than complete immersion in fuel are recommended for the hoses, especially

if these are built of layers of different materials. The results do not tell so much of the

actual performance since the outside (which seems to be the one that fails) will not be

immersed in fuel in reality.

51

4.8 Comparison between polymer types

The test in B100 shows that both NBR and HNBR exhibit high swell. The swell is reduced

with higher ACN content. NBR with a higher ACN content is generally7 slightly better

than HNBR with a higher ACN content.

In ED95, NBR is generally better than HNBR which exhibit higher swelling (even

compared to NBR_2 that has a similar ACN content, 21% compared to 19% for HNBR_5).

AEM swells considerably most of all of the materials. NBR is generally also better than

all FKMs tested.

For applications in B7 at lower temperatures, NBR_3 seems to be the suitable material.

There is a clear difference between the different NBRs. NBR with higher ACN content is

better than low ACN content. The same would probably have been seen for HNBR. When

comparing NBR_2 and HNBR_5, NBR_2 is slightly better in most cases.

For applications in B7 at higher temperatures, FKM is better than AEM, but none of them

show severe changes. When comparing short time exposures (168h) at 150°C, HNBR_5

might be used for shorter periods at higher temperatures if a high swell (~30%) is

accepted. It is possible that HNBR_4 could be an even better alternative due to its higher

ACN content and saturation, but as stated before, the low temperature properties are

worse.

For aging in air at lower temperatures it is evident that HNBR has a better aging

resistance than NBR, which is expected since some double bonds have been removed.

For aging in air at higher temperatures, both AEM and FKM show good resistance (with

exception for AEM_6), but FKM is generally better than AEM. HNBR_4 also showed good

aging resistance in air at 135⁰C and might be a good alternative at higher temperatures

in air.

7 The term “generally” means that when classifying the changes in properties and compression set according to Table 8, several of the properties have been better or worse compared to the other.

52

4.9 Testing in B100

A distinct color change of B100 could be seen after 168h at 115⁰C, see Figure 35. This

indicates degradation of fuel. Therefore, the results might not represent the actual

performance in B100 since the degradation products can have had a negative impact on

the rubbers. Testing in autoclaves would give information on how B100 itself affect the

materials. But since the presence of oxygen also is known to affect B100 largely, it is not

easy to find a good way for performing accelerated tests. Continuous exchange of fuel

would be necessary.

Figure 35. Comparison of color of B100 after exposure of samples 168h at 115⁰C. Unexposed fuel can be seen leftmost.

4.10 Reflections

Since the materials were commercial materials, the exact recipes were not known. More

conclusions may have been drawn of the composition and fuel resistance if the materials

were customized.

The test matrix in this diploma work was large. Maybe it would have been better to

focus on fewer materials and made more tests, like stress-relaxation, which gives more

information on the compression set. The adhesion properties between layers in hoses

would also give additional information.

For several of the tests in fuel, changes in properties are almost the same after 504h as

after 1008h. Maybe tests at 504h are enough for a first estimation of the suitability of the

material.

53

5 Conclusions The performance of rubber materials in fuels depends on several factors like polymer

type, curing system, types of softeners used etc. and the nature of the fuel. The ACN

content in NBR and HNBR and the degree of saturation of polymer seems to be of great

importance in at least B7 and B100. The type and composition of FKM has proven to be

of particular importance for use in ED95 where a type 1, bisphenol cured, FKM showed

severe chemical degradation during compression set at 150⁰C.

When comparing the different rubber groups it is seen that NBR has poorer aging

resistance in air compared to the other polymer types. In ED95, AEM swells

considerably more than any of the other rubbers, while NBR seems to be the best choice

of the different rubber groups in low temperature applications. In B100, NBR show

slightly better performance than HNBR, but both show high swelling. For use in B7, at

higher temperatures, FKM is better than AEM.

The following has been concluded on the potential of the different rubber materials to

be used in the different fuels tested:

For use in B100: NBR and HNBR with an ACN content of ~30%, might probably be

used in B100 for shorter periods at lower temperatures, but further tests are needed.

For use in B7 at lower operation temperatures: Of the three NBRs tested, one

have the best possibility to reach the whole wished life time of 40 000h. It has an

ACN content of 29.5% and 10% phosphate based softener. The HNBR that was tested

(21% ACN) might also be used.

For use in B7 at higher operation temperatures: Of the four FKM tested, all types

are suitable for use in B7, all the way up to the wished life time. AEM (Vamac GLS)

show high swell (15-20%) in B7, but have good mechanical properties, therefore still

being a possible alternative and might reach the whole wished lifetime. HNBR might

be used for shorter periods.

For use in ED95: All of the NBRs tested have a good potential to be used, especially

one type with a lower (19%) ACN content. HNBR might also be used at lower

temperatures. The type of FKM was shown to be of great importance, FKM type2 and

3 (bisphenol cured) might be used. AEM is not recommended.

Aging resistance in air: HNBR, AEM and FKM show good aging resistance, probably

all the way up to the wished life time. NBR does not have sufficient aging resistance

all the way up to the wished life time, but for shorter periods.

The performance of hoses, based on complete immersion in fuel, is hard to predict. It

seems like it might be the outer layer that is affected the most during exposure. The

hose of FKM/ECO/AR/ECO have the possibility to reach the wished life time for use

in B7, ED95 and air.

Even though the hose of NBR/CR show acceptable performance in both B7 and ED95

all the way up to wished life time, its poor aging resistance might cause it to fail early.

Poor aging resistance for hose of HNBR/CPE might also cause premature failure.

54

6 Further work First of all, the combination of presence of air together with fuel would be valuable, since

oxygen is continuously available in the fuel system. Some oxygen was available in the

autoclaves since they were not completely filled, but the amount of oxygen was not

controlled and not supplied continuously. By mixing the fuel with controlled amounts of

air, mimicking real service conditions, more valuable information would be given.

It is advisable to collect data for Arrhenius extrapolations for at least one material to see

if there is a linear behavior.

Since the tests in B100 could not performed as planned, further investigations on how to

test in B100 is recommended. A good start is to perform tests in autoclaves to see how

B100 itself affect.

It would be interesting to compare samples from field with laboratory tested samples to

see if accelerated tests give relevant information on actual performance. Another

alternative would be to conduct the accelerated tests under more close-to real

conditions. For hoses it could for example be an experimental setup where fuel is

circulated so that only the inside comes in contact with fuel.

To study the effect of temperature when testing in ED95 is recommended since severe

degradation of one FKM was observed at 150⁰C for compression set.

Additional testing on HNBR with different ACN content and saturation is recommended

to see if HNBR might be used at higher temperatures in some fuels. Further investigation

of the AEMs not tested is also recommended.

It would be interesting to investigate if there are any clear correlations in data between

the different properties. One example would be the relation of volume swell and

compression set.

55

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58

Appendix A: FTIR spectra FTIR spectra for measurements are presented in this appendix. First a discussion on

analysis of unexposed samples is given followed by all spectra. Identification of rubber

was performed by using SS-ISO 4650. The typical wave numbers for the different

rubbers are summarized in Table 13.

Table 13. Typical wave numbers and corresponding functional groups for different rubbers according to SS-ISO 4650.

