ORIGIN OF POLYMERS

EARTH

4 Billion years

C, H, O, N etc. combined to form PROTEINS

LIFE

NATURAL POLYMERS

WOOD, COTTON, CELLULOSE, STARCH ETC.

CLOTHING

ANIMAL SKIN

NATURAL FIBRES

SYNTHETIC FIBRES

POLYMER CLASSIFICATION

a)NATURAL / SYNTHETIC

b)ORGANIC / INORGANIC

c)THERMOPLASTIC / THERMOSETTING

WHAT ARE POLYMERS?

COMPLEX GIANT MOLECULE- DIFFERENT FROM LOW MOL. WT. COMPOUNDS

Eg.1) Nacl - MOL.WT. 58.5

Eg. 2) BUTADINE- MOL.WT. 54

POLY BUTADIENE (* 4000 units)

- MOL. WT. 2,00, 000

1)BIFUNCTIONALITY RESULTS IN LINEAR POLYMERS

2) POLY FUNCTIONALITY RESULTS IN X-LINKED OR BRANCHED POLYMERS

POLYMERIZATION MECHANISMS

a) FREE RADICAL b) IONIC

FREE RADICAL INITIATORS

a) AZO COMPOUNDS

b) PEROXIDES

c) HYDROPEROXIDES

d) PERACIDS

IONIC POLYMERIZATION

a) CATIONIC b) ANIONIC

CATIONIC POLYMERIZATION CATALYST

BF3/HOH (F3BOH)- H+

ANIONIC POLYMERIZATION CATALYST

Eg. BUTYL LITHIUM

LIVING POLYMERIZATION

APPLICATION- MANUFACTURE OF BLOCK COPOLYMERS

COORDINATION POLYMERIZATION

Eg. ORGANOMETALIC COMPOUND/DIENES

RCH2Mt+BUTADIENE

CATALYST- ZIEGLER NATTA- TRIALKYL ALUMINIUM & TiCl3

STEP POLYMERIZATION

Eg.1) POLYHYDRIC ALCOHOL+ADIPIC ACID- RESULTS IN POLYESTER

2) POLYHYDRIC ALCOHOLS- RESULTS IN POLY ETHERS

3) DICARBOXYLIC ACID+ DIAMINES- RESULTS IN POLYAMIDE

TYPES OF POLYMERS

a) RUBBERS

b)PLASTIC

c) FIBRES

CHRISTOPHER COLUMBUS- 15th CENTURY OBSERVED – IN SOUTH AMERICA CHILDREN PLAY WITH BALLS MADE OF NATURAL RUBBER

21 st CENTURY- RUBBER IS A MULTIBILLION DOLLAR INDUSTRY

SYNTHETIC RUBBERS

General purpose

Resistance to chemicalsSolventsFireTemperature

Special purpose

Oil resistance Chemical resistanceExtreme temperature service

General purpose

Styrene butadiene rubber (SBR)Poly butadiene rubber (BR)Ethylene propylene rubber (EPM)Ethylene propylene diene rubber (EPDM)Poly isoprene rubber (IR)Iso butylene isoprene Rubber (IIR)

SBR

SBR elastomer is principally manufactured by the emulsion-polymerization process or by the solution-polymerization process. Although the emulsion process is dominant worldwide, SBR producers are moving toward the solution technology because it yields an elastomer of superior properties. In the emulsion processes, a major portion of the SBR elastomer is manufactured via the cold-emulsion polymerization method; globally, cold emulsion accounts for more than 90% of emulsion SBR.

Styrene - Butadiene Rubber (SBR)

SBR is the largest tonnage synthetic rubber being made all over the world. It accounts for about 60% of the synthetic rubber production and more than 30% of all the rubber consumed. It is a copolymer of butadiene and styrene. The most common SBR is having approximately 25% styrene and 75% butadiene with a random distribution of monomers. There are about 500 grades of this rubber including a large proportion of oil-extended forms and masterbatches of SBR with carbon black. SBR exhibits good abrasion resistance and hence its major application is in tyre sector, especially in passenger car tyres. Other important applications include soles and heels for the footwear, floorings, mats and other domestic items, conveyor belting, hose, rollers, cycle tyres, buffers, gaskets and a large number of other industrial components. About 90% of the SBR produced is by emulsion polymerisation and the rest by solution polymerisation. In addition, about 10% of all the SBR produced is marketed in latex form and is used for applications such as carpet backing, paper coating and latex foam. There is also a small but growing quantity used in adhesives such as butadiene styrene vinyl pyridine for making tyre

Styrene Butadiene Rubber (SBR)

CH2=CH–CH=CH2

Styrene (30%)

Styrene butadiene rubber

Butadiene ( 70%)

