Mesoscale modeling of controlled fragmentation of polyolefins

Polyolefins account for more than half of global primary polymers production, however only a small fraction of these polymers are currently being recycled. Controlled fragmentation of chains with the goal of reusing these fragments in subsequent chemical synthesis can offer an alternative recycling approach. We develop a mesoscale framework to model degradation of polyethylene melts at a range of high temperatures. We use the dissipative particle dynamics approach with modified segmental repulsive potential to model random scission in melts of linear chains. We characterize the fragmentation process by tracking the time evolution of the molecular weight distribution of polymer fragments and their dispersity as a function of the degree of conversion. Our results allow one to quantify to what extent the distribution of polymer chain fragments during random scission can be captured by the respective analytical distributions for the range of conversions considered and to predict diffusion coefficients of melts of polymer fragments. Understanding thermal degradation of polyolefins on the mesoscale can result in the development of alternative strategies for recycling a range of thermoplastics.