Molecular mobility in crystallising aromatic thermoplastic polyimide R-BAPS

Abstract

The molecular mobility of the thermoplastic aromatic R-BAPS polyimide films based on 1,3-bis (3,3’-4,4’-dicarboxyphenoxy) benzene (dianhydride) and 4,4’-bis (4-aminophenoxy) biphenyl was studied using the dielectric method. Two relaxation regions of dipole polarisation caused by local mobility of phenylene groups in the diamine (γ process) and in the diamine and dianhydride macromolecule parts (β process) were identified in the glassy state, In the high-elastic state, two relaxation processes, α and αMWS, were also observed. The α process is due to the large-scale segmental mobility of macromolecules. The αMWS process is caused by the relaxation at the boundary between amorphous and crystalline regions, i.e., the Maxwell-Wagner-Sillars relaxation. Moreover, a structural transition due to melting was observed in the initial samples.