Influence of the type and the comonomer contents on the mechanical behavior of ethylene/alpha-olefin copolymers

The influences of the type and concentration of alpha-olefin (1-hexene, 1-o ctene, 1-decene, 1-octadecene, 4-methyl-1-pentene) on the mechanical behavi or and crystallinity degree of some ethylene/alpha-olefin copolymers obtain ed by metallocene catalysts were studied by means of stress/strain experime nts. The crystallinity degree of these copolymers has been determined by X- ray measurements. It has been observed that the copolymers show less resist ance to strain as the comonomer content increases and the crystallinity dec reases. Most of the studied copolymers exhibit a significant increase in th e crystallinity level after the stress/strain experiments. (C) 1999 John Wi ley & Sons, Inc.