Effect of Biobased Glycerol Trilevulinate on the Crystallization Kinetics of Biodegradable Polyesters

We study the effect of biobased glycerol trilevulinate (GT) on the nucleation and crystallization of poly(epsilon-caprolactone) (PCL), poly(lactic acid) (PLA), and poly(3-hydroxybutyrate) (PHB). Adding GT to PLA and PHB enhanced their flexibility, decreasing their glass transition (T g), crystallization, and melting temperatures. GT behaved as a plasticizer for PLA and PHB and, conversely, as an antiplasticizer for PCL. As expected, GT addition caused an increase in the crystallization rate of PLA and a decrease in PCL. However, in the case of PHB, there was an unexpected reduction in the crystallization rate with GT addition. The results were explained by a competition between plasticization and exclusion of GT from the crystal front. Conformational and structural FT-IR investigations showed intermolecular interactions between GT and PLA but minimal interactions with PCL and PHB. These findings highlight GT's versatile role in modifying the crystallization of biodegradable polyesters, promoting its potential as a sustainable alternative to petroleum-based additives.