Performance of Food Packaging based on Poly (Lactic Acid)/Clay Nanocomposites During Natural Weathering: Mechanisms and Characteristics

Poly lactic acid (PLA)Nan composite has various applications in food packaging due to their biodegradable character. However, application of PLA Nan composite is somewhat limited by its limited range of physical properties such as thermal stability and gas barrier properties and its brittle nature. Dispersion of the Nan clay in the polymer matrix can provide remarkable improvement of PLA Nan composites properties. In this study, involved mechanisms in natural weathering and its effect on changing the properties of PLA Nan composites during storage have been investigated. Chemical degradation of polymers is a very important process and irreversible, which affects the performance of all plastic materials in packaging life and leads finally to the loss of its protectively. Natural weathering (or outdoor weathering) have been used extensively In order to assess the durability of food packaging polymers. The destruction process of Oxidative photo degradation phenomenon or photo oxidation of packaging Nan composites depends on several factors, and the most important factor would be the sunlight that is responsible for the initial or primer of photo process in polymer degradation. The nature of the main oxidation products of packaging Nan composite is now is well known although the mechanisms by which oxidation occurs are somewhat controversial. Studies showed that physicochemical and fuctional properties of PLA and clay PLA/Cloisite 30B Nan composites change during maintenance. Also, a combination of low molecular weight has been created in polymers, and this change was increased with increase in clay loadings. Crystallinity parameter increases during maintenance. Glass transition temperature (Tg) decreased and this property decreases with increasing clay content. Loss of mechanical response as a result of polymer optical deterioration is evident. Accordingly, it was reported that most of the tensile properties of PLA films were affected by UV irradiation. The interring of clay fillers in the PLA Nan composites in addition to improving the physical properties of the resulting film (fragility, barrerly of gaseous and so on), could be theirs degradability to lower than six months that a major problem in the context of synthetic polymers for food packaging.