Degradable polymer composites for circular and sustainable materials engineering

The escalating environmental impact of conventional plastics necessitates the development of sustainable alternatives. This review presents an interdisciplinary analysis of degradable polymer-based composites, highlighting their pivotal role in achieving circular economy and low-carbon goals. Focusing on biodegradable and biobased polymers such as PLA, PHA, PBS, and PCL, the study explores their integration with natural fibers, agro-waste fillers, and nanomaterials to produce high-performance, eco-friendly composites. Design strategies including compatibilization, hybrid reinforcement, and advanced processing methods like extrusion and 3D printing are discussed. Emphasis is placed on the degradation mechanisms, structure–property relationships, and environmental fate under real conditions, including soil, marine, and composting scenarios. These applications range from packaging, biomedical, agricultural, and automotive fields, whose efficacy has been proved via life cycle assessment as well as mechanical, thermal, and dielectric characterization. Collectively, this review provides a critical perspective on structure–property–process relationships in sustainable polymer composites and demonstrates routes towards multifunctional scalable materials that comply with global objectives of carbon neutralization, waste minimization, and resource management.