STUDYOFPOSITRONANNIHILATION AND SOMEPHYSICAL PROPERTIES OF SOME POLYMFRS

Abstract

In this thesis, the effect of incorporation of GPF-carbon black on the free volume properties as well as the Doppler broadening parameters has been investigated for Natural Rubber/Styrene Butadiene Rubber (NRISBR) composites. It is found that, the free volume decreases with increasing percentage of additive, and as the size of the free volume decreases, the W-parameter, which corresponds to high momentum region, should decrease and the S-parameter should increase. The dielectric behaviour of the tested composites has been studied in the frequency range from 1OOHz to 1OOKHz and temperature range from 30 to 140 'C. It has been found that Maxwell-Wagner-Sillars (MWS) effect is the most effective factor in the range of frequency investigated. The experimental data has been fitted in view of the current theoretical models. Furthermore, the d.c.electrical conductivity, mechanical and swelling behaviour have been also investigated. The analysis of positron annihilation parameters introduces a trusted support for the interpretations of the other macroscopic physical properties.