4 0C40 0C

Hot SBR Cold SBR

-CH=CH2

- CH2-CH=CH-CH2-

n

CH2

CH

Petroleum crackingDehydrogenation of butanes/butenes

CH2=CH–CH=CH2

Butadiene

-CH=CH2

Styrene

Dehydrogenation of ethyl benzene

Ingredient Hot polymer Cold polymer

Butadiene 75 72Styrene 25 28Water 180 180Fatty acid 4.5 4.5KCL electrolyte - 0.3t-dodecyl mercaptan (modifier) 0.28 0.20K2S2O8 (initiator) 0.30 -P-methane hydroperoxide - 0.063FeSO4. H2O (activator) - 0.010EDTA - 0.05Sodium formaldehyde sulphoxylate- 0.05

Temperature 42 4Conversion 72 60Short stop hydroquinone N-N, dimethyl

dithio carbanmate

Different Grades of SBR

NumberType

SBR – 1000 Hot polymersSBR – 1100 Hot balck filled SBR (14% oil)

SBR – 1500 Cold polymerSBR – 1600 Cold black filled SBR (14% oil)SBR – 1700 Cold oil master batchSBR – 1800 Cold black filled SBR (>14% oil)SBR – 1900 Miscellaneous dry polymer

SBR – 2000 Lattices hotSBR – 2100 lattices cold

Properties of SBR

SBR is inferior to NR

ProcessingTensile strengthTear strengthTackHeat build-up

SBR is superior to NR

PermeabilityAgeingResistant to heat and wearReinforcement by carbon blackLow viscosityPremastication not requiredLess scorch

Compounding and Processing

SBR is slower curing than NR Requires lower less sulphur & more accelerator Scorch problems are less with SBR

ZnO 3 – 4Diethylene glycol 1.5 – 2(Triethanol amine)Stearic acid 1.5 – 2Process oil 5 – 7Filler 20 – 30Antioxidant 1 - 3Accelertor (sulphenamide) 1.5 – 2Sulphur 1.5 - 2

Applications

Passenger car tyresWiresCablesShoe solesExtruded goodsSBR lattices are used in carpet back coatings

Polybutadiene Rubber (BR)

Polybutadiene can be produced by both emulsion and solution polymerisation. Emulsion polymers are of random nature in stereospecificity. Solution polymers can be manufactured into stereospecifically tailor-made forms. It is achieved with the use of different catalysts such as anionic or ziegleratta type. BR has excellent resilience, abrasion resistance, and low temperature flexibility. BR can have higher filler loading and oil extension without property deterioration. Tear strength and resistance to cut growth are relatively poor for BR and hence is used as a blend with other rubbers. About 90% of BR is used in tyres, blended in various proportions with SBR, NR etc. Other application of BR is as an additive in rigid plastics such as polystyrene for impact modification. Other engineering applications such as V-belts, conveyor belting, solid rubber tyres, antivibration mounting roller covering and flexible heavy duty suction and discharge hoses.

CH2=CH–CH=CH2

Butadiene Rubber

n

Butadiene

-CH2-CH=CH-CH2- n

cis-Poly butadiene

Production Solution/emulsion polymerisationEmulsion BR Low mol.wt and shows cold flowSolution BR High mol.wt and difficult to process

Properties of BR

Very good low temperature propertiesLow heat build-upHigh resilienceBetter flex resistanceGood heat stability

Very high air permeabilityPoor tackPoor road gripPoor tear and tensile strength

Processing

Highly resistant to break down and poor mill bandingRough extrusion appearanceTight nip and low mixing temperature preferredUsed along with NR or SBR

Applications

Truck tyre treadsModifier to plastics

Ethylene Propylene Rubber (EPM / EPDM)

Raw materialsEthylenePropyleneCatalysts

Amount of unsaturation in EPDM is 0.6 to 1,0 %

Properties

Resistance to ozone and weatheringResistance to heat ageing and compression setChemical resistanceLow temperature flexibilityLow polymer specific gravityGood physical properties in highly filled stocksFast mixing, moulding and extrusion characteristicsExcellent electrical properties

Applications

Electrical insulation and jacketingAutomotive sealsAutomobile hoses

Polyisoprene Rubber (IR)

This rubber can be considered as a synthetic replica of natural rubber (NR). Special catalysts that could produce Cis-1, 4-Polyisoprene, the chemical analogue of NR was invented by the middle of the 20th century. Synthetic material is purer than NR, as the latter contains protein, wood resins and other non-rubber constituents. Applications include tyres, extruded gaskets, sheeting, footwear, sponge rubber and springs. Gutta-percha, the trans isomer of polyisoprene can also be made synthetically. It finds application as insulating material in deep sea cables and gall ball covers.

