Effect of different fillers on the biodegradation rate of thermoplastic starch in water and soil environments

Abstract

This work investigates the effect of filler type on the rate of biodegradation of thermoplastic starch-based films in water and soil environments. The authors applied the casting method to create films of thermoplastic starch, based on waste paper, filled with clays or organic fillers. Since such materials made from cellulose tend to absorb water, we hydrophobized the surfaces of the filled thermoplastic starch samples. The structures of the blends were characterized by infrared spectroscopy, while atomic-force microscopy was applied to observe change in surface topography and the distribution of the filler. We also studied moisture resistance of the blends. Biodegradation tests revealed that surface topography, distribution of the filler and starch-to-filler interactions were non-critical to the rate and degree of biodegradation of the blends. The biodegradation rate of the blends was strongly affected by the environmental conditions (relative humidity 54%, 100%, respectively; temperature 25 °C, 37 °C, respectively). Under anaerobic conditions, it was the mixtures that biodegraded to the greatest extent, whereas the hydrophobized mixtures did so the least. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.