SYNTHESIS, CHARACTERIZATION, AND SOLUBILITY BEHAVIOR OF POLYSILOXANES WITH 4-(DIALKYLAMINO)PYRIDINE FUNCTIONS

New silane monomers, which contain the 4-(dialkylamino)pyridine (DAAP) function, have been synthesized by hydrosilylation of 4-(N-methylallylamino)pyridine with Me(n)Si(OEt)3-nH(n = 0, 1) and 4-(diallylamino)pyridine with Me(n)Si(OEt)3-nH(n = 0-2) using H2PtCl6 as a catalyst. Only beta-addition products were observed. The products were characterized by elemental analysis, infrared and H-1 and C-13 NMR spectroscopy, and gas chromatography-mass spectrometry. Hydrolysis-polycondensation of the respective difunctional monomers with a basic catalyst gave a mixture of linear homopolymer and cyclic oligomers from the monomer with a pendant DAAP residue and only the linear homopolymer from the monomer with the in-chain DAAP residue. The linear homopolymers were trimethylsiloxy end-blocked by reaction with (Me3-Si)2NH or bis(trimethylsilyl)acetamide. The end-blocked homopolymers were characterized by spectroscopic and thermal analytical methods. Thermal analysis (TGA) of the linear homopolymers indicates remarkable thermal stability (T(d) > 400-degrees-C) comparable to that of poly(dimethylsiloxane). Molecular weights for the pendant and in-chain polymers were determined by end-group analysis from the H-1 NMR spectra and exclusion chromatography. The mass spectra of the homopolymers above the degradation temperature indicate depolymerization, giving rise to a cyclic monomer and cyclic oligomeric products. The two linear homopolymers have different and unusual solubility properties in immiscible H2O/CH2Cl2 medium. The effect of pH on solubility and partition behavior of both polymers is discussed. Cross-linked homopolymers were prepared by established procedures.