Thermal crosslinking of ethene copolymers containing 1,2-cyclopropane units

The possibility to obtain crosslinked polyethene (XLPE) from new ethene copolymers containing cyclopropane rings (C3), synthesized by ethene/1,3-butadiene copolymerizations with a hindered metallocene catalyst, has been explored. In particular, the thermal crosslinking of these copolymers, for C3 molar content in the range 0.3-2.7%, has been studied for annealing temperatures up to 200 °C and compared with the thermal behavior of other ethene-butadiene copolymers. Only for the ethene-C3 copolymers, the annealing procedures in the temperature range 160-200 °C lead to high gel fractions. These crosslinking processes occur in reasonable times and leave nearly unaltered the polymer crystallinity. Moreover, annealing procedures up to 140 °C do not produce appreciable crosslinking. All these features suggest that these new copolymers could be suitable for possible industrial fabrication processes of XLPE.