Synthesis, characterization and properties of novel thermally stable copoly(amide-imide)s containing dimethylsilane moieties

New type of poly(amide-imide)s were prepared based on novel diacid monomer containing softening siloxane groups. Bis(p-aminophenoxy) dimethyl silane (3) was prepared by the reaction of dimethyl dichlorosilane with p-aminophenol in toluene. N,N'-Bis(4-trimellitimidophenoxy) dimethylsilane (5) as a novel aromatic dicarboxylic acid containing silicone moiety was synthesized by condensation of bis(p-aminophenoxy) dimethylsilane with trimelitic anhydride in acetic acid. The structure of diacid 5 was confirmed using various spectroscopy methods. The direct polycondensation technique was used for the polyamidation of monomer 5 with several aromatic diamines using pyridine / 2-methylpyrrolidone / triphenyl phosphite / CaCl2 as condensing agent. The resulting novel poly(amide-imide-siloxane) s were obtained in high yields and inherent viscosities. These polymers were characterized using FT-IR, H-1-NMR, thermogravimetric and elemental analysis techniques. The results show that silicone modified poly(amide-imide)s show high solubility and excellent thermal stability.