COPOLYMERIZATION OF ETHYLENE WITH ALPHA-OLEFINS AT HIGH-TEMPERATURE AND CHARACTERIZATION OF COPOLYMERS

Ethylene copolymerizations were performed with butene-1,4-methylpenten e-1 (4MP1), hexene-1, and octene-1 at a high temperature. Comonomer in corporation is markedly poor for 4MP1, but there are negligible differ ences among the other comonomers. The densities of copolymers having t he same comonomer mole content increase with a decrease of molecular w eight of the comonomers, whereas the melt temperature of the copolymer s decrease except for 4MP1 which has the highest melt temperatures. Fr om an analysis of the copolymers by TREF combined with GPC and C-13-NM R, it is assumed that the copolymers from heavier comonomers comprise heptane-soluble amorphous copolymers and ethylene-rich semicrystalline ones which lead to lower densities and higher melt temperatures, resp ectively. Therefore, it can be said that heavier comonomers (4MP1 in p articular) tend to be incorporated more heterogeneously, resulting in a wider distribution of comonomer composition.