Synthesis of Cleavable Polyolefins via Ring-Opening Insertion Metathesis Polymerization (ROIMP) of Cyclopentene with Unsaturated Polyester Oligomers

The replacement of persistent plastics with chemically recyclable and environmentally benign alternatives is an urgent environmental challenge. Although an increasing number of degradable polymers are now available, many face limitations that prevent their efficient direct substitution for durable plastics, such as polyethylene. Here, we present a methodology for the synthesis of polyolefin copolymers containing cleavable units via Ring-Opening Insertion Metathesis Polymerization (ROIMP) of cyclopentene (<b>CP</b>) with unsaturated polyester and polycarbonate oligomers. In the first step, diallyl ester oligomers were prepared through acyclic diene metathesis (ADMET) polymerization followed by copolymerization with <b>CP</b> via ROIMP to yield long-chain polypentenamer (<b>PPe</b>) dyads separated by singular, easily cleavable ester or carbonate functionalities. Hydrolysis of the resulting cleavable <b>PPe</b> elastomers produced low-molecular-weight, telechelic OH-end-functionalized <b>PPe</b> oligomers. Subsequent hydrogenation using Wilkinson's catalyst afforded saturated long-chain hydrocarbon polymers with randomly distributed cleavable subunits. The scalability of this approach was demonstrated for the ROIMP of <b>CP</b> with oligo-diallyl succinate (<i>oligo</i>-<b>DAS</b>).