8 When the rubber is only partially hydrogenated, a band is observed at 970cm-1 due to -CH=CH- (trans)

Rubber Wave number cm-1 Functional group NBR 910

970 990

1460

1590 Aromatic

2240

3400

HNBR8 720

910

1460

1610 Unsaturation 2240

3400

AEM 1150 to 1260

1460

1740

FKM 1000 to 1400

ECO 1100

CR 700

820

1450

1600 Aromatic

59

Discussion on unexposed samples

NBR_1 and NBR_2 looks similar. Characteristic bonds for NBR (according to SS-ISO 4650,

see Appendix A) are observed. At ~1100cm-1 a signal from a C-O bond is seen, this might

be from the ether that is used as softener. NBR_3 show additional signals from other

bonds at around 1260, 1130 and 1040cm-1. These seems to be related to P=O and P=OR

ester, which is consistent with phosphate used as softener. An additional peak is also

seen at 810 cm-1 which could be C-H stretch of aromatics if for example tricresyl

phosphate is used, see Figure 36.

Figure 36. Chemical structure of tricresyl phosphate that might be used as softener in NBR_3. For HNBRs, one can see that there is a difference between the two types. Both HNBR_4

and HNBR_5 have the characteristic bonds of HNBR, see Appendix A. For HNBR_5

additional signals compared to HNBR_4 are observed in the region 1200-800cm-1. The

signal at ~970cm-1 is probably due to the unsaturation of HNBR_5. The other signals in

the region seem to be related to bonds in ester like C-O and C=O. The signal at

~1730cm-1 can for example be related to C=O bonds corresponding to ester groups in

dioctyl sebacate.

Spectra for all types of AEM look the same. Characteristic signals due to C-O (1150-

1260cm-1) and C=O (1730cm-1) bonds are present.

All types of FKM show the characteristic signal around 1000-1400cm-1 for the C-F group,

but one can see that there is a difference between the types.

Spectra for hoses are generally hard to interpret. This might be due to that analysis has

not been performed on cross sections for hoses, therefore dirt, fabric from

reinforcement and even material from the adjacent layers can be present.

The inside of hose_14 shows a signal at ~1200cm-1 which agrees well with the

characteristic C-F signal in the region 1000-1400cm-1 present in FKM. The remaining

layers have the characteristic signal for C-O-C at ~1100cm-1 present in ECO. This

indicates that hose_14 has an inner layer of FKM, and intermediate layer of ECO and an

outer layer of ECO.

Hose_15 is harder to interpret. The outside and outside towards reinforcement seems

to be the same. According to the manufacturer, it should be CPE. Since no reference

spectra could be found, this cannot be confirmed. The signal at ~660 cm-1 might

http://upload.wikimedia.org/wikipedia/commons/5/57/Tri-o-cresyl_phosphate.svg

60

however be related to C-Cl stretch which is consistent with CPE. Both the inside and

inside towards the reinforcement have the characteristic signal for –CN bonds at

~2240cm-1 which can be related to HNBR. The signal for –CN is stronger for the inside.

Since it was visually observed that the inside and inside towards reinforcement looked

different, it is probable more HNBR in the inside than inside towards reinforcement.

There is also a difference in the region 1100-650cm-1 indicating that the material of the

inside is not the same as the inside towards reinforcement.

Spectra for hose_16 indicate that the same material is used for both the inner and outer

layer since all spectra look the same. The signal for –CN at ~2240cm-1 indicates that NBR

is used in both the inner and outer layer. No signal for C-Cl bond consistent with CR is

seen, see Figure 43. It seems like the manufacturer have not used the material written

on the hose outer surface. But it could also be that the C-Cl peak is not seen due to all

noise present in the region.

61

Unexposed samples

Figure 37. Unexposed sample of NBR. From top down: NBR_1, NBR_2 and NBR_3.

Figure 38. Unexposed sample of HNBR. From top down: HNBR_4 and HNBR_5.

Emmy_ref#1_1Emmy_ref#2_1Emmy_ref#3_ny_1

NameOexp NBR, artnr. 6370001oexp NBR, artnr 6370084oexp NBR, artnr 637003

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

87

7273747576777879808182838485

%T

85

70

72

74

76

78

80

82

84

%T

85

70

72

74

76

78

80

82

84

%T

Unexposed #1 NBR

Unexposed #2 NBR

Unexposed #3 NBR

Emmy_ref#4_1Emmy_ref#5_1

Nameoexp HNBR, artnr 6370087 oexp HNBR, artnr 6370098

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

93

83

84

85

86

87

88

89

90

91

92

%T

89

8181

82

83

84

85

86

87

88

%T

Unexposed #4 HNBR

Unexposed #5 HNBR

1691,5cm-190,238%T

1730,2cm-181,043%T

1688,7cm-186,67%T

1160,4

62

Figure 39. Unexposed sample of AEM. From top down: AEM_6, AEM_7, AEM_8 and AEM_9.

Figure 40. Unexposed sample of FMK. From top down: FKM_10, FKM_11, FKM_12 and FKM_13.

Emmy_ref#6_1Emmy_ref#7_1Emmy_ref#8_1Emmy_ref#9_1

Nameoexp AEM, artnr 6370005oexp AEM, artnr 6570004oexp AEM, artnr 6540060oexp AEM, artnr 6550061

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

83

6162646668707274767880

%T

83

5960646668707274767882

%T

92

7172747678808284868890

%T

91

69727476788082848688

%T

Unexposed #6 AEM

Unexposed #7 AEM

Unexposed #8 AEM

Unexposed #9 AEM

Emmy_ref#10_diamant_1Emmy_ref#11_1Emmy_ref#12_1Emmy_ref#13_1

NameOexp FKM, artnr 6770025. Grönt gummi, diamantkristall

oexp FKM, artnr. 6775035oexp FKM, artnr 6780022oexp FKM, artnr. 6770077

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

101

3140

50

60

70

80

90

%T

93

495560657075808590

%T

94

63666872747880848690

%T

98

71727678808486889294

%T

Unexposed #10 FKM

Unexposed #11 FKM

Unexposed #12 FKM

Unexposed #13 FKM

63

Figure 41. Unexposed hose_14 . From top down: hose_14 inside towards reinforcement, hose_14 inside, hose_14 outside towards reinforcement and hose_14 outside.


Emmy_ref#14_inin_1Emmy_ref#14_inut_1Emmy_ref#14_utin_1Emmy_ref#14_utut_1

Nameoexp slang FPM/ECO/AR/ECO, innerskikt som angränsar mot färstärkning.

oexp slang FPM/ECO/AR/ECO, innerskikt som angränsar utåt

oexp slang FPM/ECO/AR/ECO, utsida som angränsar mot färstärkning.

Description oexp slang FPM/ECO/AR/ECO, utsida som angränsar utåt

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

87

68707274767880828486

%T

98

77

808284868890929496

%T

95

83848586878890919293

%T

92

757678808284868890

%T

#14, inside towards reinforcement

#14 hose, inside

#14 hose, outside towards reinforcement

#14 hose, outside


Nameoexp slang HNBR/CPE, artnr 1949264. Insida som angränsar in mot förstärkning

oexp slang HNBR/CPE, artnr 1949264. Insida som angränsar utåt

oexp slang HNBR/CPE, artnr 1949264. Utsida som angränsar mot förstärkning

oexp slang HNBR/CPE, artnr 1949264.Utsidasom angränsar utåt

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

93

858586878889909192

%T

90

818283848586878889

%T

92

858586

87

88

89

90

91

%T

96

88

89909192939495

%T


#15 hose, inside


#15 hose, outside

64



Nameoexp slang NBR/CR, artnr 1444035, insida som angränsar mot förstärkning

oexp slang NBR/CR, artnr 1444035, insida som angränsar utåt

oexp slang NBR/CR, artnr 1444035, utsida som angränsar mot förstärkning

oexp slang NBR/CR, artnr 1444035, utsida som angränsar utåt

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

93,1

87,688,088,589,089,590,090,591,091,592,092,5

%T

93,9

88,489,089,590,090,591,091,592,092,593,0

%T

95,2

88,689,089,590,591,091,592,093,093,594,0

%T

93,8

88,989,590,090,591,091,592,092,593,0

%T


#16 hose, inside


#16 hose, outside

65

After exposure in B100

Figure 44. B100 exposed sample of NBR_1 for 168h at 115°C. From top down: B100, unexposed NBR_1 and exposed NBR_1.



