Physico-Chemical, Mechanical and Morphological Properties of Biodegradable Films Based on Arrowroot Starch and Poly(vinyl alcohol)

Biodegradable polymeric blends have been widely studied due to their potential of reducing pollution caused by non-biodegradable materials. The research described here describes a polymer blend that benefits both from the abundance of arrowroot starch (AS) and the good mechanical properties of poly(vinyl alcohol) (PVA). Glycerol (GLY) was used in different proportions as a plasticizer. The addition of GLY improved the mechanical properties of the blends, increasing the elongation at break up to 667%. On the other hand, the GLY addition adversely affected other properties, increasing the water vapor permeability (WVP), solubility and hydrophilic characteristics and reducing the thermal stability and the crystallinity index. The AS/PVA blend without GLY addition showed better physical-chemical properties, having strong chemical interaction between the two kinds of polymeric chains (according FTIR analysis) and a homogeneous morphology (SEM morphological analysis). In general, decreasing the AS content improved the mechanical and WVP properties, the film becoming less hydrophilic. In conclusion, the AS/PVA blends cast films, with or without GLY, are biodegradable materials suitable for packaging applications.

Automated summary

The study found that the addition of glycerol can improve the mechanical properties of the polymer blend, but at the same time has adverse effects on other properties. Blends without glycerol showed better physical-chemical properties.