THERMAL AND MECHANICAL PROPERTIES OF GRADIENT COPOLYMERS CONTAINING ETHYLENE AND 5-NORBORNEN- 2YL ACETATE

The new catalyst is capable of homopolymerizing ethylene to hydrophobic polyethylene as well as copolymerizing ethylene with functionalized monomers such as 5-norbornen-2-yl monomers with high molecular weights and narrow molecular weight distributions. 2 With this nickel catalyst system, it will be also possible to attain interesting polymer architectures such as block copolymers, random copolymers, gradient copolymers (see, for example, ref 3 and 4 for the detail of the structure on gradient copolymers), star-shaped polymers and end-functionalized polymers. In this paper, we will focus on the research of the gradient copolymers. The polymeric structure of the gradient copolymers is amorphous and highly polar at the beginning and tapers to a semi-crystalline polyethylene (PE)-like structure at the chain end. We will discuss the morphology of the newly synthesized gradient copolymers, comparing it with the resultant mechanical properties that were found to be highly related to the original chemical structures of the tapered copolymers.