NameBiodiesel, RME. Artnr. 1546061-31Oexp NBR, artnr. 6370001B100 (RME) exponerad NBR, artnr 6370001, 168h, 115gr

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660

65

70

75

80

85

90

95

%T

87

7273747576777879808182838485

%T

89

7879808182838485868788

%T

B100

Unexposed #1 NBR

Exposed #1 NBR



Description


4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660

65

70

75

80

85

90

95

%T

85

70

72

74

76

78

80

82

84

%T

91

83

84

85

86

87

88

89

90

91

%T

B100

Unexposed #2 NBR

Exposed #2 NBR

1102cm-179,535%T

1088cm-190,016%T

66


Figure 47. B100 exposed sample of HNBR for 168h at 115°C. From top down B100, unexposed HNBR_4 and exposed HNBR_4.

Emmy_B100_diamant_1Emmy_ref#3_ny_1Emmy_B168h115gr#3_1


Description


4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660

65

70

75

80

85

90

95

%T

85

70

72

74

76

78

80

82

84

%T

87

757677787980818283848586

%T

B100

Unexposed #3 NBR

Exposed #3 NBR

1259,5cm-181,83%T

1129,6cm-181,295%T

1041,1cm-178,425%T

811,7cm-182,74%T


NameBiodiesel, RME. Artnr. 1546061-31oexp HNBR, artnr 6370087 B100 (RME) exponerad HNBR, artnr 670087, 168h, 115gr

Description

B100 exposed #4 HNBR, 168h, 115C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660

65

70

75

80

85

90

95

%T

93

8384

85

86

87

88

89

90

91

92

%T

95

8788

89

90

91

92

93

94

95

%T

B100

Unexposed #4 HNBR

Exposed #4 HNBR

67

Figure 48. B100 exposed sample of HNBR_5 for 168h at 115°C. From top down B100, unexposed HNBR_5 and exposed HNBR_5.

Figure 49. B100 exposed sample of hose_15 for 168h at 115°C. From top down: B100, unexposed hose_15 inside towards reinforcement, exposed hose_15 inside towards reinforcement, unexposed hose_15 inside and exposed hose_15 inside.


NameBiodiesel, RME. Artnr. 1546061-31oexp HNBR, artnr 6370098B100 (RME) exponerad HNBR, artnr 6370098, 168h, 115gr

Description

B100 exposed #5 HNBR, 168h, 115C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660

65

70

75

80

85

90

95

%T

89

818182

83

84

85

86

87

88

%T

94

86

87

88

89

90

91

92

93

%T

B100

Unexposed #5 HNBR

Exposed #5 HNBR

Emmy_B100_diamant_1Emmy_ref#15_inin_1Emmy_B168h115gr#15_inin_1Emmy_ref#15_inut_1Emmy_B168h115gr#15_inut_1

NameBiodiesel, RME. Artnr. 1546061-31oexp slang HNBR/CPE, artnr 1949264. Insida som angränsar in mot förstärkning

B100 (RME) exponerad slang HNBR/CPE, artnr. 1949264, insida som angränsar mot förstärkning


B100 (RME) exponerad slang HNBR/CPE, artnr. 1949264, insida som angränsar utåt

Description

B100 exposed #15 hose, inner layer, 168h, 115C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660657075808590

%T

93

8586878889909192

%T

93

86878889909192

%T

90

8182838485868788

%T

87

818283848586

%T

B100

Unexposed #15 hose inside towards reinforcement

Exposed #15 hose inside towards reinforcement

Unexposed #15 hose inside

Exposed #15 hose inside

1109,8cm-190,12%T

68

Figure 50. B100 exposed sample of hose_15 for 168h at 115°C. From top down: B100, unexposed hose_15 outside towards reinforcement, exposed hose_15 outside towards reinforcement, unexposed hose_15 outside and exposed hose_15 outside.

Figure 51. B100 exposed sample of hose_16 for 168h at 115°C. From top down: B100, unexposed hose_16 inside towards reinforcement, exposed hose_16 inside towards reinforcement, unexposed hose_16 inside, exposed hose_16 inside.

Emmy_B100_diamant_1Emmy_ref#15_utin_1Emmy_B168h115gr#15_utin_1Emmy_ref#15_utut_1Emmy_B168h115gr#15_utut_1

NameBiodiesel, RME. Artnr. 1546061-31oexp slang HNBR/CPE, artnr 1949264. Utsida som angränsar mot förstärkning

B100 (RME) exponerad slang HNBR/CPE, artnr. 1949264, utsida som angränsar mot förstärkning


B100 (RME) exponerad slang HNBR/CPE, artnr. 1949264, utsida som angränsar utåt

Description

B100 exposed #15 hose, outer layer, 168h, 115C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660657075808590

%T

92

85

868788899091

%T

95

8788899091929394

%T

96

88899091929394

%T

90

83

848586878889

%T

B100

Unexposed #15 hose outside towards reinforcement

Exposed #15 hose outside towards reinforcement

Unexposed #15 hose outside

Exposed #15 hose outside

1109,8cm-186,708%T

1074cm-188,887%T

1109,8cm-188,286%T

1068,4cm-188,923%T

Emmy_B100_diamant_1Emmy_ref#16_inin_1Emmy_B168h115gr#16_inin_1Emmy_ref#16_inut_1Emmy_B168h115gr#16_inut_1

NameBiodiesel, RME. Artnr. 1546061-31oexp slang NBR/CR, artnr 1444035, insida som angränsar mot förstärkning

B100 (RME) exponerad slang NBR/CR, artnr.1444035, insida som angränsar mot förstärkning


B100 (RME) exponerad slang NBR/CR, artnr.1444035, insida som angränsar utåt

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660657075808590

%T

93

888889

90

91

92

%T

93,3

88,389,089,590,090,591,592,092,5

%T

94

8889

90

91

92

93

%T

94

8889

90

91

92

93

%T

B100





1579,3cm-191,68%T

1513cm-191,978%T

1259cm-191,291%T

1595,9cm-192,89%T

1518,6cm-192,92%T

69

Figure 52. B100 exposed sample of hose_16 for 168h at 115°C. From top down: B100, unexposed hose_16 outside towards reinforcement, exposed hose_16 outside towards reinforcement, unexposed hose_16 outside and exposed hose_16 outside.

Emmy_B100_diamant_1Emmy_ref#16_utin_1Emmy_B168h115gr#16_utin_1Emmy_ref#16_utut_1Emmy_B168h115gr#16_utut_1

NameBiodiesel, RME. Artnr. 1546061-31oexp slang NBR/CR, artnr 1444035, utsida som angränsar mot förstärkning

B100 (RME) exponerad slang NBR/CR, artnr.1444035, utsida som angränsar mot förstärkning


B100 (RME) exponerad slang NBR/CR, artnr.1444035, utsida som angränsar utåt

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

101

5660657075808590

%T

95

89899091929394

%T

94

898990

91

92

93

%T

93,8

88,989,590,090,591,092,092,593,0

%T

94

888990919293

%T

B100





1515,8cm-193,51%T

1551,7cm-193,94

1264,5cm-193,424%T

1261,7cm-192,389%T

70

After exposure in diesel with 7% RME

Figure 53. Diesel with 7% RME exposed sample of NBR_1 for 1008h at 105°C. From top down: diesel with 7% RME, unexposed NBR_1 and exposed NBR_1.


