Structural transformations of certain polyheteroarylenes in the process of thermal aging

Autor: Bondarenko, E. M., Rodé, V. V., Korshak, V. V.
Zdroj: Russian Chemical Bulletin; January 1969, Vol. 18 Issue: 1 p56-62, 7p
Abstrakt: 1.The processes that occur in polyheteroarylenes at temperatures preceding the beginning of weight losses were studied.2.When polyheteroarylenes are heated under vacuum to 200°C there is an increase in the molecular weight, associated with the process of condensation of the terminal groups. Above 200°C, structuration predominates, manifested initially in the formation of branched, and then of crosslinked structures.3.The principles of the formation of crosslinked structures were established for the example of poly-1,3,4-oxadiazole based on phthalidedicarboxylic acid (polymer I), and the nature of the accumulation of crosslinks was followed. It was shown that there is a limit of the content of the gel fraction.4.The values of the thermodynamic parameter of the polymer-solvent interaction of the fractions of polymer (I) with tetrachloroethane were measured. The dependence of the intrinsic viscosity of the polymer (I) on its molecular weight was found.
Databáze: Supplemental Index