HEAT STABLE BLOCK COPLYMER HAVING (IMIDE-AMIDE)BLOCK-(UREA-SILOXANE)BLOCK STRUCTURE

摘要

Novel thermally stable block copolymers containing (imide-amide) and (urea-siloxane) blocks. …??More precisely, these copolymers are obtained by a chain sequence of the following two stages:… - stage (a): preparation of an oligomer containing end N=C=O groups from an aromatic diisocyanate and a monoanhydride of an aromatic tricarboxylic acid, and… - stage (b): reaction of the said oligomer with a diamine of formula: …IMAGE… in which: X denotes: …IMAGE… each of R1, R2, R3, R4 and R5 denotes a hydrocarbon radical, x is a number ranging from 2 to 8 and the sum y + z is between 0 and 100. …??These copolymers are employed especially for the production of coating films.