| Summary: | Novel blends of acrylonitrile butadiene rubber (NBR) and polyurethane-silica (PU-SiO2) hybrid networks have been prepared by melt blending. The PU-SiO2 hybrid networks were formed via the reaction of NCO groups of NCO-terminated PU prepolymer and OH groups of SiO2 in the absence of an external crosslinking agent (i.e. alcohols and amines) during the curing process of NBR. Both in the neat PU-SiO2 system and the NBR/(PU-SiO2) system, the NCO-terminated PU prepolymer could be crosslinked by SiO2 to form PU-SiO2 hybrid networks. The effects of PU-SiO2 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-SiO2. Transmission electronic microscopy (TEM) studies indicated that the interpenetration and entanglement structures between NBR and PU-SiO2 increased with increasing PU-SiO2 content and the quasi-interpenetrating polymer networks (quasi-IPN) structures were formed when the PU-SiO2 was 50 wt% in the NBR/(PU-SiO2) systems. The microstructures formed in the blends led to good compatibility between NBR and PU-SiO2 and significantly improved the mechanical properties, abrasion resistance and flex-fatigue life of the blends.
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