Long-Spaced Aliphatic Polyesters

Long-spaced aliphatic model polyesters were synthesized by acyclic diene metathesis (ADMET) copolymerization of undec-10-en-1-yl undec-10-enoate and undeca-1,10-diene followed by exhaustive hydrogenation. Resulting polyesters contained 52.6 to 0.9 ester groups per 1000 methylene units, randomly distributed in the polyethylene main chain. Melting points of these materials quantitatively agree with an inclusion model and decrease linearly vs linear polyethylene with the mole fraction of ester groups. By comparison to methyl branched polyethylenes and regularly spaced long-chain A2 + B2 polyesters, these findings can be related to steric demand and regular versus nonregular spacing of polar ester groups in crystallized polyester chains, respectively.