Emmy_Diesel7%RME_diamant_1Emmy_ref#1_1Emmy_D1000h105C#1_1

NameDiesel med 7% RME, artnr. 1546061-35Oexp NBR, artnr. 6370001Dieselexponerad NBR, artnr. 6370001, 1000h, 105C

Description

Diesel with 7% RME exposed #1 NBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

59

65

70

75

80

85

90

95

%T

87

7273747576777879808182838485

%T

91

808081828384858687888990

%T

Diesel with 7% RME

Unexposed #1 NBR

Exposed #1 NBR

1096,4cm-182,134%T

1104,7cm-188,333%T

71


Figure 56. Diesel with 7% RME exposed sample of HNBR_5 for 1008h at 105°C. From top down: diesel with 7% RME, unexposed HNBR_5 and exposed HNBR_5.

Emmy_Diesel7%RME_diamant_1Emmy_ref#3_ny_1Emmy_D1000h105C#3_1

NameDiesel med 7% RME, artnr. 1546061-35oexp NBR, artnr 637003Dieselexponerad NBR, artnr 6370003, 1000h,105C

Description

Diesel with 7% RME exposed #3 NBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

59

65

70

75

80

85

90

95

%T

85

70

72

74

76

78

80

82

84

%T

90

7980

81

82

83

84

85

86

87

8889

%T

Diesel with 7% RME

Unexposed #3 NBR

Exposed #3 NBR

1270,5cm-181,913%T

112481,363%T

1041,1cm-178,425%T

800,64cm-183,002%T


NameDiesel med 7% RME, artnr. 1546061-35oexp HNBR, artnr 6370098Dieselexponerad HNBR, artnr 6370098, 1000h, 105C

Description

Diesel with 7% RME exposed #5 HNBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

59

65

70

75

80

85

90

95

%T

89

818182

83

84

85

86

87

88

%T

94

86

87

88

89

90

91

92

93

%T

Diesel with 7% RME

Unexposed #5 HNBR

Exposed #5 HNBR

72

Figure 57. Diesel with 7% RME exposed sample of hose_16 for 1008h at 105°C. From top down: diesel with 7% RME, unexposed hose_16 inside towards reinforcement, exposed hose_16 inside towards reinforcement, unexposed hose_16 inside and exposed hose_16 inside.

Figure 58. Diesel with 7% RME exposed sample of hose_16 for 1008h at 105°C. From top down: diesel with 7% RME, unexposed hose_16 outside towards reinforcement, exposed hose_16 outside towards reinforcement, unexposed hose_16 outside and exposed hose_16 outside.

Emmy_Diesel7%RME_diamant_1Emmy_ref#16_inin_1Emmy_D1000h105C#16_inin_1Emmy_ref#16_inut_1Emmy_D1000h105C#16_inut_1

Name99,564 %T91,66 %T93,156 %T92,998 %T93,491 %T

CursorDiesel med 7% RME, artnr. 1546061-35oexp slang NBR/CR, artnr 1444035, insida som angränsar mot förstärkning

Dieselexponerad slang, NBR/CR, artnr. 1444035, 1000h, 105C. Insida som angränsar mot förstärkning


Dieselexponerad slang, NBR/CR, artnr. 1444035, 1000h, 105C. Insida som angränsar utåt

Description

Diesel with 7% RME exposed #16 hose inner layer, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5965707580859095

%T

93

888889

90

91

92

%T

94

888990919293

%T

94

8889

90

91

92

93

%T

95

8990

91

92

93

94

%T

Diesel with 7% RME





1515,8cm-191,922%T

1264,5cm-191,685%T

1515,8cm-192,757%T

1588,99

Emmy_Diesel7%RME_diamant_1Emmy_ref#16_utin_1Emmy_D1000h105C#16_utin_1Emmy_ref#16_utut_1Emmy_D1000h105C#16_utut_1

NameDiesel med 7% RME, artnr. 1546061-35oexp slang NBR/CR, artnr 1444035, utsida som angränsar mot förstärkning

Dieselexponerad slang, NBR/CR, artnr. 1444035, 1000h, 105C. Utsida som angränsar mot förstärkning


Dieselexponerad slang, NBR/CR, artnr. 1444035, 1000h, 105C. Utsida som angränsar utåt

Description

Diesel with 7% RME exposed #16 outer layer, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5965707580859095

%T

95

89899091929394

%T

93,8

88,989,590,090,591,091,592,593,0

%T

93,8

88,989,590,090,591,092,092,593,0

%T

94

88

8990919293

%T

Diesel with 7% RME





1256,2cm-193,295%T

1259cm-192,434%T

73

Figure 59. Diesel with 7% RME exposed sample of AEM_7 for 1008h at 135°C. From top down: Diesel with 7% RME, unexposed AEM_7 and exposed AEM_7.

Figure 60. Diesel with 7% RME exposed sample of FKM_10 for 1008h at 135°C. From top down: Diesel with 7% RME, unexposed FKM_10 and exposed FKM_10.


NameDiesel med 7% RME, artnr. 1546061-35oexp AEM, artnr 6570004Dieselexponerad AEM, artnr. 6570004, 1000h, 135C

Description

Diesel with 7% RME exposed #7 AEM, 1008h, 135C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

59

65

70

75

80

85

90

95

%T

83

59606264666870727476788082

%T

91

767778798081828384858687888990

%T

Diesel with 7% RME

Unexposed #7 AEM

Exposed #7 AEM

Emmy_Diesel7%RME_diamant_1Emmy_ref#10_diamant_1Emmy_D1000h135C#10_diamant_1

NameDiesel med 7% RME, artnr. 1546061-35Oexp FKM, artnr 6770025. Grönt gummi, diamantkristall

Dieselexponerad FKM, artnr 6770025, 1000h, 135C. Grönt gummi, diamantkristall

Description

Diesel with 7% RME exposed #10 FKM, 1008h, 135C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

59

65

70

75

80

85

90

95

%T

101

3135404550556065707580859095

%T

101

3235404550556065707580859095

%T

Diesel with 7% RME

Unexposed #10 FKM

Exposed #10 FKM

74




NameDiesel med 7% RME, artnr. 1546061-35oexp FKM, artnr. 6770077Dieselexponerad FKM, artnr. 6770077, 1000h, 135C

Description

Diesel with 7% RME exposed #13 FKM, 1008h, 135C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

59

65

70

75

80

85

90

95

%T

98

7172747678808284868890929496

%T

100

8384

86

88

90

92

94

96

98

%T

Diesel with 7% RME

Unexposed #13 FKM

Exposed #13 FKM

75

Figure 63. Diesel with 7% RME exposed sample of hose_14 for 1008h at 135°C. From top down: diesel with 7% RME, unexposed hose_14 inside towards reinforcement, exposed hose_14 inside towards reinforcement, unexposed hose_14 inside and exposed hose_14 inside.

Figure 64. Diesel with 7% RME exposed sample of hose_14 for 1008h at 135°C. From top down: diesel with 7% RME, unexposed hose_14 outside towards reinforcement, exposed hose_14 outside towards reinforcement, unexposed hose_14 outside and exposed hose_14 outside.

Emmy_Diesel7%RME_diamant_1Emmy_ref#14_inin_1Emmy_D1000h135C#14_inin_1Emmy_ref#14_inut_1Emmy_D1000h135C#14_inut_1

NameDiesel med 7% RME, artnr. 1546061-35oexp slang FPM/ECO/AR/ECO, innerskikt som angränsar mot färstärkning.

Dieselexponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 135Coexp slang FPM/ECO/AR/ECO, innerskikt som angränsar utåt

Dieselexponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 135C. Insida som angrönsar utåt

Description

Diesel with 7% RME exposed #14 inner layer, 1008h, 135C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5965707580859095

%T

87

6870727476808284

%T

91

75788082848688

%T

98

7780828488909294

%T

98

8082848688909294

%T

Diesel with 7% RME





Emmy_Diesel7%RME_diamant_1Emmy_ref#14_utin_1Emmy_D1000h135C#14_utin_1Emmy_ref#14_utut_1Emmy_D1000h135C#14_utut_1

NameDiesel med 7% RME, artnr. 1546061-35oexp slang FPM/ECO/AR/ECO, utsida som angränsar mot färstärkning.

Dieselexponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 135C. Utsida som angränsar mot förstärkning


Dieselexponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 135C. Utsida som angränsar utåt

Description

Diesel with 7% RME exposed #14 outer layer, 1008h, 135C

4000 6503500 3000 2500 2000 1500 1000cm-1

101

5965707580859095

%T

95

83848688909294

%T

94

84

86

88

90

92

%T

92

7576788082848688

%T

92

78808284868890

%T

Diesel with 7% RME




Unexposed #14 hose outside803,28cm-185,927%T

76

After exposure in ED95

Figure 65. ED95 exposed sample of NBR_1 for 1008h at 70°C. From top down: ED95, unexposed NBR_1 and exposed NBR_1.


Emmy_ED95_diamant_1Emmy_ref#1_1Emmy_E1000h70gr#1_1

NameED95, artnr 1546061-29Oexp NBR, artnr. 6370001ED95-exponerad NBR, artnr6370001, 1000h, 70gr

Description

ED95 exposed #1NBR, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

87

7273747576777879808182838485

%T

89

777879808182838485868788

%T

ED95

Unexposed #1 NBR

Exposed #1 NBR

1099,2cm-182,139%T


NameED95, artnr 1546061-29oexp NBR, artnr 6370084ED95-exponerad NBR, artnr. 6370084, 1000h, 70gr

Description

ED95 exposed #2 NBR, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

85

70

72

74

76

78

80

82

84

%T

88

7475767778798081828384858687

%T

ED95

Unexposed #2 NBR

Exposed #2 NBR

1099,2cm-179,453%T

77


Figure 68. ED95 exposed sample of HNBR_5 for 1008h at 70°C. From top down: ED95, unexposed HNBR_5 and exposed HNBR_5.

Emmy_ED95_diamant_1Emmy_ref#3_ny_1Emmy_E1000h70gr#3_correct_1

NameED95, artnr 1546061-29oexp NBR, artnr 637003ED95-exponerad NBR, artnr 6370003, 1000h, 70gr

Description

ED95 exposed #3NBR, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

85

70

72

74

76

78

80

82

84

%T

86

73747576777879808182838485

%T

ED95

Unexposed #3 NBR

Exposed #3 NBR

1259,5cm-181,83%T

1126,8cm-181,238%T


NameED95, artnr 1546061-29oexp HNBR, artnr 6370098ED95-exponerad HNBR, artnr 6370098, 1000h, 70gr

Description

ED95 exposed #5HNBR, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

89

818182

83

84

85

86

87

88

%T

92

8283

84

85

86

87

88

89

90

91

%T

ED95

Unexposed #5 HNBR

Exposed #5 HNBR

1060,5cm-186,103%T

1027,3cm-186,893%T

78

Figure 69. ED95 exposed sample of AEM_7 for 1008h at 70°C. From top down: ED95, unexposed AEM_7 and exposed AEM_7.

Figure 70. ED95 exposed sample of FKM_10 for 1008h at 70°C. From top down: ED95, unexposed FKM_10 and exposed FKM_10.


NameED95, artnr 1546061-29oexp AEM, artnr 6570004ED95-exponerad AEM, artnr. 6570004, 1000h, 70gr

Description

ED95 exposed #7 AEM, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

83

59606264666870727476788082

%T

90

7576

78

80

82

84

86

88

%T

ED95

Unexposed #7 AEM

Exposed #7 AEM

Emmy_ED95_diamant_1Emmy_ref#10_diamant_1Emmy_E1000h70C#10_diamant_1

NameED95, artnr 1546061-29Oexp FKM, artnr 6770025. Grönt gummi, diamantkristall

ED95 exponerad FKM, artnr 6770025, 1000h, 70C. Grönt gummi, diamantkristall

Description

ED95 exposed #10 FKM, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

101

3135404550556065707580859095

%T

101

34404550556065707580859095

%T

ED95

Unexposed #10 FKM

Exposed #10 FKM

79




NameED95, artnr 1546061-29oexp FKM, artnr. 6775035ED95-exponerad FKM, artnr 6775035, 1000h, 70gr

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

93

49

55

60

65

70

75

80

85

90

%T

100

8182

84

86

88

90

92

94

96

98

%T

ED95

Unexposed #11 FKM

Exposed #11 FKM


NameED95, artnr 1546061-29oexp FKM, artnr. 6770077ED95-exponerad FKM, artnr 6770077, 1000h, 70gr

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

102

3235404550556065707580859095

%T

98

7172747678808284868890929496

%T

98

747678808284868890929496

%T

ED95

Unexposed #13 FKM

Exposed #13 FKM

80

Figure 73. ED95 exposed sample of hose_14 for 1008h at 70°C. From top down: ED95, unexposed hose_14 inside towards reinforcement, exposed hose_14 inside towards reinforcement, unexposed hose_14 inside and exposed hose_14 inside.

Figure 74. ED95 exposed sample of hose_14 for 1008h at 70°C. From top down: ED95, unexposed hose_14 outside towards reinforcement, exposed hose_14 outside towards reinforcement, unexposed hose_14 outside and exposed hose_14 outside.

Emmy_ED95_diamant_1Emmy_ref#14_inin_1Emmy_E1000h70gr#14_inin_1Emmy_ref#14_inut_1Emmy_E1000h70gr#14_inut_1

NameED95, artnr 1546061-29oexp slang FPM/ECO/AR/ECO, innerskikt som angränsar mot färstärkning.

ED95-exponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 70gr. Insida som angränsar mot förstärkning


ED95-exponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 70gr. Insida som angränsar utåt

Description

ED95 exposed #14 hose, inner layer, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

32405060708090

%T

87

6870727476808284

%T

89

6970747678808486

%T

98

7780828488909294

%T

99

8284868890929496

%T

ED95

Unexposed #14 hose, inside towards reinforcement

Exposed #14 hose, inside towards reinforcement

Unexposed #14 hose, inside

Exposed #14 hose, inside

1397cm-193,95%T

1162,3cm-177,813%T

1101,5cm-182,575%T

Emmy_ED95_diamant_1Emmy_ref#14_utin_1Emmy_E1000h70gr#14_utin_1Emmy_ref#14_utut_1Emmy_E1000h70gr#14_utut_1

NameED95, artnr 1546061-29oexp slang FPM/ECO/AR/ECO, utsida som angränsar mot färstärkning.

