(152f) Waste wheat starch-based home compostable plastics for packaging applications

The accumulation of waste plastics and pollution caused by improper disposal are among the most pressing issues threatening the health of ecosystems around the world. While starch is abundant, inexpensive, renewable, and biodegradable, it cannot be used directly as a plastic. This study takes waste wheat flour from the food industry and combines it with a biodegradable plastic to produce bioplastics and composites that are home compostable at the end of their life. After plasticizing the waste starch with glycerol (recovered as a by-product of the bio-diesel industry) to produce plasticized wheat starch (PWS), thermoplastic starches were successfully prepared through with poly(butylene adipate terephthalate) (PBAT) in a 30/70 ratio. Extrusion and injection molding techniques were used to produce test specimens in accordance with ASTM standards. To enhance the mechanical and thermal properties, calcium carbonate (CaCO3) and talc were added as fillers to the thermoplastic starch. The melt flow properties, thermal behaviour, surface functionality, morphology, and dimensional stability at high temperatures were analyzed along with the mechanical properties. PBAT/PWS (70/30) specimens displayed the highest elongation at break values of 208.28%, making the formulation suitable for packaging applications. The addition of CaCO3 resulted in an improved melt flow rate of 27 g/10min while the talc powder had a value of 14 g/10 min. The talc composite showed the highest tensile modulus of ~475 MPa, 134% higher than that of PBAT/PWS (70/30). The waste-starch-based composites show promise as sustainable alternatives to single-use fossil-fuel-based plastics with reduced environmental impact.

Keywords: Plasticized starch, starch bioplastics, starch-based composites.

Acknowledgements: (i) The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) – University of Guelph, the Bioeconomy Industrial Uses Research Program Theme (Project Nos. 030486 and 030578); (ii) OMAFRA-University of Guelph Gryphon’s Leading to the Accelerated Adoption of Innovative Research (LAAIR) Program (Project No. 030416); (iii) the Ontario Research Fund, Research Excellence Program; Round-9 (ORF-RE09) from the Ontario Ministry of Economic Development, Job Creation and Trade, Canada (Project No. 053970); and (iv) the Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Research Chair (CRC) program Project No. 460788.