Preparation and Properties of Titanium Nano Modified Epoxy-siloxane Self-strat­ifying Anticorrosion Coating

Zhi Zeng* 1 , Yi-xiang Cai2, Huan-wen Xie2

, Lei wang2

n Zhuzhou Times New material technology Co. Ltd. , Haitian Road 1 ,Zhuzlwu, Hunan Province ,China, 412007 2 >Guanzhou Research Institute for Nonferrous Metal Changxing Road 363 ,Guangzhou,Guangdong Province ,China, 150000

Taking the titanium nanometer modified polymer as main raw material, the titanium nanometer modified self-stratifying anticorrosion coating

was developed. The titanium nanometer modified polymer was prepared by planetary high energy ball milling with the epoxy-siloxane copolymer

and titanium powder. The titanium nanometer modified self-stratifying anticorrosion coating was obtained by mixing the titanium nanometer

modified polymer with general epoxy and other additives. The average particle size of titanium nanometer modified by polymer was studied

through centrifugal particle size analyzer and its morphology was observed by SEM. The distribution of titanium nanometer modified polymer in

coating was investigated by EMPA. The results indicated that organic modified titanium nano powder had been prepared by ball milling. For the

difference of surface energy.a functionally gradient coating grew during the process construction, fully integrated the good adhesion and corro­

sion resistance of epoxy primer and non-stick performance, sterilization bactericidal inhibition, antifouling performance of titanium nanometer

modified epoxy-siloxane copolymer finish. This technology can decrease the use of titanium, simplify the coating construction and reduce the

costs.

Keywords: Titanium powder .self-strati/ ying ,anticorrosion coating

1. Introduction

Titanium is an ideal coating industry metal filler for its light weight, excellent corrosion-resistant, non­toxic, high strength and so on,attracts corrosion work­ers attention over a longer period of time1. 2>. Titanium­polymer coating constitutes by resin, curing agent, tita­nium powder, additives, small amount of solvent and etc3

'1>. But the experimental results proved that the or­

dinary industrial titanium powder directly added into the organic resin coating composition, did not show a clear advantage by compared to other inorganic fill­ers5>. Strong mechanical milling of titanium powder with resin, additives, solvents and other raw materials can prepared the titanium-polymer coatings6>. Mechani­cal-chemical reaction can further refinement the parti­cle size of titanium powder during the preparation, and can promote the interaction between the titanium pow­der filler with res inn. However, the high cost of titani­um metal powder has affected its application in general industry, particularly in the field of civil industry appli­cation. If the titanium metal and organic polymer mate­rials combine to form the metal-polymer, then high­lighted the corrosion-resistant properties of titanium by the form of self-layered, to promote the use of metal structures anti corrosion of industrial areas. This can greatly reduce the manufacturing cost, and improving the economic benefits. This is the purpose of this re­search project.

This paper aims at the modification technology of nano-materials, explored the reaction of the low surface epoxy-siloxane resin with titanium powder to prepare the nano-titanium organic hybrid polymer, mixed it with ordinary epoxy resin to develop series special lay­ered anticorrosion coating by the self-stratifying phe­nomenon of the mixture of difference surface energy

materials. This work can open up a new way for the ti­tanium-polymer anti-corrosion coatings industry.

2. Experimental

2. 1 Materials 100 Mesh titanium powder ( Shengchang Industry

& Trade Co. , Ltd. Baoji); HG--43 epoxy-siloxane resin (Chenguang Research Institute of Chemical Industry); El2 epoxy resin (Guangzhou Dongfeng Chemical In­dustrial Co. , Ltd. ) ; BDll epoxy resin curing agent at room temperature ( Xiangfan Lianji adhesives Co. ) ; BYK-P 104S controlled flocculating wetting and dis­persing additive ( BYK (Tangling) Co. , Ltd. ) ; T-75 coupling agent ( Qingxin Ganerchem Chemical Tech­nology Co. Ltd. ) ; 691 defoamcr agent (Guangzhou Shuangjian Trading Co. , Ltd. ) ; GSK-512 wetting and leveling agent ( Grosskin Fine Chemistry Co. , Ltd. ) ; CYH-277 reactive epoxy toughening agent (Wuhan Senmao Fine Chemical Co. , Ltd. ) . All the other chem­ical reagents were purchased from Beijing Chemical Re­agent and purified by conventional methods.

2. 2 Measurements Scanning electron microscopy ( SEM ) was per­

formed on a JEOL JSM-5910 scanning electron micro­scope at a voltage of 20 kV. It was also performed on a JEOL JSM-6330F scanning electron microscope at a voltage of 15 kV. Samples were sputter-coated with a 10 nm-thick layer of gold prior to imaging.

Electron probe micro-analyzer ( EPMA) was per­

formed on a JEOL JXA-8100 electron probe micro-ana­lyzer at a voltage of 6 kV. Samples were sputter-coated with a 10 nm-thick layer of carbon prior to imaging.

Particle size was performed on a Shimadzu Corpo­ration SA-CP3 centrifugal particle size analyzer.

