Recycling PLA to multifunctional oligomeric compatibilizers for PLA/starch composites

Simple one-pot valorization of poly(lactic acid) (PLA) to green additives was demonstrated. PLA was thermally recycled in the presence of polyols, which accelerated the degradation process by reacting with PLA chains. As a result low molecular weight oligomers with polyols end-groups were formed. The reaction between PLA and multifunctional alcohols i.e. glycerol, sorbitol, glucose and starch were confirmed by FTIR, H-1 NMR, SEC and MALDI-MS. The resulting amphiphilic products were evaluated as compatibilizer candidates for PLA/starch blends. Multiple techniques demonstrated that the obtained oligomers strengthened the interfacial adhesion and improved the compatibility and flexibility of extruded and melt-blended PLA/starch composites. The developed one-pot procedure required no solvent or catalyst offering good possibilities for up-scaling. It was, thus, demonstrated that PLA can be recycled to low molecular weight compatibilizers by simple process of thermal heating in the presence of polyols. This provides profound promise for retaining the material value of old PLA products at the same time as biobased additives are produced. (C) 2015 Elsevier Ltd. All rights reserved.