(454a) Upcycling Polyolefin Waste into Performance Elastomers

Recycling represents an important solution to the plastics crisis, it has the potential to substantially reduce waste accumulation while allowing for CO2 reduction by re-use the fossil fuel resources. However, a myriad of challenges, in particular, mixed wastes/multi-plastic parts and dyes and fillers make plastic recycling a problem extremely difficult to solve. Here we developed a new process for polymer upgrading that is based on transforming blends of polyolefins into high performance rubber parts via chemical modification by melt processing. Given our recent studies on the detailed chemistry as well as property predictions for the melt processing of polyolefins, trials to synthesize upcycled rubber from virgin low density, linear low density and high density polyethylene (LDPE, LLDPE, HDPE) are executed as a proper representative of polyethylene (PE) waste. By implementing a melt-modification step with the traditional functionalization and curing, the compatibility among different grades of PE is enhanced while resetting the level of crystallinity via both short chain branching and chain coupling, therefore improves the rubbery behavior at room temperature. With the design of experiments for a thorough understanding on the effects of detailed upcycling formulation along with processing condition on the mechanical properties of upcycled rubbers, our results on LDPE, LLDPE and HDPE pellets show great progress on lowering its original high crystallinity level and the associated yield stress with the proposed upcycling strategy.