Effect of polymer blending on mechanical and barrier properties of starch-polyvinyl alcohol based biodegradable composite films

The study was aimed to improve the properties of starch-based biodegradable films by the way of polymer blending. The composite films were prepared by incorporating various proportions of PVA (10, 30, 50, 70, and 90% of starch wt.) to the starch using the solvent casting method. All films were analyzed for their mechanical behavior, barrier properties, water solubility, water contact angle, and biodegradability. Incorporation of PVA to starch polymer significantly (p < 0.05) improved the mechanical and barrier properties of composite films. The highest improvement in mechanical behavior was observed for the SP90 composite film, having a higher content of PVA. SP90 film showed 1.93 fold increase in TS, 3.74 fold increase in E and 1.72 fold increase in BS over the pure starch film. On the other hand, maximum PVA incorporation resulted in 52% and 57% decrease in WVP and OP of composite films respectively, depicting a good barrier against water vapour and oxygen gas. Fourier-transform infrared spectroscopy and scanning electron microscopy of films confirmed the excellent compatibility between starch and PVA polymer. Interestingly, the composite films degraded rapidly in moistened soil within 3 weeks of burial. Biodegradability study showed a promising potential of starch-PVA composite films for the development of eco-friendly food packaging material.