Polylactide, thanks to its properties, is gaining more and more interest in the plastics industry. One of its advantages is biodegradability, which allows for the environment-friendly management of PLA waste [1]. However, the long time of the process and the need to provide appropriate conditions make mechanical recycling a better solution. Unfortunately, repeated processing of PLA due to shear forces, high temperatures, and moisture leads to the destruction of polymer chains, resulting in the deterioration of processing and mechanical properties of material [2].
This work presents multifunctional reactive additives for polyester recycling, using PLA as a model polymer. The synthesis of additives began with the Activator ReGenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP), obtaining a copolymer composed of a certain number of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) units. After polymerization, some of the epoxy groups were opened with functionalized poly(ethylene glycol) (mPEG), primary and secondary antioxidants. During the reactive extruding, the epoxy groups from GMA react with the terminal carboxyl and hydroxyl groups of the PLA. During recycling, an increase in viscosity and improvement of mechanical properties were observed. Moreover, the incorporation of mPEG into the additive chain improved its miscibility with PLA. The optimal amount of additive giving the best performance was selected. The results were compared with the data obtained for similar triblock copolymer additives synthesized using flexible macroinitiators [3, 4].
The research was funded by POB Technologie Materiałowe of Warsaw University of Technology within the Excellence Initiative: Research University (IDUB) program.