Effects of synthetic phenolic antioxidants on physical, structural, mechanical and barrier properties of poly lactic acid film

Synthetic phenolic antioxidants (SPAS) including BHA, BHT, PG and TBHQ were added (1%, w/w) to a poly (lactic acid) (PLA) film. SPA addition had no significant effect on the glass transition and melting temperatures of the PLA film but reduced the crystallinity about 26% and the crystallization temperature by 6-12 degrees C from the value of 107 degrees C found for pure PLA film. Young's modulus of PLA film was reduced about 12% by BHA and about 17% by PG and TBHQ. The tensile strength of PLA film also was influenced by BHA, PG and TBHQ. Water vapor permeability of PLA film was not changed by addition of SPAs and PLA oxygen permeability only increased by 30% on BHT addition. No significant changes were observed for surface energy and surface hydrophilicity of PLA films. PLA film microstructures investigated by Atomic force microscopy were significantly changed in term of roughness parameters (R-a and R-q). The results showed that the addition of SPAs in PLA for the creation of active packaging had no negative effect on PLA technical properties. (C) 2011 Elsevier Ltd. All rights reserved.