Super-tough poly(lactic acid) using a fully bio-based polyester containing malic acid via in-situ interfacial compatibilization

Reactive interfacial compatibilization is the most efficient way to prepare super-tough poly (lactic acid) (PLA) materials. Introducing a post-reactive group into a toughening agent that can react with PLA is the key issue. Herein, we reported a series of fully bio-based polyesters (PBSePM) synthesized with sebacic acid, diethyl malate, 1,3-propanediol, and 1,4-butanediol via transesterification in one pot. Super-tough PLA materials can be obtained by reactively blending with PBSePM in the presence of hexamethylene diisocyanate (HDI). In the processing, the side hydroxyl group of the PBSePM reacted with HDI and formed polyurethane elastomer to improve the toughness of PLA. Moreover, the in-situ formed PLA-g-PBSePM grafted copolymer enhanced the interfacial adhesion. With increasing diethyl malate moiety in PBSePM, the PBSePM phase morphology transformed from co-continuous phase structure to semi-continuous and sea-island phase structure. When adding 20 wt% PBSePM, all PLA/PBSePM blends have a notched impact strength higher than 53 kJ m(-2), suggested a super toughness effect. Maximum impact strength of 83 kJ m(-2) was realized while the PBSePM containing 20% diethyl malate moiety. In addition, super-tough PLA materials can be achieved by only adding 15 wt% PBSePM20, exhibited a highly efficient toughening effect.

Automated summary

Reactive interfacial compatibilization is found to be an effective method for preparing super-tough poly (lactic acid) (PLA) materials through introducing a reactive group into toughening agents that can react with PLA. Super-tough PLA materials can be obtained by reactively blending with a series of fully bio-based polyesters (PBSePM) and hexamethylene diisocyanate (HDI). The maximum impact strength of 83 kJ m(-2) is achieved with PBSePM containing 20% diethyl malate moiety, demonstrating a highly efficient toughening effect with the addition of only 15 wt% PBSePM20.