Morphology development and thermal degradation of dynamically cured ethylene-octene copolymer/organoclay nanocomposites

Abstract

Ethylene-octene copolymer (EOC)/organically modified Montmorillonite (OMMT) nanocomposites were prepared by melt mixing method in an internal mixer. The nanocomposites were then dynamically cross-linked with 0.25, 0.5, 0.75 and 1wt% dicumyl peroxide (DCP). The results of low angle X-ray diffraction and transmission electron microscopy (TEM) micrographs demonstrated that the OMMT platelets were mainly intercalated by EOC. According to our findings, a mechanism has been proposed for the separation of OMMT layers from each other upon cross-linking. Thermogravimetric analysis (TGA) showed that the OMMT incorporation enhanced the thermal degradation of EOC. A schematic diagram was also prepared to show the main steps of EOC and the nanocomposites degradation with temperature under N2 and air atmospheres. Moreover, it was found from the rheological results that all of the cross-linked nanocomposites behaved as shear thinning fluids over the entire range of frequency. The molecular weight between cross-links (Mc) was estimated using James-Guth as well as Mooney-Rivlin theory. The results indicated that Mc decreased with increasing of the curing agent.