Acta Phys. -Chim. Sin. ›› 1993, Vol. 9 ›› Issue (05): 604-609.doi: 10.3866/PKU.WHXB19930507

• ARTICLE • Previous Articles     Next Articles

The Effect of Mobility of Molecules on Radiation-induced Chain Scission and Racemization of iso-Poly(Methyl Methacrylate)

Luo Yun-Xia; Yang Hong; Yu Bin; Ding Meng-Xian; Jiang Bing-Zheng   

  1. Changchun Institute of Applied Chemistry, Academia Sinica, Changchun 130022
  • Received:1992-03-24 Revised:1992-07-16 Published:1993-10-15
  • Contact: Luo Yun-Xia

Abstract: The radiation-induced chain-scission and racemization of isotactic poly(methylmethacrylate)(iso-PMMA) in amorphous and semi-crystalline state as well as in solution have been studied with nuclear magnetic resonance and molar mass deter-mination. It is shown that the chain-scission is dominant for iso-PMMA in dilute solution while the racemization reaction is not favorable in this case. On the contrary, the racemization is favorable when iso-PMMA was irradiated in its crystalline state while chain-scission is not. Such experimental results could be well explained by the mobility of molecules and "cage effect". The hypothesis, we proposed previously that the chain-scission, racemization and recombination are in competition and the final result depends on the state of molecular motion at which iso-PMMA was irradiated, has been verified verified once again.

Key words: Racemization, Chain-scission, Radiation effect, Poly(methyl methscrylate), Molecular mobility