Synthesis and Characterization of polyimides derived from 5-amino-2(p-aminophenyl) benzoxazole monomer

摘要

Polyimides prepared from 5-amino-2(p-aminophenyl) benzoxazole (AAPB) with pyromellitic dianhydride(PMDA), 2,2'3,3'-biphenyl tetracarboxylic dianhydride(i-BPDA), 4,4'-oxdiphthalic anhydride(ODPA), l,4-bis(3,4-dicarbosyphenoxy) benzene dianhydride(HQDPA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) were synthesized successfully via a conventional two-stage method. Their structures and properties were characterized by FT-IR, DSC, TG and XRD. The intermediate poly(amic acid)s had inherent viscosity range of 0.86-2.18 dL/g and could be thermally converted into light yellow polyimide films. The polyimides showed excellent solvent resistance and good thermal stability. The glass transition temperatures (T_g) were found to be 336°C~369 °C .The decomposition started at a temperature above 530°C in N_2 atmosphere.