Effect of silica type, content, and silanization on the curing, mechanical and energy dissipation properties of poly (epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) elastomers

Abstract

This work aimed to determine the effect of unmodified raw silicas and modified silicas with silane coupling agents on the curing, mechanical, and energy dissipation properties of poly (epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) based elastomers. The modified silicas utilized include Coupsil 6109, Coupsil 8113, and Coupsil VP6411, while the unmodified silicas are Ultrasil VN2 and VN3. Adding modified silicas increased the optimum curing time and decreased the cure rate index up to a silica content of 20 phr. However, the cure rate index increased with the addition of 40 phr silica. Mechanical testing of the compounds highlighted the impact of silica addition on the reinforcement of the rubber matrix. The incorporation of silica resulted in enhanced mechanical properties, including increased tensile strength, elongation at break, and elastic modulus. The compression behavior of the vulcanized compounds is also analyzed. The results show that the modified silicas with silane coupling agents exhibit lower relative hysteresis loss than the unmodified silicas, highlighting their potential for reducing energy dissipation and improving mechanical efficiency. Additionally, the storage modulus (G') values of the unmodified silicas (VN2 and VN3) are higher than those of the silanized silicas. However, in compounds prepared with 20 phr silica, the differences in storage modulus (G') between the modified and unmodified silicas are minor. Overall, the findings highlight the influence of modified silicas with silane coupling agents and unmodified silicas on the properties of PECH elastomer, providing insights into optimizing silica content for desired material characteristics.