ED95-exponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 70gr. Utsida som angränsar mot förstärkning


ED95-exponerad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 70gr. Utsida som angränsar utåt

Description

ED95 exposed #14 hose, outer layer, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

32405060708090

%T

95

83848688909294

%T

88

6970747678808286

%T

92

7576788082848688

%T

92

7476788082848688

%T

ED95

Unexposed #14 hose, outside towards reinforcement

Exposed #14 hose, outside towards reinforcement

Unexposed #14 hose,outside

Exposed #14 hose, outside

1098,57cm-11515,24cm-1 823,11cm-11260,20cm-1

1542,45cm-1

1 6 4 5 , 9 3 c m - 1

1316,27cm-12918,10cm-1 1406,44cm-1 732,00cm-1

81

Figure 75. ED95 exposed sample of hose_16 for 1008h at 70°C. From top down: ED95, unexposed hose_16 outside towards reinforcement, exposed hose_16 outside towards reinforcement, unexposed hose_16 outside and exposed hose_16 outside.

Figure 76. ED95 exposed sample of hose_16 for 1008h at 70°C. From top down: ED95, unexposed hose_16 inside towards reinforcement, exposed hose_16 inside towards reinforcement, unexposed hose_16 inside and exposed hose_16 inside.

Emmy_ED95_diamant_1Emmy_ref#16_inin_1Emmy_E1000h70gr#16_inin_1Emmy_ref#16_inut_1Emmy_E1000h70gr#16_inut_1

NameED95, artnr 1546061-29oexp slang NBR/CR, artnr 1444035, insida som angränsar mot förstärkning

ED95-exponerad slang NBR/CR, artnr. 1444035, 1000h, 70gr. Insida som angränsar mot förstärkning


ED95-exponerad slang NBR/CR, artnr. 1444035, 1000h, 70gr. Insida som angränsar utåt

Description

ED95 exposed #16 hose, inner layer, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

102

32405060708090

%T

93

888889

90

91

92

%T

91

868687

88

89

90

%T

94

8889

90

91

92

93

%T

93

8586878889909192

%T

ED95





1736,7cm-192,245%T

1736,7cm-191,358%T 1261,7cm-191,286%T

82

After aging

Figure 77. Aged sample in air of NBR_1 for 1008h at 105°C. From top down: unexposed NBR_1 and exposed NBR_1.


Emmy_ref#1_1Emmy_L1000h105gr#1_1

NameOexp NBR, artnr. 6370001Luftåldrad NBR, artnr6370001, 1000h, 105gr

Description

Aged #1 NBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

87

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

%T

88

7676

77

78

79

80

81

82

83

84

85

86

87

%T

Unexposed #1 NBR

Exposed #1 NBR1558,7cm-185,88%T

1583,6cm-186,256%T


Nameoexp NBR, artnr 6370084Luftåldrad NBR, artnr. 6370084, 1000h, 105gr

Description

Aged #2 NBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

85

7070

72

74

76

78

80

82

84

%T

85

73

74

75

76

77

78

79

80

81

82

83

84

%T

Unexposed #2 NBR

Exposed #2 NBR

83


Figure 80. Aged sample in air of HNBR_4 for 1008h at 105°C. From top down: unexposed HNBR_4 and exposed HNBR_4.

Emmy_ref#3_ny_1Emmy_L1000h105gr#3_1

Nameoexp NBR, artnr 637003Luftåldrad NBR, artnr. 6370003, 1000h, 105gr

Description

Aged #3 NBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

85

70

72

74

76

78

80

82

84

%T

83

69

70

71

72

73

74

75

76

77

78

79

80

81

82

%T

Unexposed #3 NBR

Exposed #3 NBR

1260cm-181,818%T

1251,7

1199,1


Nameoexp HNBR, artnr 6370087 Luftåldrad HNBR, artnr 6370087, 1000h, 105gr

Description

Aged #4 HNBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

93

83

84

85

86

87

88

89

90

91

92

%T

92

8484

85

86

87

88

89

90

91

%T

Unexposed #4 HNBR

Exposed #4 HNBR

84

Figure 81. Aged sample in air of HNBR_5 for 1008h at 105°C. From top down: unexposed HNBR_5 and exposed HNBR_5.

Figure 82. Aged sample in air of hose_15 for 1008h at 105°C. From top down: unexposed hose_15 inside towards reinforcement, exposed hose_15 inside towards reinforcement, unexposed hose_15 inside and exposed hose_15 inside.


Nameoexp HNBR, artnr 6370098Luftåldrad HNBR, artnr. 6370098, 1000h, 105gr

Description

Aged #5 HNBR, 1008h, 105C

4000 6503500 3000 2500 2000 1500 1000cm-1

89

8181

82

83

84

85

86

87

88

%T

89

8181

82

83

84

85

86

87

88

%T

Unexposed #5 HNBR

Exposed #5 HNBR

Emmy_ref#15_inin_1Emmy_L1000h105gr#15_inin_1Emmy_ref#15_inut_1Emmy_L1000h105gr#15_inut_1


Luftåldrad slang HNBR/CPE, artnr 1949264,1000h, 105gr, insida som angränsar mot förstärkning


Description Luftåldrad slang HNBR/CPE, artnr 1949264,1000h, 105gr, insida som angränsar utåt

Description

Aged #15 hose, inner layer, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

93

858586878889909192

%T

95

8788899091929394

%T

90

818283848586878889

%T

86,9

80,581,081,582,082,583,584,084,585,085,586,5

%T





1198,7cm-189,016%T

1176,5cm-188,153%T

85

Figure 83. Aged sample in air of hose_15 for 1008h at 105°C. From top down: unexposed hose_15 outside towards reinforcement, exposed hose_15 outside towards reinforcement, unexposed hose_15 outside and exposed hose_15 outside.

Figure 84. Aged sample in air of hose_16 for 1008h at 105°C. From top down: unexposed hose_16 inside towards reinforcement, exposed hose_16 inside towards reinforcement, unexposed hose_16 inside, exposed hose_16 inside.

Emmy_ref#15_utin_1Emmy_L1000h105gr#15_utin_1Emmy_ref#15_utut_1Emmy_L1000h105gr#15_utut_1

Nameoexp slang HNBR/CPE, artnr 1949264. Utsida som angränsar mot förstärkning

Luftåldrad slang HNBR/CPE, artnr 1949264,1000h, 105gr, utsida som angränsar mot förstärkning


Luftåldrad slang HNBR/CPE, artnr 1949264,1000h, 105gr, utsida som angränsar utåt

Description

Aged #15 hose, outer layer, 1008h, 70C

4000 6503500 3000 2500 2000 1500 1000cm-1

92

858586

87

88

89

90

91%

T

91,9

85,386,086,587,087,588,589,089,590,091,0

%T

96

88

89909192939495

%T

98

87888990919293949596

%T



Unexposed #15 hose, outside


1588,4cm-189,472%T

1577,3cm-193,071%T


Nameoexp slang NBR/CR, artnr 1444035, insida som angränsar mot förstärkning

Luftåldrad slang NBR/CR, artnr 1444035,1000h, 105gr, insida som angränsar mot förstärkning


Luftåldrad slang NBR/CR, artnr 1444035,1000h, 105gr, insida som angränsar utåt

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

93,1

87,688,088,589,089,590,090,591,091,592,092,5

%T

95,7

90,8

91,592,092,593,093,594,094,595,0

%T

93,9

88,489,089,590,090,591,091,592,092,593,0

%T

97

909091

92

93

94

95

96

%T





1046,6cm-191,133%T

1016,2cm-190,812%T

86



Nameoexp slang NBR/CR, artnr 1444035, utsida som angränsar mot förstärkning

Luftåldrad slang NBR/CR, artnr 1444035,1000h, 105gr, utsida som angränsar mot förstärkning


Luftåldrad slang NBR/CR, artnr 1444035,1000h, 105gr, utsida som angränsar utåt

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

95,2

88,689,089,590,591,091,592,093,093,594,0

%T

98,4

96,6

96,897,097,297,497,697,898,098,2

%T

93,8

88,989,590,090,591,091,592,092,593,0

%T

96

868788899091929394

%T





87

Figure 86. Aged sample in air of HNBR_4 for 1008h at 135°C. From top down: unexposed HNBR_4 and aged HNBR_4.

