High-Molecular-Weight Polyesters Mimicking Linear Low-Density Polyethylene: Mechanistic Insight and Structure–Property Relationship

This work describes the synthesis of aliphatic hydrocarbon macrodiols and their use as building blocks in the synthesis of linear low-density polyethylene-like (LLDPE-like) polyesters. Ring-opening metathesis polymerization of cyclooctene and 3-hexylcyclooctene in the presence of (Z)-but-2-ene-1,4-diyl diacetate as a functionalized chain transfer agent (CTA), followed by hydrogenation, afforded macrodiols with varying amounts of branches. A mechanistic study revealed that the polymerization of 3-hexylcyclooctene is hampered by steric hindrance and requires at least two monomer regio-misinsertions per polymer chain. Using 10-undecen-1-ol as CTA greatly simplified the synthesis of the α,ω-dihydroxyl functionalized polycyclooctenes since no de-esterification is required. Polycondensation of hydrogenated α,ω-dihydroxyl functionalized poly(cyclooctene-co-3-hexylcyclooctene) and succinic anhydride proved to be a convenient way to synthesize high-molecular-weight LLDPE-like polyesters, showing thermomechanical performance comparable with commercially available LLDPE. The presence of only a limited number of ester functionalities and carboxylic chain end groups provides a significantly higher adhesion to aluminum than the LLDPE benchmark.