Additive-Free Multiple Processing of PLA Pre-Consumer Waste: Influence on Mechanical and Thermal Properties

Poly(lactide) (PLA) is the most versatile biopolymer, but it has an unfavorable end-of-life. Biodegradation occurs under strictly defined conditions, and ultimately, it is landfilled, where it behaves like conventional plastics. To completely utilize the potential of PLA, it is necessary to rethink end-of-life scenarios. In this work, the influence of 10 cycles of reprocessing PLA pre-consumer industrial waste on the material's properties was examined. The mechanical milling of the material was followed by injection molding, and after each cycle, mechanical, thermal, chemical, and optical properties were studied. Between the cycles, no virgin PLA or any additives were added to enhance the properties. Results showed a slight decrease in molecular weight, while the thermal properties remained unchanged compared to the starting material.