INTERPENETRATING POLYMER NETWORKS OF POLY(DIMETHYLSILOXANE) .1. PREPARATION AND CHARACTERIZATION

Model networks of alpha,omega-dihydroxy-poly(dimethylsiloxane) (PDMS) were prepared by tetrafunctional crosslinking agent tetraethyl orthosilicate (TEOS) and the catalyst stannous 2-ethylhexanoate. Hydroxyl-terminated chains of PDMS having molecular weights 15 x 10(3) and 75 x 10(3) mol-1 were used in the crosslinking reaction. Bimodal networks were obtained from a 50% (w/w) mixture of PDMS chains with M(n) = 15 x 10(3) and 75 x 10(3) g mol-1. A sequential interpenetrating network of these PDMS chains was also prepared. Physical properties of the elastomers were determined by stress-strain tests, swelling and extraction experiments, and differential scanning calorimetry measurements.