On the new chemical nomenclature

Abstract

This paper reports a study of a polymer sequence, and the striking changes with stereochemical configuration in polymethyl methacrylate (PMMA) by radiation-induced polymerization. The polymer structure was investigated by means of 13C NMR spectroscopy, showing that carbon-13 spectra were interpreted in terms of pentad sequences for the CO resonance; the spectrum reveals seven separate resonance lines, which can be assigned to the ten possible pentads. Comparison of the observed and calculated intensities of the assigned resonances indicated that the Bernoullian statistic describes the radiation-induced polymerization mechanism of the PMMA sample under study. The experimental results show the radiation induced dose and the probabilities of isotactic, syndiotactic and heterotactic triads are a function of Pm, respectively. The preference of the propagation or degradation for the syndiotactic in PMMA can be found due to the activation enthalpy and dependence of radiation dose. The difference in the free activation enthalpies is from 923 cal/mol to 773 cal/mol with higher activation entropy in the growth step. Molecular weights of PMMA by various radiation dose in polymerization were determined by GPC. The authors have estimated the N-ads distinction equation, and by using this distinction equation satisfactory results have been obtained. The Bernoullian process can then be distinguished.