Degradable Plastics and Their Composites: A Comprehensive Review of Production, Properties, and Applications

Degradable plastics constitute a category of polymeric materials that degrade via biological, chemical, photochemical, or physical processes, with environmental outcomes dependent on the degradation endpoint and disposal conditions. This paper examines the scientific principles, degradation mechanisms, classification, and production processes of these materials, with a focus on poly(lactide) (PLA) and polyhydroxyalkanoates (PHAs). It provides a detailed account of both natural and synthetic raw materials employed in production, polymerization technologies, and methods for forming and shaping products. Particular attention is given to composites with natural and synthetic fibers, their mechanical and thermal properties, and techniques for modifying functional properties. Applications in the packaging, medical, and automotive industries are analyzed, emphasizing the significance of biodegradability and compliance with environmental standards. The life cycle of products, recycling and reuse methods, as well as future research directions, including the utilization of novel biomass raw materials, innovative production technologies, and controlled degradation design, are discussed. To realize the environmental benefits of degradable plastics, it is essential to align their service performance with confirmed degradation processes and viable end-of-life management strategies. Consequently, there is a focus on the examination of residual intermediates and particles, disposal behaviors, and the constraints associated with compostability claims.