A Basic Characterisation Study of Bioplastics via Gelatinization of Corn Starch

Abstract

Plastic waste is the third-largest waste source in the world, so it raises the world’s human health and environmental concerns. Replacing conventional petroleum plastic with bioplastic is an alternative way to minimise plastic wastes from human life and bioplastic is more environmentally friendly. Therefore, this research study aims to synthesise bioplastic from corn starch via gelatinization and study its characteristics. Different from other studies, in this study, new formulations of bioplastics with different ratios of corn starch to glycerol samples that are 1:0.5, 1:1, 2:1, and 2:2, namely Sets A, B, C, and D, respectively, were studied and compared. From the Fourier Transformation Infrared Spectroscopy analysis, the results show that all produced corn starch-based bioplastic samples had the four major plastic’s functional groups which indicated that they were categorized as polyester. Meanwhile, via thermal property analysis, all bioplastic samples could be thermally decomposed from 34 °C to 504 °C where their weight was reduced from 5 mg to 1 mg. Among the four bioplastic samples (Sets A to D) with different ratios of corn starch to glycerol, it was found that a ratio of corn starch and glycerol that was 1:0.5 (Set A) had more biodegradable characteristics and it had the lowest water holding capacity. From the results, Set A could only hold around 4.27 % of the water that could avoid interaction of water with the contents that were wrapped with. Besides, from the results, Set A could degrade better in soils, and dissolve more in ethanol, acetone, and oils when compared to other samples. Since the bioplastic can degrade naturally by the ethanol produced from bacteria in the soils under anaerobic reactions, thus Set A has the potential application to be used as a fertiliser coating to minimise the fertiliser release rate in regions under heavy rainfall.