Poly Isoprene Rubber (IR)

Solution polymerisation techniques

Stereo isomeric purityMolecular weight and molecular weight distributionPresence of functional groups attached to the polymer chainImpurities

Processing

Little tendency of storage hardeningInitial banding is rapidAvoid over masticationCare for good dispersion

ApplicationsAreas where NR is usedProduction of Chlorinated and isomerised rubbersPharmaceutical industry

CH2=C–CH=CH2

CH3

1soprene(C5H8)

- CH2-C=CH- CH2 -

CH3

n

Cis-1,4-poly 1soprene

C C

CH2CH2

CH3 H

C C

CH2CH2

CH3 H

C C

CH2CH2

CH3 H

C C

CH2CH2

CH3 H

C C

CH3H

CH2CH2

C

CH2

CH3

C

CH2

H

C C

CH2CH2

CH3 H

C C

CH2CH2

CH3 H

C C

CH2CH2

CH3 H

C C

CH2CH2

CH3 H

C C

CH3H

CH2CH2

C

CH2

CH3

C

CH2

H

Cis-1,4 Polyisoprene (Natural Rubber)

trans-1,4 Polyisoprene (Guttapurcha)

Butyl Rubber (IIR)

Butyl Rubber is a solution copolymer of isobutylene with a small proportion (from 1 to 4%) of isoprene. Polyisobutylene by itself is fully saturated, and the isoprene is included to provide sufficient double bonds to allow vulcanisation with sulphur. Its outstanding property is the very low permeability to air and other gases. Low resilience, very good resistance to sunlight, ozone and aging, and relatively good resistance to high temperature are the other specialities. Butyl tends to be incompatible with other rubbers, but this difficulty can be overcome by modifying the polymer with chlorine and bromine to give chlorobutyl and bromobutyl rubbers.

The main application for all forms of butyl rubber is to make inner tubes for tyres, and more recently is being used as linings for tubeless industries. Its high heat resistance has lead to its utilization for applications such as steam hose and the curing bags used in tyre vulcanisation. Sunlight and weather resistance of butyl is exploited in roofing membranes and reservoir sheeting. Its chemical resistance is made use of in anticorrosion linings.

Iso Butylene Isoprene Rubber (IIR)

Co-polymerisation of isobutylene with isoprene at very low temperature ( - 65oC)

Properties

Low rates of gas permeabilityThermal stabilityOzone and weathering resistanceVibration damping and higher coefficients of frictionChemical and moisture resistance

Butyl rubbers are characterized by

Mooney viscosity (ML=100oC(1+8) -- 41 to 49 Degree of unsaturation---- 0.7 to 2.2 mole %Type of antioxidant---- non staining antioxidant

Production by Exxon Butyl (USA)Polysar Butyl (Canada)

Processing

Mastication – low level of unsaturation, difficult to degrade, use of plasticizer is recommended (DCP)Mixing - Low mooney grade, cold tight mill, high mooney higher

temperature is preferredExtrusion --Extruded surfaces has smooth surfaces and finish, filler

is added to reduce the nerve, Extrusion temperature 200-270 oC

Building - good green strength, good for building purposesVulcanization: Free of scorch, reversion ec, accelerated sulphur

vulcanization, crosslnking with dioxime and related nitroso compound and polymethylol-phenol resin

Softeners: Paraffinic oils

Sl No.

Product Manufacturer Capacity

1 SBR Synthetics & Chemicals Ltd.

41,000

Apar Ltd. 5,000

2 BR IPCL 50,000

3 NBR Apar Ltd. 8,000

4 EPDM Herdillia Ltd. 10,000

5 VP Latex

Apcotex 1,000 (D.WT)

ENPRO 1,000 (D.WT)

Synthetic Rubber Production in India

USA EUROPE FAR EAST

Dexco polymers

Dow Europe Asahi Kasei,Japan

Lion copolymers

Dynasol, Elastomers, spain

Kabushiki,Japan

Dupont performance elastomers

Exxon chemical, Europe

JSR Corporation, Japan

Exon mobil Michelin, France

Kumho, Korea

Firestone polymers

Polimeri, Europa

LG Chem, Korea

Goodyear Tyre and Rubber Co.

Petrochina, China

Reliance Industries, India

Nitrile Rubber (NBR)

CH2=CH–CH=CH2

Butadiene ( 70%)

CH2=CH CN

Acrylonitrile

-CH2-CH=CH-CH2 -CH2=CH- CN

n

+

Acrylonitrile butadiene rubber

Copolymer of butadiene and acrylonitrile by emulsion process

Properties

Good resistance to a wide variety of non-polar Oils, fats and solvents

Acrylonitrile content (20-50%)

Low ---25%Medium —35-50%High ---35-50

Hot NBR----- 30 oC (Trans 52 %) Cold NBR--- 7 oC (higher)