Incorporating amylopectin in poly(lactic acid) by melt blending using poly(ethylene‐co‐vinyl alcohol) as a thermoplastic carrier. II. Physical properties

This study adds to a previous morphological work (paper I) with further characterization of the developed poly(lactic acid) (PLA) blends containing amylopectin, which made use of an ethylene‐vinyl alcohol copolymer (EVOH) as a melt‐compoundable carrier for the polysaccharide in the biopolyester. The effect of using glycerol as compatibilizer was also characterized. Water and oxygen transport parameters, mechanical properties, and comparative biodegradability tests were evaluated for the blends. From the results, the barrier properties to oxygen were only seen to improve at 0%RH and mostly for the PLA‐EVOH blends, which furthermore showed a positive deviation from the rule of mixtures. At high relative humidity, the blends showed somewhat poorer barrier performance due to the comparatively higher improvement in barrier of the neat PLA at 80% RH. Interestingly, room temperature biodegradability testing suggested that low additions of the blending elements seemed to facilitate the biodegradability of the biopolyester. Despite the fact that properties were not so dramatically improved, incorporating renewable resources within PLA seems as a potentially viable route to reduce PLA supply dependency, retain good optical properties and to overcome some drawbacks associated to the use of this biopolyester.