Utilization of silicon dioxide powder from industrial wastes as novel filler in rubber isolator application

The silicon dioxide powder (SP) was an industrial waste and obtained from the silicon metal industry in Thailand. The effect of SP loading on cure characteristics, mechanical, dynamic and endurance properties in natural rubber were investigated and compared to calcium carbonate (CaCO3) and unfilled natural rubber, respectively. Results revealed that the addition of SP significantly affected the cure characteristics and mechanical properties. An increasing content of SP increased the hardness, modulus, tensile strength and tear strength due to a higher SP-rubber interaction but decreased the elongation at break since higher SP in rubber matrix resulting in lesser mobility of rubber chains. For the curing behavior, the faster cure time was observed since more heat transfer to the compound occurred. The rubber product performance in terms of dynamic and endurance properties of rubber isolator were also determined. It had been found that SP not only improving the damping characteristics but also enhancing the number of cycles until fracture. Moreover, adding the bis-(3-triethoxysilylpropyl)-tetrasulphide (TESPT) showed higher reinforcement efficiency of SP. This can directly react to silanol groups on the SP surface and also reduce hydrogen bonding of SP particles. So, TESPT can reduce accelerator adsorption and SP-SP interaction, leading to better processability. Besides that, TESPT is a sulphur-based rubber silane. It can contribute sulphur atoms from molecule and then form covalent bonds with natural rubber chains which leads to enhance the crosslink density. Influence of tiller type on rubber isolator, the SP imparts greater reinforcement than CaCO3. All obtained results suggested that SP can be fully replaced the commercial CaCO3.