CROSS-LINKING REACTIONS IN AN UNSATURATED LOW-DENSITY POLYETHYLENE

The peroxide crosslinking properties of a new group of low density pol yethylenes (LDPE), unsaturated LDPE, were investigated. These are copo lymers between ethylene and 1,9-decadiene and contain a higher number of vinyl groups than 'ordinary' LDPE, situated on pendant carbon chain s. Copolymers with different amounts of vinyl groups were crosslinked with dicumylperoxide at 180 degrees C and the crosslinking reaction wa s followed by FTi.r. and gel content measurements. Compared with the r eference material, the unsaturated LDPE crosslinked faster and produce d higher final gel contents. Two crosslinking reactions take part simu ltaneously in the copolymers: polymerization of vinyl groups and combi nation crosslinking, i.e. coupling of macroradicals. (C) 1997 Elsevier Science Ltd.