Influence of POSS Addition on Properties of Ethylene-Propylene EPM and Hydrogenated Butadiene-Acrylonitrile HNBR Composites Containing Layered Silicate and Nanometric Silica

Polyhedral oligomeric silsesquioxanes (POSS) with functional groups: octavinyl-POSS and octamethacrylate-POSS were applied as additives to ethylene-propylene copolymer (EPM) and hydrogenated butadiene rubber (HNBR). As reinforcing fillers nanometric silica Aerosil 380 and montmorillonite Nanomer I.31 PS were chosen. The POSS modified EPM and HNBR compositions were prepared using melt mixing and they were chemically peroxide crosslinked. Effect of octamethacrylate-POSS and octavinyl-POSS on curing characteristics and mechanical properties was investigated. The rheometric measurements indicated that octavinyl-POSS and octamethacrylate-POSS influenced the curing behavior of rubbers causing increase of crosslink density. The POSS moieties participated via functional groups in curing reactions and cured rubber network formations. Significant enhancement of tensile strength TS and modulus at 100% elongation SE100 resulting from higher density of vulcanizates and nanometric reinforcement generated by grafted POSS particles was observed. The modified HNBR and EPM/HNBR vulcanizates containing methacrylate-POSS characterized higher UV-stability. Additionally the reinforcing effect of octamethacrylate-POSS on properties of EPM/HNBR blends was reported.