Effect of the SO2 group in the diamine fragment of polyimides on their structural, thermophysical, and mechanical properties

Experimental and theoretical investigations, including an all-atom computer simulation, are performed for block samples of thermoplastic polyimides, amorphous R-BAPS (based on R dianhydride 1,3-bis(3??,4-dicarboxyphenoxy)benzene and diamine BAPS 4,4??-bis(4??-aminophenoxy)biphenyl sulfone), and crystallizable R-BAPB (based on R dianhydride and diamine BAPB 4,4??-bis(4??-aminophenoxy)biphenyl), which differ in either the presence or absence of the sulfone group in the repeating unit of the polyimide macromolecule. The features of thermophysical, structural, and mechanical properties of R-BAPS and R-BAPB are related to the formation of associates from sulfur and oxygen atoms of the sulfone group that are stabilized by electrostatic interactions.