Synthesis of hydroxy-terminated, oligomeric poly(silarylene disiloxane)s via rhodium-catalyzed dehydrogenative coupling and their use in the aminosilane-disilanol polymerization reaction

摘要

A series of oligomeric, hydroxy-terminated silarylene-siloxane prepolymers of various lengths were prepared via dehydrogenative coupling between 1,4-bis(dimethylsilyl)benzene [H(CH3)(2)SiC6H4Si(CH3)(2)H] and excess 1,4-bis(hydroxydimethylsilyl)benzene [HO(CH3)(2)SiC6H4Si(CH3)(2)OH] in the presence of a catalytic amount of Wilkinson's catalyst [(Ph3P)(3)RhCl]. Attempts to incorporate the diacetylene units via dehydrogenative coupling polymerization between 1,4-bis(dimethylsilyl)butadiyne [H(CH3)(2)Si-CdropC-CdropC-Si(CH3)(2)H] and the hydroxy-terminated prepolymers were unsuccessful. The diacetylene units were incorporated into the polymer main chain via aminosilane-disilanol polycondensation between 1,4-bis(dimethylaminodimethylsilyl)butadiyne [(CH3)(2)N-Si(CH3)(2)-CdropC-CdropC-(CH3)(2)SiN(CH3)(2)] and the hydroxy-terminated prepolymers. Linear polymers were characterized by Fourier transform infrared, H-1 and C-13 NMR, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis, and they were thermally crosslinked through the diacetylene units, producing networked polymeric systems. The thermooxidative stability of the networked polymers is discussed. (C) 2002 Wiley Periodicals, Inc. [References: 32]