Synthesis of polyethylene/polyester copolymers through main chain exchange reactions via olefin metathesis

The synthesis and characterization of linear polyethylene/polyester copolymers produced by olefin cross metathesis and subsequent catalytic hydrogenation are described. The success of the scrambling reaction between 1,4-polybutadiene and unsaturated polyester via olefin cross metathesis was confirmed by ¹H NMR. Differential scanning calorimetric (DSC) measurements indicated that the size of the copolymer blocks varied gradually with the exchange ratio. Catalytic hydrogenation of the unsaturated copolymers with different exchange ratios was carried out using Pd-Al₂O₃. The crystallinity of the resulting hydrogenated polymers depended on the exchange ratios achieved during olefin cross metathesis. This suggests that the unique sequential structure imparted to the unsaturated polymers during metathesis was retained during the hydrogenation process.