Low dielectric and thermal properties of polyimides based on PMDA, BPADA, TPE-Q and TPE-R

The polyimides were prepared by pyromellitic dianhydride (PMDA) or 4,4'-(4,4'-Isopropylidenediphenoxy)diphthalic anhydride (BPADA) as dianhydride monomer and 1,4-bis(4-aminophenoxy)benzene(TPE-Q) or 1,3-bis(4-aminophenoxy)benzene(TPE-R) as diamine monomer. The polyimides were well characterized by FT-IR, thermogravimetric analysis, dynamic thermomechanical analysis, dielectric measurement and tensile test. The flexibility of polyimide molecular chain was judged by the comparison of molecular volumes, molecular length and conformation transition energy through molecular simulations.