Improved ethylene-propylene rubber/silica interface via in-situ polymerization

This article demonstrates an effective in-situ method for the preparation of ethylene-propylene rubber/silica composites (EPR/SiO 2 ) via continuous process with two stages: in the first stage, functional olefin monomers containing trichlorosilane group (CSO) are designed and the terpolymerization of ethylene/propylene/CSO catalyzed by metallocene catalyst is implemented; in the second stage, by dispersing the SiO 2 directly into the unterminated polymerization solution , the copolymer chains are anchored to the SiO 2 particles via the reaction between the hydroxyl on SiO 2 surface and pendant chlorosilane groups on the EPR chains. The CSO content in the copolymers was tailored in relatively wide range from 0.71 mol% to 4.68 mol%, which provided various chlorosilane groups for the anchoring reaction on SiO 2 surface. Thus a series of EPR/SiO 2 chemical composites (with the SiO 2 content of 13 wt% ∼ 85 wt%) were prepared via the highly efficient elimination reaction between Si-Cl and Si-OH groups. The dispersing morphology and stability of SiO 2 in EPR/SiO 2 composites were compared with that of the physically blended EPR/SiO 2 systems. Owing to the covalent bonding between polymer chains and SiO 2 particles, the problem of compatibility between the rubber and the filler was fundamentally solved.