Thermomechanical Recycling of Polymers via Reversible Dynamic Crosslinking*

Most of the industrially used polymers are immiscible and incompatible and do not form a homogeneous mixture. Stabilizing these immiscible mixed plastics could increase their lifespan and enable previously unrecoverable mixed plastic wastes to be reprocessed and reused. Here, we study how reversible dynamics covalent bonds can reactivate mixed plastic "dead" chains into compatibilized multiblock copolymers. We develop a phenomenological bead-spring model and carry out large-scale hybrid molecular dynamics (MD) – Monte Carlo (MC) simulations of an incompatible homopolymer blend. These simulations show a clear transition from an immiscible blend to a progressively more miscible one via dynamic crosslinking when thermally activated. The creation of a "living" gMBCPs, is found to be the underpinning driver for the increased miscibility. They enhance the local density of microphase-separated domains and compatibilize the interfaces of the blend. The work provides fundamental insights into the thermomechanical recycling of polymers.

Reference:

Clarke et al., Nature 616, 731 (2023)