Poly(Lactic Acid) Films as Food Packaging Materials

摘要

High molecular mass poly(lactic acid), PLA, is an attractive polymer family which has received increased attention in the last decade due to its natural biodegradability. PLA polymers can be totally degraded in aerobic or anaerobic environment in six months to five years. In addition to being biodegradable, PLA is a thermoplastic and compostable polymer produced from annually renewable resources, which can reduce consumption of non-renewable petrochemicals. PLA shows mechanical and barrier behavior comparable to synthetic polymers like polystyrene and polyethylene terephthalate. Properties of PLA such as melting point, mechanical strength, and crystallinity, are determined by the polymer architecture and the molecular mass. PLA can be produced as totally amorphous or up to 40% crystalline. Since new fabrication methods for large-scale fabrication of PLA have lately been developed and patented, PLA is now potentially available for use as a packaging polymer. However, there is still a need to better understand the properties of PLA as this polymer is adapted to packaging applications, especially for food packaging. The aim of this work was to study the mechanical, barrier, and thermal properties of films made from two PLA resins. The experimental values are compared to those of polystyrene and polyethylene terephthalate films.