Dynamic-mechanical properties of ethylene/alpha-olefin copolymers preparedby a metallocene catalyst

The influence of comonomer content and type on the dynamic-mechanical behav ior of some ethylene/alpha -olefin (1-hexene, 1-octene, 1-decene, 1-octadec ene and 4-methyl-1-pentene) copolymers was studied. It was observed that th e comonomer content has great influence on alpha- and beta -transitions, bu t almost no influence on gamma -transition. Thus the alpha -transition inte nsity decreases and beta -transition intensity increases as the comonomer c ontent increases. Only 1-octadecene shows a different behavior. At higher c omonomer content, ethylene/1-octadecene copolymer shows two defined transit ions in the alpha -transition region, suggesting the presence of crystals o f different sizes.