Styrene-butadiene Rubber (SBR) composites were manufactured by colloidal adsorption method with three kinds of reinforcing agents (silica, starch-silica gel hybrid and cellulose-silica gel hybrid) and SBR l502 latex. The crosslink structure of compounds was observed with field-emission scanning electron microscope (FE-SEM). The density, hardness value, tensile strength, storage modulus, dynamic mechanical property, and oil resistance had been characterized. From the results of all tests, starch/cellulose-silica hybrid could make good reinforcement effect due to the interpenetrating network between hybrid and rubber matrix had been formed. The best filler was cellulose-silica hybrid 10 phr, which showed the best reinforcement effect with SBR compound.

스티렌-부타디엔 고무 Latex 1502에 세가지 충전제(실리카, 실리카와 전분 혼성체, 실리카와 셀룰로오스 혼성체)를 콜로이드 흡착법으로 혼합하여 고무복합체를 제조하였다. 주사전자현미경을 통해서 가교 구성을 확인하였으며, 고무복합체의 비중, 경도, 인장강도, 저장탄성률, 동학역적 성능 및 내유성을 조사하였다. 실험의 결과에서 실리카와 전분/셀룰로오스 혼성체가 고무와 상호 침투 네트워크(Interpenetrating network)를 형성하여 좋은 보강 성능을 보였다. 그 중에서도 실리카와 셀룰로오스 10 phr 혼성체가 SBR 복합체에 가장 좋은 보강 효과를 보였다.

Keywords: cellulose, starch, styrene-butadiene rubber, silica, oil resistance

As the surge in the oil price and global warming occurring from carbon dioxide emissions, the application of natural resources in the polymer matrix has attracted enormous interest from both academic and industrial researchers in recent years. The application of renewable resources instead of nonrenewable resources in the polymer matrix not only largely reduces the cost of products, but also is good for our environment. ¹ Among lots of the renewable resources, starch and cellulose are cheapest and most abundant natural resources on the earth, which can be derived from corn, wheat, potato, rice and wood etc.² Therefore, starch and cellulose have been widely investigated for the potential application in various fields, such as coating, adhesives, flocculants, superabsorbent polymers, biodegradable polymers and packing films.³
Recently, the development of starch/cellulose as reinforcing filler in the rubber compounds has received increasing attention. But as common natural polymer, one of the major bottlenecks for starch/cellulose used as reinforcing filler in the rubber compounds is their large particle sizes. Another one of the major bottlenecks is their hydrophilic surface,⁴ which lead to poor interfacial adhesion with the hydrophobic rubber matrix, especially for the non-polar rubber, such as SBR and NR. Therefore, various surface modification methods, such as grafting of poly(butyl-acrylate), esterification with xanthate,⁵ crosslinking with resorcinol-formaldehyde and isocyanate have been reported to enhance the interfacial bonding.⁶
Almost physical crosslinking methods depend on non-covalent bond, such as hydrogen bond, van der waals force and other intermolecular force.⁷ Recently, some researchers use network structure or cyclic structure hydrogel as the physical crosslink agent, which could provide more hydrogen bonds to form the physical crosslinking network. And this method offers a much wider range of properties than conventional crosslinked elastomers because the domains that act as crosslinks are reversible. And interpenetrating polymer network (IPN)⁸ is shown in Figures 1 and 2. It is a polymer comprising two or more networks which are at least partially interlaced on a polymer scale but not covalently bonded to each other. In interpenetrating polymer network, when the physical crosslinking and chemical crosslinking occur simultaneously in a polymer material, it is speculated that the material may have better mechanical properties, such as modulus, hardness and crosslinking density.⁹
In this research, the starch/cellulose had been modified into gel-state, and then mixed with silica to get the gel-hybrid which could institute the interpenetrating network polymer with SBR latex by gel adsorption method, and then get the vulcanizates during the curing processes. Finally, the mechanical properties with various methods were characterized, such as DMA, tensile stress, oil resistance, and others.