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12. Marine Applications • 2261 •

Pencil hardness was eva luated on cured films ac­cording to the standard tes t method ASTMD3363-1974. Impact strength was evaluated on cured films ac­cording to the s tandard test method ASTM Gl4- l 977. Adhesion was evaluated on cured fi lms according to the standard test method ASTMD 3359-1993. F lexibility was evaluated on cured films according to the s tandard tes t method ISO 6860-1984. Water resistance and hot water performance was eva luated on cured films ac­cording to the standard test method ISO 1521-1973. Hea t resis tance was eva luated on cured films according to the standard test method ISO 3248-1998. Acid, a lkali and salt resistance was eva luated on cured fi lms ac­cording to the standard test method I 0 2812-1974.

2. 3 Preparation of Epoxy-siloxane Resin Modified Tita­niwn Powder In the reactor tank of plan tary ball milling CQM-

2SP12, Nanjing anDa Instrument Plant ) was placed HG-43 (400g), acetone (200g) , xylene (50g), BYK-P 104s (lg) , -100 mesh titanium powder ClOOg) and T -75 (lg), and sea led aft er add ing steel ball in propor­tion. Then the mixture will keep grinding at 325 revo­lutions per minute for 5 hours. After natural cooling to room tempera ture , the black mud- like products was ob­tained after filter out the ball s , named HG-43-Ti.

2. 4 Preparation of Self-stratifying Anticorrosion Coat­ing

In the barrel of disperse grinds s tirs machine ( MXD-8400 , Shanghai GSEM Machinery &. Electri c Equipment Co. , Ltd. ) was placed xylene (50g) , isobu­tanol ( 30g) , methyl ethyl ketone ( 50g ) , HG-43-Ti (lOOg) , E-12 (lOOg), CYH-277 (40g), 691(0. 3g) , in proper order. After a ll the cast, the mixture stirred at high-speed for 30 min, and then added into the horizontal close sand mill ( SWM5 , Chongqing Hongda Chemical Machinery &. Appliance Co. , Ltd. ) and grinded to the required degree of finen ss , filtered, adjusted the viscosi­ty, tested and packaging. This is the A components.

In the barrel of disperse grinds s tirs machine ( MXD-8400 , Shanghai GSEM Machinery &. Electric Equipment Co. , Ltd. ) was placed BDll ( 20g), xylene (5g), isobutanol (3g), methyl ethyl ketone (5g) , GSK-512 (lg) in proper order. After all the cast, the mix­ture stirred at high-speed for 30min, and then added in­to the horizontal close sand mill and grinded to the re­quired degree of fineness , fi 1 tered, adjusted the vi scosi­ty, tested and packaging. This is the B components.

2. 5 Preparation of Paint Test Panels

Prepared numbers of 120 X 60 X 0. 5mm cold rolled steel sheet, made the substrate rough by sandpaper, cleaned with acetone, dried for use. Mix A/ B compo­nent of the titanium-polymer coating at an appropriate

ratio, adjusted its viscosity with thinner ( xylene : methyl ethyl ketone : isobutanol = 50 : 50 : 30) for spray (18~30s / Tu-4 cup) or brush (30~50s) . T est

panels were coa ted in a single paint or complex paint. T o prepara tion of composite paint, each paint intervals lh for surface dry. The corrosion resistance tes t and physica l performance tes t will carry on a week latter for completely cured.

3. Results and Discussion

3. I The Surface and Particle Size of HG-43-Ti Powder In order to observe the distribution and di spers ion

of HG-43-Ti powder, indus tria l titanium powder and HG-43-Ti powder samples were tested by SEM, re­spectively, the results shown in Figure 1. Figure 1 shows that, the industria l titanium powder is massive, and its particle size fa ll in the range of 20~ 1 20 µm. After grinding, the HG-43-Ti powder is irregular fl akes , and its particle size fall in range of 200 ~ 500 nm. During the high-energy ball milling process , the granules are refined to the nanometer level, grinded and welded continuously by the mechanical forces. For the increasing of specific surface area, the probabi li ty of combined with the polymer increased. The H G-43-Ti powder in test has been extraction with acetone by soxhlet extraction for 24 hours to avoid the impact of dissociative organic matter. The sample in Figure 1 ( b) is more evenly di stributed, and its surface a ttached with a thin looming layer. It can be concluded that this is caused by the bonding reaction or adsorption of poly­mer to the titanium nano-particles.

