Journal of Applied Science & Process Engineering
Vol. 8, No. 2, 2021
* Corresponding author. Tel.: +60 85 630 100 (GMT +8) Ext: 2471; fax: +60 85 630 088
E-mail address: christineyeo@curtin.edu.my
Manuscript History: Received 23 May, 2021, Revised 13 July, 2021, Accepted 15 July, 2021, Published 31 October, 2021
Copyright © 2021 UNIMAS Publisher. This is an open access article under the CC BY-NC-SA 4.0 license.
https://doi.org/10.33736/jaspe.3445.2021
e-ISSN: 2289-7771
820
A Basic Characterisation Study of Bioplastics via Gelatinization of Corn
Starch
Cindy Li Yin Lee, Wan Sieng Yeo*
Department of Chemical Engineering, Curtin University, Malaysia, CDT 250, Miri 98009,
Sarawak, Malaysia
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 cornstarch-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 the ratio of corn
starch and glycerol 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 the interaction of water with the contents that were wrapped. 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.
Keywords: Bioplastic, glycerol, corn starch, gelatinization, fertiliser coating.
1. Introduction
In the past 60 years, human beings had generated 8 billion tons of petroleum-based plastic
globally, and the production rate of plastic is still increasing [1]. Some popular materials are
commonly used to manufacture plastic, including polyethylene, polyvinyl, and polystyrene [2]. Plastic
applications include medical applications, food packaging, toys, containers, mobile items, sports
items, etc. [3]. However, improper plastic waste management and inappropriate human behaviour lead
to the accumulation of an abundance of plastic waste [14]. Most petroleum-based plastics are long-
established plastics that are less sustainable as compared to bio-based plastics [5] and they are difficult