The degree of crosslinking of LDPE-ethylene/propylene/norbornene terpolymer blends
in relation to annealing temperature and blend component proportions
Polimery 2001, No 6, 414
SummaryThe crosslinking degree was studied in relation to the terpolymer proportion in the blend and annealing temperature. The reactions were run at a temperature from within the range 1l0-180°C in the presence of 1,1-di-tert-butylperoxy-3,5,5-trimethylcyclohexane as crosslinker and triallyl cyanurate as crosslinking controller (Figs. 1-9). The crosslinking degree was determined by measuring the eontent of the crosslinked fraction (extraction with boiling xylene) or by a vulcametric method (measurement of torsiorial moment M). With the crosslinker used in idenfical arnounts. the degree of crosslinking of LDPE was higher than that of the terpolymer. As the terpolymer proportion in the blend was raised, the degree of crosslinking decreased, but not in direct relation. When added in a small amount, the controller was found to reduce the crosslinkability of LDPE and to enhance that of the terpolymer. The blends cross-linked with the controller added shawed the xylene-insaluble fractian ta attain a minimum, when the terpolymer proportion was 60 weight parts. The results suggest the crasslinking of LDPE and of the terpolymer to fallow different mechanisms and the two palymers to fail to cross-link with each other in the blend.