The Possibility of Using Polylactic Acid and Polyhydroxyalkanoates to Replace the Normal Plastics in Life

traditional plastics such as polypropylene (PP), polyethylene (PE), and car tire rubber (CTR) have been widely used in our lives, leading to significant microplastic pollution, particularly in major river systems in China like the Yangtze River Basin. These plastics possess highly durable and resistant properties that resist natural degradation, resulting in long-term environmental problems and ecological risks. This study investigates the possibility of replacing conventional plastics with biodegradable alternatives, especially polylactic acid (PLA) and polyhydroxyalkanoates (PHA). By comparing their degradation in water, environmental behavior, mechanical properties, and industrial production processes, the paper analyzes the potential of PLA and PHA to reduce microplastic emissions. The results show that although PLA and PHA exhibit superior biodegradability under specific environmental conditions, their thermal resistance and mechanical limitations hinder their full replacement of conventional plastics in demanding applications such as vehicle tires. However, through polymer blending, plasticization, and nanocomposite reinforcement techniques, significant improvements in heat and abrasion resistance can be achieved, pointing toward a future where biodegradable plastics could play a vital role in mitigating microplastic pollution.