Characterization of EVA/PLA blends when exposed to different environments

EVA/PLA blends compatibilized with EVAg- PLA grafted copolymers synthesized by reactive extrusion, through transesterification reaction between ethylenevinyl- acetate (EVA) and polylactide (PLA) using titanium propoxide (Ti(OPr)4) as catalyst, were characterized when exposed to different environments. Stability to UV radiation was assessed exposing the samples to a Xenon lamp, which simulates the sun UV spectrum and the biodegradability was evaluated by biochemical oxygen demand (BOD) in a closed respirometer. Exposed samples were removed periodically and analyzed by several analytical techniques, such as, FTIR, DSC, rheology and tensile tests. The results obtained evidenced that UV radiation induces structural modifications, which affect substantially rheological and mechanical properties. Moreover, the blend with higher amount of copolymer exhibits lower photo durability and greater biodegradability. From the environmental point of view, these new materials are very promising for application with short lifetime, like packaging.The authors acknowledge the financial support given by FCT through the project PTDC/AMB/73854/2006 and the PhD grant SFRH/BD/29802/2006. FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centre [PEst-C/CTM/LA0025/2011 and PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)]