Figure 87. Aged sample in air of HNBR_5 for 1008h at 135°C. From top down: unexposed HNBR_5 and aged HNBR_5.


Nameoexp HNBR, artnr 6370087 Luftåldrad HNBR, artnr. 6370087,1000h, 135gr

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

93

83

84

85

86

87

88

89

90

91

92

%T

92

84

85

86

87

88

89

90

91

92

%T

Unexposed HNBR#4

Aged HNBR#4, 1008h, 135C

Emmy_ref#5_1Emmy_L1000h_135gr#5_1

Nameoexp HNBR, artnr 6370098Luftåldrad HNBR, artnr- 6370098, 1000h, 135gr

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

89

808182838485868788

%T

89

808182838485868788

%T

1728,73cm-1; 80,93%T

2924,76cm-1; 81,50%T

1163,63cm-1; 82,83%T

2854,60cm-1; 83,50%T1458,23cm-1; 84,13%T

721,21cm-1; 86,51%T

1727,78cm-1; 80,28%T2924,23cm-1; 80,36%T

1159,93cm-1; 82,04%T2854,02cm-1; 82,24%T

1457,72cm-1; 83,01%T

722,46cm-1; 85,26%T

Unexposed HNBR_5

Air aged HNBR_5, 1008h, 135C

88

Figure 88. Aged sample in air of AEM_6 for 1008h at 135°C. From top down: unexposed AEM_6 and aged AEM_6.



Nameoexp AEM, artnr 6370005Luftåldrad AEM, artnr. 6570005, 1000h, 135gr

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

83

61

62

64

66

68

70

72

74

76

78

80

82%

T

83

61

62

64

66

68

70

72

74

76

78

80

82

%T

Unexposed AEM#6

Aged AEM#6, 1008h, 135C


Nameoexp AEM, artnr 6570004Luftåldrad AEM, artnr. 6570004, 1000h 135gr

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

83

5960

62

64

66

68

70

72

74

76

78

80

82

%T

84

60

62

64

66

68

70

72

74

76

78

80

82

%T

Unexposed AEM#7

Aged AEM#7, 1008h, 135C

89





Description

4000 6503500 3000 2500 2000 1500 1000cm-1

92

7172

74

76

78

80

82

84

86

88

90

92%

T

98

78

80

82

84

86

88

90

92

94

96

%T

Unexposed AEM#8

Aged AEM#8, 1008h, 135C



Description

4000 6503500 3000 2500 2000 1500 1000cm-1

91

6970

72

74

76

78

80

82

84

86

88

90

%T

91

6970

72

74

76

78

80

82

84

86

88

90

%T

Unexposed AEM#9

Aged AEM#9, 1008h, 135C

90

Figure 92. Aged sample in air of FKM_10 for 1008h at 135°C. From top down: unexposed FKM_10 and aged FKM_10.


Emmy_ref#10_correct_1Emmy_L1000h135gr#10_1

NameOexp FKM, artnr.6770025. Grönt gummi. Ge-kristall

Luftåldrad FKM, artnr. 6770025, 1000h, 135gr. Grönt gummi. Ge-kristall

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

101

79

80

82

84

86

88

90

92

94

96

98

100%

T

101

7980

82

84

86

88

90

92

94

96

98

100

%T

Unexposed FKM#10

Aged FKM#10, 1008h, 135C


Nameoexp FKM, artnr. 6775035Luftåldrad FKM, artnr 6775035, 1000h, 135gr

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

93

49

55

60

65

70

75

80

85

90

%T

93

49

55

60

65

70

75

80

85

90

%T

Unexposed FKM#11

Aged FKM#11, 1008h, 135C

91




Nameoexp FKM, artnr 6780022Luftåldrad FKM, artnr. 6780022, 1000h, 135gr

Description

4000 6503500 3000 2500 2000 1500 1000cm-1

94

6364

66

68

70

72

74

76

78

80

82

84

86

88

90

92

%T

95

64

66

68

70

72

74

76

78

80

82

84

86

88

90

9294

%T

Unexposed FKM#12

Aged FKM#12, 1008h, 135C

92




Nameoexp slang FPM/ECO/AR/ECO, innerskikt som angränsar mot färstärkning.

Luftåldrad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 135gr. Insidaskikt som angränsar till armering, kan finnas spår av AR kvar.


Luftåldrad slang FPM/ECO/AR/ECO, artnr. CKR2138000, 1000h, 135gr. Insida

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

87

68707274767880828486

%T

91

737476788082848688

%T

98

77

808284868890929496

%T

98

808284868890929496

%T


Exposed #14 hose, inside towards reinforcemen



Emmy_ref#15_inin_1Emmy_L1000h135gr#15_inin_correct_1Emmy_ref#15_inut_1Emmy_L1000h135gr#15_inut_1


Luftåldrad slang HNBR/CPE, artnr. 1949264, 1000h, 135gr. Insida som angränsar till förstärkning, kan finnas fiberrester.


Luftåldrad slang HNBR/CPE, artnr. 1949264, 1000h, 135gr.Insida som angränsar ut

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

93

858586878889909192

%T

99,2

97,697,898,098,298,498,698,899,0

%T

90

818283848586878889

%T

85,2

78,679,079,580,581,081,582,083,083,584,0

%T


Exposed #15 hose, inside towards reinforcemen



966,48cm-184,843% T

93




Nameoexp slang FPM/ECO/AR/ECO, utsida som angränsar mot färstärkning.

Luftåldrad slang FPM/ECO/AR/ECO, artnr. CKR213800, 1000h, 135gr. Den del av utsidan som angränsar till armeringen. Kan finnas spår av AR


Luftåldrad slang CKR2138000, FPM/ECO/AR/ECO, 1000h, 135gr. Utsida utåt.

Description


4000 6503500 3000 2500 2000 1500 1000cm-1

95

83848586878890919293

%T

91

73

76788082848688

%T

92

757678808284868890

%T

93

75767880828486889092

%T





803,4cm-188,544%T

94

Appendix B: Color graded tables for properties after fuel exposure and aging in air Table 14. Properties for NBR. Color indicating the classification of property: white = small, green= minor, yellow = moderate, red= severe.

Property Material B168h D168h D504h D1008h E504h E1008h E168h A168h A504h A1008h 115C 115C 105C 105C 70C 70C 115C 115C 105C 105C


NBR_1 -17 -9 -7 -9 -6 -7

+10 +13 +19 NBR_2 -27 -20 -21 -18 -3 -3

+8 +9 +17

NBR_3 -13 -4 -3 -3 -2 -4

+6 +8 +18 Volume change (%)

NBR_1 +29.3 +10.4 +9.5 +10.2 +13.2 +13.5

NBR_2 +69.9 +23.5 +24.1 +24.0 +4.7 +5.0

NBR_3 +20.5 +5.6 +5.7 +5.7 +6.5 +5.4


NBR_1 -6.5 +3.1 -53.1 -64.0 -17.3 -22.5

+12.0 +13.8 +22.7 NBR_2 -45.3 -31.3 -85.0 -27.7 -11.0 -19.3

-15.1 -1.9 -5.7

NBR_3 -12.9 -24.8 -12.4 -14.3 -12.5 -15.8

-15.4 -8.6 -7.5 Change in elongation at break (%)

NBR_1 -7.6 -4.2 -57.8 -62.5 -20.2 -30.5

-33.0 -39.8 -66.3 NBR_2 -53.2 -18.2 -78.6 -12.3 -8.6 -17.3

-48.2 -52.2 -79.6

NBR_3 -5.7 -22.5 -16.1 -15.8 -13.6 -17.9

-36.1 -35.0 -68.1 Compression set (%)

NBR_1 +0.9 +25.8 +35.6 +43.1

+46.0 +45.4 +62.4 +71.3 NBR_2 -19.3 10.9 +24.7 +26.7

+33.8 +41.1 +61.6 +72.4

NBR_3 +9.2 +23.1 +32.9 +34.9

+24.0 +29.9 +51.4 +66.1

95

Table 15. Properties for HNBR. Color indicating the classification of property: white = small, green= minor, yellow = moderate, red= severe.

