The effect of wheat hay on carbon black loaded EPDM composite studied by positron annihilation lifetime spectroscopy

Abstract

The positron annihilation lifetime (PAL) technique has been applied to investigate the behavior of free volume hole in carbon black loaded ethylene propylene diene monomer (EPDM) composite as a function of the wheat hay concentration from 10 to 50 phr. The macroscopic studies including stress-strain, hardness and swelling behavior were measured too. An attempt is done to establish a correlation between the macroscopic measurements and the microscopic properties of the free volume holes. The ortho-positronium (o-Ps) parameters show a compact phase around 20 phr concentration of wheat hay. Such a phase is thought to be responsible for the maximum values of hardness, rupture stress, rupture strain and the minimum in the degree of swelling.