Authors: Cécile Courgneau Sandra Domenek Alain Guinault Luc Avérous Violette Ducruet
Publish Date: 2011/02/22
Volume: 19, Issue: 2, Pages: 362-371
Abstract
Polylactic acid is one of the most promising biobased and biodegradable polymers for food packaging an application which requires good mechanical and barrier properties In order to improve the mechanical properties in particular the flexibility PLA plasticization is required However plasticization induces generally a decrease in the barrier properties Acetyl tributyl citrate ATBC and polyethylene glycol 300 PEG highly recommended as plasticizers for PLA were added up to 17 wt in PDLLA In the case of PEG a phase separation was observed for plasticizer contents higher than 5 wt Contrary to PEG the Tg decrease due to ATBC addition modelled with Fox’s law and the absence of phase separation up to 17 wt of plasticizer confirm the miscibility of PLA and ATBC Contents equal or higher than 13 wt of ATBC yielded a substantial improvement of the elongation at break becoming higher than 300 The effect of PLA plasticization on the barrier properties was assessed by different molecules with increasing interaction with the formulated material such as helium an inert gas and oxygen and water vapour In comparison to the neat sample barrier properties against helium were maintained when PLA was plasticized with up to 17 wt of ATBC The oxygen permeability coefficient and the water vapour transmission rate doubled for mixtures with 17 wt ATBC in PLA but increased fivefold in the PEG plasticized samples This result is most likely caused by increased solubility of oxygen and water in the PEG phase due to their mutual miscibility To conclude ATBC increases efficiently the elongation at break of PLA while maintaining the permeability coefficient of helium and keeping the barrier properties against oxygen and water vapour in the same order of magnitude
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