Effect of Radiation on Some Polymeric Materials

Abstract

The obtained results throughout this work may be presented in the following two main parts: I. Structure-property Behaviour of Gamma-Irradiated Poly(styrene) and Poly(methyl methacrylate) Miscible Blends. In this part, polymer blends based on various ratios of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) were prepared by the casting solution technique using benzene as a cosolvent. The prepared blends were exposed to various doses of gamma radiation up to 25 Mrad. The stmcture-property behaviour of the polymer blends before and after they had been irradiated was investigated by DSC, TGA, FTIR spectroscopy, and scanning electron microscop (SEM). The results of this part may be summarized in the following points: 1. PS/PMMA blends as composed of radiation sensitive polymer (PMMA) and a radiation resistance polymer (PS) were shown to be highly compatible over a wide range of ratios, as seen by the visual observation. The results presented in this work demonstrate the effect of gmmna radiation on the glass transition temperature behaviour. DSC scans of the glass transition temperature of a series of polymer blends containing various ratios of PMMA and PS indicated a single Tg over the studied compositions. Upon exposure of the PS/PMMA blends to gamma irradiation a further depression in Tg was observed, particularly with polymer blends rich in PMMA ratios. The drop in Tg occurring at high doses of 25 Mrad was attributed to the degradation of the PMMA component.