Influence of defects in the chemical structure of polyimides on their thermal stability

Abstract

The thermal stability of a number of polyimides has been estimated as a function of the composition of the model polyimide-defect type copolymer. It is shown that repeat-unit heterogeneity leads to lower thermal stability. Features of changes in thermal stability and heat resistance, where various chemical modification are involved, show that depending on their nature and geometry the same defects (bridge groups) may have contrary effects on thermal characteristics. This must be taken into account when polyimide properties are being predicted.