Elastomers based on α,ω-dihydroxy-polydimethylsiloxane/polystyrene blends:: Morphology and mechanical properties

alpha,omega-Dihydroxy-polydimethylsiloxan /polystyrene (PDMS/PS) blends were prepared by the bulk polymerization of styrene (St) in the presence of alpha,omega-dihydroxy-polydimethylsiloxane (PDMS), using benzoyl peroxide (BPO) as initiator. The PDMS/PS blends obtained by this method are a series of stable, white gums, which were vulcanized to elastomers at room temperature with methyltriethoxysilicane (MTES). The MTES dosage was much larger than the amount necessary for end-linking hydroxyterminated chains of PDMS, with the excess being hydrolyzed to crosslinked networks, which were similar to SiO2 and acted as filter. Investigations were carried out on the elastomeric materials by extraction measurement and scanning electron microscopy. The extraction data show that at each composition the sol-fraction is less than expected. Scanning electron microscopy observation demonstrates that the elastomer has microphase-separated structure consisting of PS domains within a continuous PDMS matrix, and the extracted material exhibits a porous structure. Moreover, the mechanical properties of the elastomers were studied in detail. (c) 2006 Wiley Periodicals, Inc.