Novel blends of acrylonitrile butadiene rubber and polyurethane-silica hybrid networks

Abstract

Novel blends of acrylonitrile butadiene rubber (NBR) and polyurethane-silica (PU-SiO 2) hybrid networks have been prepared by melt blending. The PU-SiO 2 hybrid networks were formed via the reaction of NCO groups of NCO-terminated PU prepolymer and OH groups of SiO 2 in the absence of an external crosslinking agent (i.e. alcohols and amines) during the curing process of NBR. Both in the neat PU-SiO 2 system and the NBR/(PU-SiO 2) system, the NCO-terminated PU prepolymer could be crosslinked by SiO 2 to form PU-SiO 2 hybrid networks. The effects of PU-SiO 2 introduction into the NBR, on the properties of the resulting blends were studied. It was found that the vulcanization was activated by the incorporation of PU-SiO 2. Transmission electronic microscopy (TEM) studies indicated that the interpenetration and entanglement structures between NBR and PU-SiO 2 increased with increasing PU-SiO 2 content and the quasi-interpenetrating polymer networks (quasi-IPN) structures were formed when the PU-SiO 2 was 50 wt% in the NBR/(PU-SiO 2) systems. The microstructures formed in the blends led to good compatibility between NBR and PU-SiO 2 and significantly improved the mechanical properties, abrasion resistance and flex-fatigue life of the blends. © BME-PT.