Formation of branched structure of polyimide macromolecules in the temperatures range below the onset of the thermal destruction

Abstract

The film samples of poly-[4,4'-bis(4"-N-phenoxy)biphenyl-sulfone]imide1,3-bis(3',4-dicarboxyphenoxy)benzene obtained both by two-step synthesis and by onestep high temperature synthesis in N-methyl-2-pyrrolidone solution were used to study the formation of the interchain crosslinks in this soluble polyimide in the temperature range of 250-300°C. Just in this region a final stage of the thermal treatment of different polyimide materials takes place during their processing. A possible crosslink formation mechanism has been put forward to present the adequate explanation of the experimental data obtained in the work. A simple technological way is offered to avoid the unfavourable effect above. *Correspondence to: Iosif Gofman, Institute of Macromolecular Compounds, Russian Academy of Sciences, 31, Bol’shoi str. (V.O.), St. Petersburg, 199004, Russia, Tel: +7(812)328-8511; E-mail: gofman@imc.macro.ru