(24b) Sustainable Biocomposites from Walnut Shell Powder Filled Poly(Butylene Succinate-co-Butylene Adipate) (PBSA)/Poly(Butylene Adipate-co-Terephthalate) (PBAT) Blend

Traditional practices of production and consumption of petroleum-based plastic for packaging applications are becoming obsolete due to the negative implications of non-biodegradable plastics on the environment. The current research investigates the utilization of home compostable polymers with discarded food waste as a feasible and sustainable alternative in packaging applications. PBAT comprises aromatic and aliphatic units, exhibits higher toughness and %elongation at break, making it suitable for various applications. PBSA, derived from polybutylene succinate (PBS), exhibits significant variability for several processing methodologies and good mechanical properties such as flexibility. Walnut shells (WS) are used as a natural filler due to their tough exterior and chemical composition (49.7% polysaccharides, 30.1 % lignin and 10.6% extractives). The previous research has primarily focused on polymer blends with polybutylene adipate terephthalate (PBAT). However, limited research has been performed on polymer blends, including polybutylene succinate-co-adipate (PBSA) and PBAT. This study will investigate the effectiveness of such a blend comprising PBSA:PBAT (60:40) in the presence of waste walnut shells powder (WSP)in a range of 15 – 50 wt%. Incorporating a higher content (up to 50 wt%) of WSP with biopolymers blend through the injection moulding process, a relatively higher heat deflection temperature (HDT), i.e., 79 °C, was observed as compared to PBSA/PBAT blend (53 °C). The tensile and flexural modulus of the PBSA/PBAT blend with WSP was improved up to 608.40±60.80 and 549.80±27.97 MPa as compared to PBSA/PBAT blends. Such improvements in modulus and HDT were observed due to the flakey fibrous structure of WSP. The impact strength of biocomposite was determined as 48.03±1.74 J/m, which is sufficient for rigid packaging applications. Incorporating a compatibilizer in biocomposites can significantly improve the interfacial adhesion between the components, which helps to enhance the mechanical and thermal properties. It is noteworthy that adding high filler content in the polymer blends reduces the overall cost of the final products (e.g., utensils and containers) and increases the valorization of waste agro-based residues in value-added applications.

Acknowledgements: (i) the Ontario Research Fund, Research Excellence Program; Round 9 (ORF-RE09) Ontario Ministry of Economic Development, Job Creation and Trade (Project Nos. 053970 and 054345); (ii) the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)/University of Guelph – Bioeconomy for Industrial Uses Research Program (Project Nos. 030486, 030578 ); (iii) the Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Research Chair (CRC) program Project No. 460788; and (iv) The NSERC Discovery Grants Project No. 401716.