PhD Research Project in Polymer Chemistry on bio-based PLA additives for packaging application

Poly(lactic acid) (PLA) is one of the leading and most mature bio-based plastics with a global capacity of over 300 000 metric tons per year. PLA is a compostable aliphatic polyester which is produced industrially from lactic acid (more precisely lactide), a building block obtained by fermentation of starchy materials.

The current acceptable price of PLA makes it a serious candidate for a large range of applications thanks to its compostability and its technical substitution potential. Indeed, PLA components are susceptible to partially replace some petroleum-based thermoplastics such as PET, PS... PLA is becoming an economically viable polymer for packaging applications. PLA is mostly used as a food packaging polymer for short life products such as fruit and vegetable, as containers, drinking cups, salad cups, overwrap and lamination films, and blister packages. Commercially available PLA films and packages provide comparable properties to those of PET while better properties compared to PS.

Nevertheless, the inherent brittleness of PLA hinders its use considerably in such applications thus limiting its technical substitution potential. Similarly to polystyrene, PLA was the subject of numerous investigations these past few years, to improve its impact strength. Most of the commercially available impact modifiers are however of petroleum source and nonbiodegradable thus impeding the fully compostable characteristic of the resulting PLA material. Similarly, gas barrier properties of PLA need to be improved for long conservation food packaging application.

This thesis work was financially supported by the New Aquitaine Region  (ADEME) and two technical centers ITERG and CTCPA. The aim of this thesis is to develop several routes to fully bio-based and potentially biodegradable toughened PLA materials with or without enhanced gas barrier properties. More precisely bio-based polymers from vegetable oil will be synthesized and investigated as additives of PLA.

Location : LCPO, Bordeaux, France

Duration : 36 months