Loading...
Synthesis and characterisation of bioplastic films through valorisation of starch-rich waste from maize (Zea mays) wet-milling
Author(s)
Ross, Magan
Date Issued
2026
Type
master thesis
Publisher
Cape Peninsula University of Technology
Abstract
This thesis presented the synthesis and characterisation of starch-based bioplastic films developed through the valorisation of starch-rich waste derived from the maize wet-milling process. Addressing growing environmental concerns related to conventional petroleumbased plastics, this study explores sustainable alternatives by transforming agro-industrial residues into biodegradable polymer films. Starch, as a renewable and biodegradable polymer, serves as the primary matrix for bioplastic formulation. This research aimed to synthesise starch-based bioplastics for improved performance properties through the addition of filler reinforcements that are rich in lignocellulosic fibre. This research also aimed to address problems of high feedstock costs and the impact on food security through valorising starch and fillers obtained from waste rather than food crops. A comprehensive literature review preceded the experimental work, covering starch production methods, its industrial applications, and bioplastic potential. The experimental methodology involved extracting starch from maize waste collected from a local maize wetmilling facility, followed by the formulation of bioplastic films with varied plasticiser (glycerol), filler (lignin, cellulose-lignin mixture and canola fines), and acetic acid compositions. Mechanical properties, including tensile strength and elongation at break, alongside water absorption behaviour, were assessed. A factorial design model was employed to investigate the effects of five factors, namely starch type (spillage or extract), filler type (cellulose-only or cellulose-lignin mixture), plasticiser mass fraction, filler mass fraction, and acetic acid volume, on key bioplastic properties. Acetic acid was found to have no statistically significant influence on tensile strength, elongation at break, or water absorption and was excluded from further formulations to reduce costs and processing complexity. Spillage starch was identified as the superior raw material, yielding bioplastic films with an optimum tensile strength of 9.7 MPa, elongation at break of 24.9%, and water absorption of 54.2%, outperforming extract starch films in strength and moisture resistance. Subsequently, response surface methodology optimised synthesis conditions for films incorporating canola fines, a lignocellulosic agro-industrial waste. The optimal formulation contained 30% glycerol and 13.5% filler (w/w dry starch), producing films with a tensile strength of 3.3 MPa, elongation at break of 52%, and water absorption of 65%. The incorporation of canola fines improved structural integrity and durability while promoting sustainability by valorising agro-industrial waste, reducing feedstock costs, and aligning with food security goals. This research highlights the critical impact of raw material selection and plasticiser-filler optimisation in developing starch-based bioplastics with desirable mechanical and barrier properties. The elimination of acetic acid simplifies production and decreases costs without sacrificing performance. The findings provide a robust framework for developing costeffective, eco-friendly bioplastics tailored to specific application requirements such as packaging, agricultural films, and single-use products. Future work is recommended to explore lower acetic acid concentrations to fully assess effects influenced by concentration, alongside investigating the long-term durability and environmental biodegradability of these films to confirm commercial viability. Overall, this thesis contributes practical insights and advances the sustainable development of bioplastics derived from agro-industrial waste, supporting the growing bioeconomy and environmental sustainability efforts.
Additional information
Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2026
File(s)![Thumbnail Image]()
Loading...
Name
Ross MN_214050394 (1).pdf
Size
10.19 MB
Format
Adobe PDF
Checksum
(MD5):12b1797646ed332b5203a51e21631e22