Effects of Replacement of Part of the Silica Reinforcement with Hybrid Modified Microcrystalline Cellulose on the Properties of their Rubber Composites

Hybrid modified microcrystalline cellulose (HMCC), with SiO₂ nanoparticles being in-situ loaded on the surface of microcrystalline cellulose (MCC), was obtained through a sol-gel process of tetraethoxysilane (TEOS) by using ammonia as catalyst. HMCC was characterized by thermogravimetric analysis and scanning electron microscopy. The results showed that the spherical nano-SiO₂ particles had been loaded successfully on the surface of the MCC with a loading ratio of approximately 10%. Then the HMCC was used in high vinyl solution-polymerized styrene butadiene rubber (SSBR)/silica compounds to replace part of the silica, and its effects on the physio-mechanical and dynamic mechanical properties of the vulcanizates were investigated. The results showed that the HMCC samples had improved physio-mechanical properties and lower heat build-up than that of MCC ones. Dynamic mechanical analysis (DMA) showed that the tanδ value of the compounds decreased at 60°C while increased obviously at 0°C, which meant that the tires would have improved wet-skid resistance while maintaining low rolling resistance when HMCC was used in tire tread compounds. As observed from scanning electron microscopy (SEM) photos, the sizes of the HMCC were in-situ decreased from 20–90 µm to 0.5–10 µm during the processing of the rubber compounds. Compared with MCC, the interfacial adhesion between HMCC and rubber was also improved greatly.