Influence of carboxytelechelic oligomer molecular weight on the properties of chain extended polyethylenes

Abstract

Chain-transfer ring-opening metathesis polymerization (CT-ROMP) previously provided a route to carboxytelechelic polyethylene (PE) of controlled molecular weight; however, the incorporation of oligomeric PE into chain-extended copolymers remains relatively unexplored. Herein, CT-ROMP afforded carboxytelechelic polycyclooctene oligomers of varying molecular weight, and subsequent reduction generated a series of well-defined carboxytelechelic PEs. Melt polycondensation of the telechelic PE oligomers with either 1,6-hexanediamine or 1,6-hexanediol chain extenders generated diester and diamide linked PEs to further understand the influence of linkage structure. The thermomechanical and tensile properties of the step-growth polymers exhibited remarkably similar performance to conventional HDPE independent of PE oligomer molecular weight. The chain extended PEs displayed advantageous physical properties while introducing susceptibility to chemolytic depolymerization, tunable via periodic ester or amide linkages, thus providing valuable fundamental understanding of an alternative route to degradable HDPE. • Chain-transfer ROMP facilitated the synthesis of carboxytelechelic polyethylene of varying molecular weights. • Telechelic PE oligomers underwent chain extension with either a diol or diamine via melt polycondensation. • Chain-extended PEs displayed comparable thermal and mechanical performance to commercial HDPE, while remaining degradable at reactive linkages.