Oxysilane polymers from silanediol–bisdimethylaminosilane polycondensations: Synthesis and properties

The solution polycondensation of 1,4‐bis(hydroxydimethylsilyl)benzene with six bis(dimethylaminosilanes) was carried out by the aminosilane deficient method to give a series of high polymers. The bis(dimethylaminosilanes) were bis(dimethylamino)dimethylsilane, bis(dimethylamino)methylphenylsilane, bis(dimethylamino)diphenylsilane, 1,4‐bis(dimethylaminodimethylsilyl)benzene, 1,3‐bis(dimethylamino)‐1,1,3,3‐tetramethyldisiloxane, and 1,5‐bis(dimethylamino‐1,1,3,3,5,5‐hexamethyltrisiloxane). The condensation of dihydroxymethylphenylsilane with bis‐(dimethylamino)methylphenylsilane to give polymethylphenylsiloxane was also performed. A detailed description of the monomer syntheses and polymerization reactions is provided, since this paper represents the first detailed and systematic description of this polycondensation as an alternative to disilanol or disilanol‐dichlorosilane condensation routes. The thermal properties (i.e., T g , TGA, DSC) of poly(p‐phenylenetetramethylsiloxane) are compared to those of poly[1,4‐bis(oxydimethylsilyl)benzenel] (where a Si(Me) 2 O group has been inserted between the silylphenylene units) as well as others in this series, polydimethylsiloxane, and polymethylphenylsiloxane. Similarly, these properties are compared with those of related polymers which include in‐chain ferrocene units. Introduction of Si(Me) 2 O units into poly(tetramethyl‐ p ‐silylphenylenesiloxane) systematically decreases T g and thermal stability. Replacing SiCH 3 with SiC 6 H 5 groups increases T g and thermal stability. Replacing in‐chain C 6 H 4  with ferrocene increases T g and slightly decreases thermal stability. The values of K and A in the Mark‐Houwink equation were determined for several polymers.