Study of Electron Beam Pre-Irradiation on Char Yields of Polyacrylonitrile

Abstract

Thermal treatment of polyacrylonitrile (PAN) with different molecular weights pre-irradiated by electron beam was prepared to study the radiation effects on thermal behaviors. Thermal properties were characterized by thermogravimetric analyses. Char yields (800 oC) of PAN samples are increased remarkably with the increase of irradiation dose, and all samples can obtain the similar high char yields (~57 %) at the dose of 300 kGy. FTIR and UV-visible absorption spectra of pre-irradiation PAN illustrate the formation of –HC=N-N=CH-crosslinking conjugation across the polymeric chains, which can improve PAN’s thermal behaviors. Char yields of pre-irradiated PAN samples are mainly dominated by their gel contents, and they are almost independent of the molecular weights of PAN samples.