GB1027577A - Organo silicon polyimides - Google Patents

Abstract

An organosilicon polyimide is made by reacting (A) 45 to 55 mole per cent of an aromatic compound having at least 3 carboxyl groups per molecule in the form of carboxylic acid, ester or anhydride groups, at least 2 of these groups being attached to adjacent C atoms in the same aromatic ring, with (B) 45 to 55 mole per cent of a compound of the formula <FORM:1027577/C3/1> in which each R is a monovalent saturated or unsaturated hydrocarbon, halohydrocarbon or hydrolysable radical other than halogen, each U is a divalent hydrocarbon or substituted hydrocarbon radical optionally interrupted by O, S or N, and n has an average value from 1 to 100. Numerous examples of reactant (A) are given, some of which contain sulphone or ether groups. The optional hydrolysable radicals in (B) may be alkoxy, aroxy, acyloxy, H or -O-N=C(R11)2. The reaction is suitably effected in a polar solvent or a combination of a polar and a non-polar solvent, and under anhydrous conditions at a temperature below 70 DEG C. In a typical Example (1), pyromellitic dianhydride was reacted with Ph2Si(OCH2.CH2.NH2)2 in dimethylformamide at a temperature below 60 DEG C. Reactant (B) is preferably made by transesterification, such as R2Si(OMe)2 + 2H2N-U-OH - \sY 2MeOH + R2Si(O-U-NH2)2, in the presence of tetraisopropyl titanate and removing methanol from the reaction mass. In preparations (A) and (B), Ph2Si(OCH2CH2.NH2)2 and Ph.MeSi(OCH2.CH2.NH2)2 were made in the above manner.