REACTIVE PROCESSING OF POLYETHYLENE AND POLY(ETHYLENE-CO-VINYL ACETATE)

The progress of crosslinking reactions in the system low-density polyethylene/ethylenevinylacetate initiated by peroxide (1 wt.-% dicuinylperoxid) was investigated. The reaction was carried out in a quasi-closed mixing chamber and the yield observed by measuring the temperature-corrected-torque. The temperature and the evolutions per minute were changed step by step for the investigation of the influence of the processing conditions on the crosslinking kinetics. Both the increase of temperature and of rotor speed accelerated the radical reaction. The result of crosslinking of the pure components and of the LDPE/EVA compound was a decrease of cristallinity. Therefore, the dynamic E-modul falls though a crosslinking reaction took place. The results were strongly influenced by the existing melt-morphology in the state before the radicals attacked the polymers. The melt morphology in the previous state determines also the yield, the resulting morphology and the mechanical properties.