The formulation of polymers by polymerization-polycondensation processes: polyimide based systems

Radical chain (co)polymerization of a set of acrylates containing dissolved high performance polymers, namely fluoropolyimide, is performed. Based on the study of the structure and properties of the polymers (elemental compos ition, solubility, molecular weight parameters, etc) it is proposed that th e copolymer formation reaction takes place due to a transfer chain reaction on the polyimide. The influence of acrylate (ethyl-, n-butyl-, methyl-alph a- fluoro-, ethyl-alpha-fluoro-, methyl-glycidyl-, butyl-, hexafluoro-iso-p ropylmethacrylate) and polyimide content on the properties of the copolymer s obtained is studied. Clear and opaque, hard and elastic materials are obt ained. These polymers differ in their characteristics from the relevant pol yacrylates and their blends with polyimide prepared by the usual method of mixing. One-step catalytic polycondensation of diamines and tetracarboxylic acid dianhydrides in a solution of preformed polyimide is studied. It is s hown that such a procedure influences the structure and properties of polyi mides formed in situ.