892: MULTIPLE RECYCLING OF PLA WITH TAILOR-MADE MULTIFUNCTIONAL REACTIVE POLYMER ADDITIVES

MULTIPLE RECYCLING OF PLA WITH TAILOR-MADE MULTIFUNCTIONAL REACTIVE POLYMER ADDITIVES

M. Szewczyk-Łagodzińska^a, L. Dziugieł^a, S. Kowalczyk^a, N. Grochowska^a, A. Plichta^a

^a Warsaw University of Technology,

Faculty of Chemistry, Noakowskiego 3 street, 00-664 Warsaw, Poland

(matylda.lagodzinska.dokt@pw.edu.pl)

Poly(lactic acid)’s (PLA) life cycle assessment revealed that mechanical recycling of PLA waste has the lowest environmental impact among PLA waste treatment methods, including chemical recycling and composting.¹ Mechanical recycling is also cost-friendly. However, the efficiency of this method is jeopardized by polymer degradation (hydrolytic and thermo-oxidative via radicals), occurring at elevated temperatures necessary for polymer processing.

Different multifunctional additives for PLA recycling were synthesized utilizing Activator ReGenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP) and then refunctionalized, so that the final products could act as chain extenders, antioxidants, and mechanical properties enhancers.^2,3 PLA-additive blends were mixed inside a laboratory extruder for 30 min to mimic mechanical recycling. The extent of polymer degradation during and after each cycle was analyzed by observing the viscosity loss and molecular weight change (with gel permeation chromatography). Furthermore, extruded materials were subjected to impact and tensile strength tests. Finally, the antioxidant properties of the additives were checked with a UV-aging test as well.

To verify the efficiency of the best-performing additive for PLA recycling, the additive was synthesized on such a scale to allow for the PLA-additive blend extrusion on an industry-sized machinery. The synthesis pathway included ARGET ATRP and then functionalization of epoxide groups with 3 different specialty molecules in a one-pot reaction.

The research was funded by POB Technologie Materiałowe of Warsaw University of Technology within the Excellence Initiative: Research University (IDUB) program.

(1)    Cosate de Andrade, M. F.; Souza, P. M. S.; Cavalett, O.; Morales, A. R. Life Cycle Assessment of Poly(Lactic Acid) (PLA): Comparison Between Chemical Recycling, Mechanical Recycling and Composting. J Polym Environ 2016, 24 (4), 372–384. https://doi.org/10.1007/s10924-016-0787-2.

(2)    Plichta, A.; Jaskulski, T.; Lisowska, P.; Macios, K.; Kundys, A. Elastic Polyesters Improved by ATRP as Reactive Epoxy-Modifiers of PLA. Polymer 2015, 72, 307–316. https://doi.org/10.1016/j.polymer.2015.03.055.

(3)    Szewczyk-Łagodzińska, M.; Oleksiuk, D.; Kowalczyk, S.; Czajka, A.; Dużyńska, A.; Łapińska, A.; Ryszkowska, J.; Dziewit, P.; Janiszewski, J.; Plichta, A. Multifunctional Block Copolymers, Acting as Recycling Aids, by Atom Transfer Radical Polymerization. ChemSusChem 2024, 17 (6), e202301232. https://doi.org/10.1002/cssc.202301232.