Biopolymer Dispersed Poly Lactic Acid Composites and Blends for Food Packaging Applications

Abstract

Packaging is a vital part of any commodity. A wide variety of containers have been manufactured as per the need or type of product to be packed. Synthetic polymers from petroleum sources are popular due to their superior physical properties and durability. However, synthetic polymers increase the carbon emission in the atmosphere during the production process which is detrimental to the ozone layer. A major portion of the synthetic polymers are not biodegradable and end up in landfills or in the oceans. They are now considered a menace to the environment and living resources if not disposed of properly. Biopolymers are derived from natural sources like plant or animals. Different packaging applications using biopolymers are being researched upon. The advantages of biopolymers are that during their degradation in the soil the carbon dioxide released is reabsorbed by the plants and this reduces the carbon levels in the atmosphere. Polylactic acid (PLA) is a thermoplastic biopolymer derived from corn, sugarcane or cassava and has end-use application in food, medical, automobile, and printing industry. PLA is modified suitably based on the application by crosslinking or synthesizing with other polymers or by incorporating different fillers from natural origin. PLA has been blended with different types of clays, cellulose nanocrystal, thermoplastic starch, chitosan, etc. to enhance its properties. The fillers have either a negative or positive effect on the films physical property. The levels of incorporation are varied depending on the compatibility. The film characteristics generally include thickness, heat seal, tensile strength and elongation at break, film barrier properties such as water vapour and oxygen transmission rate, etc. The overall migration of the films are also needed to determine to check its suitability for food contact applications. FTIR spectroscopy and surface characteristics were determined by using a scanning electron microscope. For evaluating the films for food packaging, different PLA films have been used for packing of fish/prawns during chilled storage. The shelf life of the fish/prawns is determined based on microbiological and biochemical evaluations and end point limits. The antimicrobial properties of the films are also estimated against specific microorganisms. Various studies have found that PLA films are suitable for packaging of food products at various conditions.