Cross-linking of ethylene-octene copolymer (EOC) by dicumyl peroxide (DCP)

Abstract

Ethylene-octene copolymer (EOC) was crosslinked by dicumyl peroxide (DCP) at various temperatures (150-200 degrees C). Six concentrations of DCP in range 0.2-0.7 wt % were investigated. cross-linking was studied by rubber process analyzer (RPA) and by differential scanning calorimetry (DSC). From RPA data analysis real part modulus s`, tan delta, and reaction rate were investigated as a function of peroxide content and temperature. The highest s`(max) and the lowest tan d were found for 0.7% of DCP at 150 degrees C. Chain scission was analyzed by slope analysis of conversion ratio, X in times after reaching the maximum. Less susceptible to chain scission are temperatures in range 150-170 degrees C and peroxide levels 0.2-0.5%. Heat of reaction was analyzed by DSC at various heating rates (5-40 degrees C min(-1)). It was found to be exothermic. By projection to zero heating rate, the reaction was found to start at 128 degrees C with the maximum at 168 degrees C. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 521-530, 2011