Recent advances in biodegradable polymer blends and their biocomposites: a comprehensive review

Abstract

The growing environmental concerns over plastic pollution and sustainability have led to increased interest in biodegradable polymers as alternatives to conventional plastics. This concern has led to the United Nations resolution of March 2022 calling for urgent action to eradicate plastic pollution globally by 2040 as more than 90% of the global plastic production from 2018 to 2022 was fossil-based, significantly contributing to plastic pollution. In response, there has been a growing shift towards sustainable materials, with biodegradable polymers emerging as a critical solution to mitigate the environmental impacts. However, the properties of biodegradable polymers are at variance with conventional fossil-based plastics in many applications. One way to solve this problem is to re-engineer their properties through polymer blending, a strategy that combines the properties of two or more polymers, aided by compatibilization to improve polymer miscibility and properties. While numerous reviews have focused on biodegradable polymer blends, this article offers a unique contribution by comprehensively examining both biodegradable polymer blends and their reinforced biocomposites within a single review, an area that has seen limited coverage in recent years. This review discusses recent advancements in biodegradable polymer blends and reinforced biocomposites, focusing on material properties, compatibilization techniques, and environmental impact. Key biodegradable polymer blends and reinforced biocomposites based on polylactic acid (PLA), polyhydroxyalkanoates (PHAs), polybutylene succinate (PBS), Polybutylene adipate terephthalate (PBAT), and thermoplastic starch (TPS) are discussed, with a focus on miscibility, compatibilization and the effects on properties. It was found that compatibilizers such as maleic anhydride, dicumyl peroxide, and Joncryl play significant roles in polymer blend miscibility kinetics and compatibility while fillers such as turmeric, cinnamon, coffee ground powder, and rice straw have contributed to improving the mechanical properties and biodegradability of composites. This combined approach of blending and filler reinforcement represents a critical innovation for producing high-performance biodegradable materials. The review examines applications in packaging, agriculture, and biomedical fields, along with the environmental impacts of these materials, such as their biodegradation pathways and ecotoxicity. Lastly, the review discusses future outlooks, including potential breakthroughs and integrating biodegradable polymers into the circular economy.