Synthesis and properties of hyperbranched polyimides from A _2+ B'B _2 monomers and A _2+ B'B _2 + B _2 monomers with various comonomer ratios

摘要

A series of hyperbranched polyimides were successfully synthesized by A _2 + B'B _2 approach based on 2,4,6-triaminopyrimidine(TAP) and biphenyl dianhydride (BPDA), The resulting polyimides were characterized by FTIR, SEC/MALLS, NMP, DSC, TGA. The results showed that BPDA-TAP hyperbranched polyimides had poor thermal stability. In accord with this fact, difunctional B2 como-noer (4,4'-oxydianiline(ODA))was added into the polymer structure to improve heat resisting property of HBPIs by incorporation. This approach could be described as A2+ B' B _2 + B _2 or more simply A _2 + B _3 + B _2 copolymerization. Both for the BPDA-TAP-ODA and BPDA-TAP hyperbranched polyimides, the amine-terminated polyimides showed higher glass transition temperature and 10 % weight loss compared with the corresponding anhydride-terminated ones, which can be attributed to the different terminal functional groups and the anhydride residues.