Polyimide having organopolysiloxane side chain

A method for the preparation of a polyimide which contains organopolysiloxane side chains, said method comprising:

• (i) silylating
• (a) an organopolysiloxane having diaminobiphenyl group of the formula I ##STR20## wherein m is 0 or 1 and Z is an organopolysiloxane group represented by the formula II ##STR21## in which R.sup.1 is a divalent organic group having at least 2 carbon atoms, R.sup.2 through R.sup.6 are the same or different monovalent organic groups and n is an integer having a value of at least 1, and, optionally,
• (b) an aromatic diamine with a compound selected from the group consisting of a trialkylhalosilane and a nitrogen-containing silylation agent;
• (ii) reacting the silylated compounds from step (i) with
• (c) an aromatic tetracarboxylic acid dianhydride in a solvent to obtain a silylated polyamide acid having organopolysiloxane side chain with repeating units shown by the formulas VIII and IX ##STR22## in which R.sup.8 is an alkyl group, A.sup.1 is a tetravalent aromatic group, A.sup.3 is a divalent aromatic group and A.sup.2 is a divalent organic group shown by the formula V below, ##STR23## in which Z and m have their previously defined meanings, the molar ratio of repeating unit VIII to repeating unit IX being in the range 100:0 to 1:99, (iii) carrying out a thermal imidization of the product obtained in step (ii).