CONFORMATIONAL AND PACKING ENERGY CALCULATIONS ON ETHYLENE COPOLYMERS

A conformational analysis was performed on the isolated chains of ethy lene-propene and ethylene-1-butene copolymers. The lowest energy confo rmations in accordance with the chain repeating distance of polyethyle ne were used in packing energy calculations. The results of our calcul ations suggest that both methyl and ethyl groups are tolerated in the crystalline conformation of a single polyethylene chain, but only the methyl group is acceptable in the crystalline state if the packing ene rgies and the lattice deformations are taken into account.