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 8C 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 8C 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 8C do not produce appreciable crosslinking. All these features suggest that these new copolymers could be suitable for possible industrial fabrication processes of XLPE.