Property Material B D D D D E E E E A A A A A 168h 168h 168h 504h 1008h 504h 1008h 168h 168h 168h 504h 1008h 504h 1008h

115C 115C 150C 105C 105C 70C 70C 115C 150C 115C 105C 105C 135C 135C Hardness change (IRHD units)

HNBR_4 -11

0 0 +1 +3 +5 HNBR_5 -23 -16 -17 -16 -14 -11 -11

0 0 +4 +8 +12

Volume change (%) HNBR_4 +35.8

HNBR_5 +59.8 +29.8 +30.4 +30.9 +31.4 +24.0 +23.4


HNBR_4 -47.7

-0.8 +6.3 +5.8 +6.2 +3.6 HNBR_5 -55.8 -41.3 -42.5 -45.7 -39.0 -32.8 -38.1

+0.3 +2.4 +1.7 +6.8 +11.3


HNBR_4 -21.8

-3.5 -1.9 -2.1 -7.0 -15.1 HNBR_5 -37.0 -23.4 -19.8 -30.9 -26.0 -11.5 -17.3

-3.3 -1.9 -4.7 -22.6 -38.7

Compression set (%) HNBR_4 +2.7

+36.9 +46.5 +42.7 +55.2 +64.4 HNBR_5 -20.3 +12.7 +25.1 +25.1 +26.2

+26.9 +15.8 +44.6 +52.8 +56.5 +76.5 +89.3

96

Table 16. Properties for AEM. Color indicating the classification of property: white = small, green= minor, yellow = moderate, red= severe.

Property Material D168h D504h D1008h E504h E1008h E168h A168h A504h A1008h 115C 135C 135C 70C 70C 150C 165C 135C 135C


AEM_6

-1 -3 -5 AEM_7 -16 -16 -12 -28 -32

+10 +1 +4

AEM_8

at least -10

-8 at least

-10 AEM_9

-2 +1 -2

Volume change (%) AEM_6

AEM_7 +19.8 +19.9 +15.3 +59.1 +62.6

AEM_8

AEM_9


AEM_6

-11.8 -6.4 -13.0 AEM_7 -22.6 -13.9 -14.1 -48.0 -49.4

-17.7 -16.6 -23.8

AEM_8

-22.1 -14.0 -21.2 AEM_9

-14.2 -7.6 -13.4


AEM_6

-13.7 -5.0 -11.6 AEM_7 -10.3 -12.8 -20.9 -22.2 -24.7

-2.6 +1.1 -7.8

AEM_8

+0.2 +2.9 +3.7 AEM_9

+7.4 +3.9 +7.8

Compression set (%) AEM_6

+66.6 +67.6 +78.5 AEM_7 +32.4 +34.4 +55.8

-18.9 +49.9 +49.9 +59.1

AEM_8

+41.0 +49.0 +63.4 AEM_9

+36.0 +46.3 +55.4

97

Table 17. Properties for FKM. Color indicating the classification of property: white = small, green= minor, yellow = moderate, red= severe.

Property Material D168h D504h D1008h E504h E1008h E168h A168h A504h A1008h 115C 135C 135C 70C 70C 150C 165C 135C 135C

Hardness change (IRHD units) FKM_10 -3 -2 -2 -12 -13

0 -1 +1 FKM_11 -3 -3 -3 -5 -5

0 0 0

FKM_12

0 +1 -1 FKM_13 -2 -2 -3 -9 -10

0 +1 0

Volume change (%) FKM_10 +3.3 +3.2 +2.9 +13.1 +13.5

FKM_11 +3.1 +3.1 +3.1 +6.4 +6.6

FKM_12

FKM_13 +4.5 +3.5 +3.9 +11.1 +11.6

Change in tensile strength (%) FKM_10 -24.0 -23.5 -18.6 -45.2 -50.0

+9.0 +4.3 +9.9 FKM_11 -30.6 -41.0 -27.6 -43.8 -43.7

+0.1 +0.7 +1.4

FKM_12

-3.7 +1.2 +0.7 FKM_13 -6.2 -0.6 +6.6 -43.4 -42.3

-2.0 -3.3 -0.7

Change in elongation at break (%) FKM_10 -3.6 -9.4 -6.6 +2.7 -7.2

-4.6 -8.3 -2.3 FKM_11 -9.4 -23.5 -10.5 -12.3 -9.8

-3.8 -4.0 -3.5

FKM_12

-6.1 -1.7 -1.2 FKM_13 +13.3 +12.3 +13.2 +8.5 +13.0

-4.2 -23.2 -3.2

Compression set (%) FKM_10 +17.3 +22.0 +22.9

n/a +23.1 +26.3 +23.2 FKM_11 +30.7 +34.4 +37.8

+39.6 +43.8 +35.8 +39.2

FKM_12

+38.2 +41.8 +41.3 FKM_13 +34.7 +35.6 +37.1

+29.6 +34.9 +37.5 +40.1

98

Appendix C: Bar charts for hoses

Figure 100. Measured changes in volume, hardness, tensile strength and elongation at break for hose_14. The error bars represents ±1 standard deviation.

0

2

4

6

8

10

12

14

16

18

20

Vo

lum

e c

han

ge (

%)

Volume change hose_14

-25,0 -20,0 -15,0 -10,0

-5,0 ,0

5,0 10,0 15,0 20,0

Har

dn

ess

ch

ange

(IR

HD

un

its)

Hardness change hose_14

Inside of hose Outside of hose

-60,0

-50,0

-40,0

-30,0

-20,0

-10,0

,0

Ch

ange

in t

en

sile

str

en

gth

(%

)

Change in tensile strength hose_14

-50 -45 -40 -35 -30 -25 -20 -15 -10

-5 0

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)

Change in elongation at break hose_14

99


,0

10,0

20,0

30,0

40,0

50,0

60,0

70,0

80,0

90,0

100,0

B168h115C

Vo

lum

e c

han

ge (

%)


at least -26

-30

-20

-10

0

10

20

30

40

50

Har

dn

ess

ch

ange

(IR

HD

un

its)



N/A N/A

-50,0

-40,0

-30,0

-20,0

-10,0

,0

10,0

20,0

Ch

ange

in t

en

sile

str

en

gth

(%

)


N/A N/A

-120

-100

-80

-60

-40

-20

0

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)


100


-5

0

5

10

15

20

25

30

35

40

Vo

lum

e c

han

ge (

%)


at le

ast

-29

-40

-30

-20

-10

0

10

20

30

40

Har

dn

ess

ch

ange

(IR

HD

un

its)



-50

-40

-30

-20

-10

0

10

20

Ch

ange

in t

en

sile

str

en

gth

(%

)


-100 -90 -80 -70 -60 -50 -40 -30 -20 -10

0 10

Ch

ange

in e

lon

gati

on

at

bre

ak (

%)


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