Comparison of properties of colorless and transparent polyimide films using various diamine monomers

Abstract Six different types of polyamic acids were synthesized by reacting 1,2,4,5-cyclohexanetetracarboxylic dianhydride with the diamine monomers 3,4-oxydianiline, 1,3-bis(3-aminopheno- xy )benzene, 1,4-bis(4-amino-phenoxy)benzene, m -bis[4-(3-aminophenoxy)phenyl]sulfone, p -bis[4-(4-aminophenoxy)-phenyl]sulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. Thereafter, polyimide (PI) films prepared via various heat treatment processes. The used in this study for synthesis colorless transparent PI (CPI) characterized a bent meta-structure or para-linear chain containing ether (–O–) bonds. In addition, some included fluorine (–CF 3 ) substituents sulfone (–SO 2 –) groups. Furthermore, thermal mechanical properties, optical transparency, solubility CPI six monomer structures investigated. correlation between film properties related was specifically emphasized.