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Biodegradable plastic-based items play an essential role in ensuring the sustainability of the food packaging industry due to their high biodegradability and minimized use of fossil fuels. The incorporation of low-cost waste biomass into bio-based polymers to produce biodegradable composites supports the circular economy model and reduces landfilling and carbon footprint challenges associated with petroleum-based plastics. This work discusses the utilization of waste almond shell powder (ASP) up to 50 wt.% with poly(butylene succinate-co-butylene adipate) (PBSA) to develop sustainable biocomposites through injection moulding for rigid packaging applications. At a lower angular frequency (0.1 s − 1), the complex viscosity of the PBSA/50%ASP biocomposite was reduced by ∼65% after adding 5 wt.% compatibilizer, as confirmed by a rheological analysis. The heat deflection temperature, flexural strength, and tensile and flexural moduli of the PBSA/50% ASP biocomposite with 5 wt.% compatibilizer were improved by ∼24, 125, 368, and 385%, respectively, compared to pristine PBSA. These improvements are attributed to the high stiffness and load-bearing capacity of ASP and the enhanced interfacial adhesion and particle dispersion caused by the compatibilizer, as corroborated by SEM analyses. Hence, the formulated biocomposites show a suitable structure-property-processing co-relationship for injection moulding of single-use products.

Abstract Worldwide, improper disposal of plastics is instigating environmental initiatives to combat plastics accumulation of in the environment and the world’s oceans. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biocomposites with Miscanthus (Misc) fibres and distillers’ dried grains with solubles (DDGS) were studied to ascertain if natural fibres and proteinaceous fillers can improve polyhydroxyalkanoate marine biodegradability. Using ASTM standard D7991-15, the biodegradation of PHBV, PHBV with Misc (15 and 25 wt%) and PHBV with DDGS (15 and 25 wt%) was performed in a simulated marine environment for the first time, as indicated by a literature survey. PHBV/Misc (85/15) and (75/25) biocomposites showed 15 and 25% more biodegradation compared to PHBV, respectively. Proteinaceous PHBV/DDGS (85/15) and (75/25) biocomposites showed 17 and 40% more biodegradation compared to PHBV, respectively. Furthermore, PHBV/Misc (75/25) and PHBV/DDGS (75/25) biocomposites were marine biodegraded in 412 and 295 days, respectively. In conclusion, proteinaceous fillers (DDGS) biocomposites have better marine biodegradability than miscanthus.

This research work focuses on the utilization of waste ocean plastics with waste agro-industrial pyrolyzed biomass to develop complex shaped value-added prototypes through additive manufacturing. Fused Filament Fabrication (FFF)-based three-dimensional (3D) printing of recycled HDPE/PP blends was challenging due to significant warpage-related problems during printing. Reinforcing these blend plastics with fillers played a significant role in the efficient 3D printing of complex-shaped objects. In this research, a blend of these recycled HDPE (70%) (rHDPE) and recycled PP (30%) (rPP) collected from the ocean shores was reinforced with pyrolyzed soy hulls-based biocarbon (20%) to fabricate filaments employed for developing specimens through injection molding as well as FFF-based 3D printing. The design of experiments (DOE) using Taguchi method was performed to determine the optimized 3D printing parameters to obtain the defect-free printed specimens. The results suggested that the injection-molded samples showed better mechanical properties as compared with 3D printed samples. However, an improvement (34%) in Young's modulus of the 3D printed rHDPE/rPP (70/30) blend was observed in comparison with injection-molded counterparts. The 3D printed rHDPE/rPP/20% Biocarbon composite showed an improvement of ∼11 and ∼15% in Young modulus and flex modulus, respectively as compared to rHDPE/rPP. Combining ocean plastics and agro-industrial wastes could generate value-added products that would contribute to the circular economy approach for sustainable product development for different applications such as prototyping and automotive, while helping to protect ocean marine life. Two prototypes, elliptical gears with shaft and spectacle frame, have also been developed by using sustainable recycled HDPE/PP-based composites.

Single-use packaging is a major contributor to municipal solid waste and cause of plastic pollution worldwide, whereas the adoption of biodegradable alternatives is still hampered by significant challenges such as performance shortfalls and inadequate barrier properties. The present work utilizes compostable polymers, namely biobased poly(butylene succinate) (BioPBS) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), combined with hybrid natural fillers to achieve enhanced processability and barrier performances for substituting conventional plastic packaging. BioPBS reinforced with 20 wt.% talc showed improved barrier properties over the neat BioPBS, with both the oxygen and water vapor permeabilities improving by about 60%. With the blending of 20 wt.% PHBV, an overall further improvement of about 80% in both properties were achieved. The use of 1% maleic anhydride grafted BioPBS and BioPBS/PHBV-blend coupling agents enhanced the interfacial adhesion of the composites resulting in a consistent improvement of the tensile strength at yield and the oxygen barrier. The incorporation of 5% starch, which could potentially boost the biodegradability of the composites, helped in enhancing the toughness of the material at the expense of lowered barrier properties. Overall, the biocomposites demonstrated comparable mechanical properties to some commodity plastics such as polyolefins while having low oxygen and water permeability, showing great promise for applications in sustainable packaging.