Control of end-of-life oxygen-containing groups accumulation in biopolyesters through introduction of crosslinked polysaccharide particles

Abstract

The formulation of bio-based materials with good performance in service and controlled end-of-life is imperative for an effective circular economy. In this work, an innovative approach to induce and control the end-of-life of biodegradable polyesters through introduction of crosslinked polysaccharide particles is proposed. Chitosan (Ch) has been subjected to ionotropically crosslinking and then added to polylactic acid (PLA) at different amounts (1.0–4.0%w) by melt mixing. All obtained results suggest that the addition of crosslinked Ch (cCh) particles does not modify significantly the investigated biopolyester properties. Specifically, the thermal analysis of the composites reveals that the addition of unmodified Ch alters the PLA thermal behavior, while the addition of cCh particles does not change the PLA glass transition, cold crystallization and fusion phenomena. The infrared and UV–visible spectroscopic analyses suggest no significant changes in PLA structure. PLA/cCh films show a good optical transparency, which is a desirable property for food packaging applications. In addition, thin PLA-based films have been subjected to UVB exposure and the accumulation of oxygen-containing groups has been monitored in time through spectroscopic analysis. Interestingly, at low exposure time, the presence of chitosan slows down the accumulation of these groups, while at long exposure time, chitosan induces accelerated oxygen-groups formation, supporting its beneficial effect as end-of-life accelerant.