Preparation and Characteriztion of Biodegradable Composite Films from Poly (vinyl alcohol) and Natural Proteins for Food and other Packaging Applications

Abstract

Packaging materials provide a means to preserve, protect, merchandise, market and distribute foods. Synthetic polymers are widely and massively used to make packaging materials for diverse applications.The environmental issues due to the non-degradability of the polymer packaging material wastes demands biodegradable and environmental friendly polymers for these applications. Hence increasing research is focussed to manufacture packaging materials from biodegr-adeable synthetic and natural polymers.The present study involves fabrication of biodegradable composite polymer films by solution casting from natural biopolymers such as whey and soy proteins, and synthetic biocompatible polymer such as poly(vinyl alcohol) using UV light, glutaraldehyde etc as croslinkers, and glycerol as a plasticizes. The prepared films were evaluated for their tensile strength, water vapour permeability, thermal stability, biodegradability, structure, morphology etc. The tensile strength in terms of breaking load and % elongation measured on non standard dimension of the films were in the range 1.6 -4.7 kgf and 75-400 % respectively. Thermogravimetric studies indicated that polymer films were sufficiently thermostable for packaging uses. Soil burial test and X-ray diffraction studies of the films indicated that they were biodegradable and predominantly amorphous respectively. Glutaraldehyde crosslinked composite polymer films were found to have improved antimicrobial properties compared to the uncrosslinked film. The water vapour permeability of the fabricated films were within the acceptable range of values (5.208 -7.81 g/cm2h * 10-5 ) reported for typical biopolymer films used in packaging applications. The fabricated composite polymer films may be exploited for commercial packaging applications.