Structure-Property Relationships of Non-Alternating Ethylene-CO Copolymers

We are investigating the use of random ethylene–CO (E–CO) copolymers produced via coordination-insertion catalytic copolymerization as alternatives to multilayer packaging. These random E–CO copolymers are linear and highly crystalline, with carbonyl content varying from 0 to 50%. The copolymers are anticipated to exhibit mechanical properties comparable to polyethylene (PE) while offering improved barrier properties against oxygen. Here, we have characterized the structure-property relationships of E–CO copolymers with varying carbonyl content using a variety of techniques. Differential scanning calorimetry experiments indicated that the melting point of random E–CO copolymers was similar to that of PE. However, wide-angle x-ray scattering demonstrated the presence of two crystal phases in the copolymers. Finally, preliminary analysis of the oxygen permeability through molded films of non-alternating E–CO copolymers confirmed that addition of carbonyl groups to the main polymer chain decreased oxygen permeability.