Figure 1. SEM micrographs of industrial titanium powder (a)

and HG-43-Ti powder ( b)

Centrifugal sedimenta tion type particle size analy­zer was also used to test the particle size distribution of HG-43-Ti powder, as results shown in Figure 2. As shown, the median diameter is 1.16 µm,1 0. 0 % diame­ter is 0.16 µm, 90. 0% diameter is 9. 38 µm. The spe­cific surface area is 2. 7 48 m2

/ g. The ball milling process is complexly, uncontrollable , with blind area , so large particles of the powder might have a little residu­al; or the combination of the titanium particles with the polymer increased the single particle size , and polymer bonded the particles together increasing the sample size when solvent evaporated to dry. The adhesion phenomenon between powders observed clearly through the SEM ima­ges, shown the reunion caused by the polymer. Therefore,

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• 2262 • Proceedings of the 12'h World Conference on Titanium

the result of the measured data is greater than SEM 25~~~~~~~~~~~~~~~~~~

20

~ 15 ~ c:

~ I O u

4 6

I- HG-43-Ti powder I

8 IO 12 14 Diam(µm)

Figure 2. The particle s ize indexing chart of HG-43-Ti powder

3. 2 The Self-stratifying Phenomenon of Coating After fully cured, the coating surface was black

opaque metallic luster. The fracture plane of the coating was got by fracture it in liquid nitrogen. Stratification

300µm

60 Si

50

40

30

20

IO

100 200 µm Ttsram Ka i

section observed by visual observation shows that : no obvious coating interface section occurred, but the gloss and color of the surface are brighter than th~ bottom

EMPA was also used to observe the plane of the fracture. Photos from the cut surface of the coating lay­er see Figure 3. Epoxy-siloxane resin coating contains silicon and titanium, while epoxy resin coating not. Therefore, by comparing the silicon and titanium con­tent of the cut surface of layer, the di stribution of the epoxy-siloxane resin and the stratifi cation of the coat­ing will acquired by further analysis of the situation.

From the results, the concentration of titanium and si licon element in surface was significantly greater than the back of coating film. This can be interpreted as the possible reaction with Ti and epoxy-siloxane during the milling process, which results the connection of titanium and resin, then the silicon-epoxy enriched on the surface with titanium for its low surface to form the gradient films during the film-forming process. The iron has the same phenomenon during milling process.

100

50

0 0 100 200 µm

Ttsram Ka i

Fe 30

20

IO

100 200 µm Ttsram Kai

Figure 3. Morphology of the titanium- polymer coatings film and element contents in different depth of the film

3. 3 The Physical Properties and Corrosion Resistance of Coating

The configured titanium-polymer coa ting was coa­ted onto the cold roll ed steel sheet treated by sand blasting. The coating thickness was about 200 µm, cured at room temperature in the air, then the perform­ance test executed. The physica l and mechanical prop­erties of the titanium-polymer coating were listed in Table 1, respectively. From the table , the coa ting film has excellent flexibility, adhesion and impact strength.

1lible 1. Physical and mechanical properties of the titanium-polymer coating

Titanium-polymer coating Properti es

Pencil hardness 3 H

Acid resistance 25 'C,5 wt % HCl,400 h, no change

Alkali resistance 25 'C , 5 wt% NaOH,400 h, no change

Salt tolerance 25 'C ,5 wt % aCl, 400 h, no change

Water resistance 25 'C, 72 h, no change

Hot water performance boiling water,30 min, no change

Heat resistance Oven, 150 'C, 72 h, no change

Adhesion ~4 B

Impact st rength ( / cm2) ~500

Flexibility 5 g rade

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12. Marine Applications • 2263 •

Soaking the sample in the corrosive media, film at 5 wt% NaOH,HCl,NaCl solution did not change after 400h immersion, respectively. There appeared no dis­coloration, blistering, wrinkling, loss, rust and so on. Anti-corrosion paint film has good performance of acid, alkali and salt resistance. The fallen iron during milling had no adverse effect on the film.

4. Conclusions

( 1) Nano-titanium-polymer was prepared by the application of high-energy ball milling, and nano-titani­um-polymer anticorrosion coatings were obtained.

(2) Titanium powder was adsorption and coated with epoxy-siloxane, its particle size fallen in the range

of 200 ~ 500nm, and well-proportioned distribution without serious agglomeration.

( 3 ) Anti-corrosion coatings were prepared by mixing the HG-43-Ti powder with other epoxy resin for its excellent dispersibility. A gradient film obtained for its self-stratifying phenomenon of epoxy-siloxane during the construction process.

( 4) Large number of corrosion test showed that the nano-titanium-polymer coatings have excellent cor­rosion resistance ability.

Acknowledgements

Financial support for this project was provided by the Guangdong Provincial Department of Science and Technology (No. : 2007AO10500013).

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plantation on Corrosion Resistance and High Temperature Oxi­dation Resistance of Ti Deposited 316 Stainless Steel. Surface and Coatings Technology, 2002, I0, 158-159.

2) G. Lu, L. Steven. Oxidation of a Polycrystalline Titanium Surface by Oxygen and Water Surface Science. 2000,458,80-90.

3) J. F. Xue, F. J. Xue. CNOOl32108. 0. 4) J. F. Xue,F. J. Xue. CNOOI05672. 7.

5) T. Jesionowski, J. Zurawska, A. Krysztafkiewicz, M. Pokora, D. Waszak, W. Tylus. Applied Surface Science, 2003, 205, 212 -224.

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To whom correspondence should be addressed. Phone: 086-731-22837934. Fax: 086-731-22884 725. E-mail: zengzhi345@yahoo. com. en.

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