A Comonomer Strategy for Triggered Degradation and Re/Upcycling of High-Performance Thermoset Plastics

Thermosets play a key role in the modern plastics and rubber industries, comprising ~18% of polymeric materials with a worldwide annual production of 65 million tons. The high density of crosslinks that give these materials their useful properties comes at the expense of facile degradability and re/upcyclability. Here, using the high-performance industrial thermoset plastic poly-dicyclopentadiene (pDCPD) as a model system, we show that when a small number of cleavable bonds are selectively installed within the strands of thermoset plastics using a low-cost comonomer approach, the resulting materials display the same exceptional properties as the native material yet they can undergo triggered degradation to yield soluble, re/upcyclable products of controlled size and functionality. In contrast, installation of cleavable crosslinks, even at comparably high loadings, does not produce degradable materials. These findings shed new light on the topology of polymer networks, revealing cleavable bond location as a universal design principle for controlled thermoset degradation and re/upcycling.