Synthesis and characterization of novel silanol-containing polymers and copolymers, novel silanol-containing polymer blends, interpolymer complexes and semi-interpenetrating polymer networks (IPNs).

摘要

Novel 4-vinylphenyldimethylsilanol, 4-vinylphenylmethylphenylsilanol polymers and styrene copolymers were synthesized from their silane precursors by the oxygen atom insertion into the Si-H bond via reaction with dimethyldioxirane. The oxyfunctionalization reaction of the silane by dimethyldioxirane is fast and quantitative. Poly(styrene-co-4-vinylphenyldimethylsilanol) (ST-VPDMS) containing more than 18 mole% 4-vinylphenyldimethylsilanol (VPDMS) were found to have a strong tendency to undergo spontaneous condensation to form siloxanes in the solid state. Poly(styrene-co-4-vinylphenylmethylphenylsilanol) (ST-VPMPS) were found to be stable up to about 200{dollar}spcirc{dollar}C.; Systematic studies of novel silanol-containing polymer blends have been conducted by both T{dollar}sb{lcub}rm g{rcub}{dollar} measurements and FT-IR spectroscopy. Miscible blends were formed for ST-VPDMS/PBMA in the composition range of 4 to 34 mole% VPDMS. For ST-VPMPS/PBMA blends, the miscible blends were formed in the composition range of 9 to 56 mole% VPMPS. The T{dollar}sb{lcub}rm g{rcub}{dollar}-composition relationship of the miscible blends of ST-VPDMS/PBMA and ST-VPMPS/PBMA can be well described by Schneider's third-power equation.; For ST-VPDMS/PVPr blends, interpolymer complexes occurred for the copolymers containing more than 34 mole% VPDMS. The complexes of ST-VPDMS/PVPr were readily converted into molecular penetrated semi-interpenetrating polymer networks (IPNs) by the condensation of the dimethylsilanol without the presence of any external crosslinkers when the copolymers containing more than 60 mole% of VPDMS. For ST-VPMPS/PVPr blends, interpolymer complexes also occurred for the copolymers containing more that 31 mole% VPMPS. The positive deviations of the glass transition temperatures from the weight-average values were found for the ST-VPMPS/PVPr blends. The results were interpreted in terms of the relative strength of the hetero- and self-associated hydrogen bonds and free volume effect.; This research has not only shown that the silanol functional groups are very effective in promoting polymer-polymer miscibility but also demonstrated that the blends with desired properties could be made through the control of the relative strength of the hetero- and self-associated hydrogen bonds which could be manipulated by changing the composition of the copolymers or the substituents bound directly to the Si atom or the acceptor polymers with different hydrogen bond acceptor functional groups.