Waste Management Bulletin (Apr 2024)
Influence of 2-hydroxyethyl terephthalate from waste polyethylene plastic on the properties of starch-BHET bioplastics
Abstract
The unabating environmental and human-health impact of synthetic plastics calls for their reduction and reuse. Polyethylene terephthalate bottle is a significant pollutant amongst synthetic plastics, and an effective means of mitigating its environmental pollution menace is recycling and developing environmentally friendly alternatives. The study extracts bis(2-hydroxyethyl) terephthalate (BHET) from discarded polyethylene terephthalate bottles and starch from cassava (Manihot esculenta, Crantz). Composite bioplastic films (SF, SBHETF20, SBHETF40, SBHETF60, and SBHETF80) were produced from the starch with the addition of a varying percentage of BHET. The starch has the following properties, moisture content 6.94 %, protein 1.05 %, amylose 24.94 %, and amylopectin 75.06 %, while fibre and fat are too low to be detected. The extracted starch, BHET, and their produced bioplastics were analysed using FTIR, SEM, TGA/DTGA, DSC, and XRD. The SBHETF80 has the lowest values for moisture content (5.40 %) and opacity (0.34 %) but the highest thickness (0.45 mm) and density (0.27 g/cm3). In comparison, SF has the highest moisture content (6.02 %) and opacity (1.37 %) but the most inferior thickness (0.19 mm) and density (0.13 g/cm3). The characteristic functional groups in starch and BHET were detected in their produced bioplastics. The XRD 2Θ result confirmed the isolation of BHET and revealed the starch as a B-type. The SF (316℃) has the highest Degradation temperature and SBHETF80 has the most elevated Tg(111.63℃). Bioplastic SBHETF40 has the highest tensile strength (2.59 MPa). The study has successfully produced bioplastics with promising properties, especially the tensile strength and moisture content, which are mostly the drawbacks of bioplastics.
