Practice and tactics in the construction of novel degradable plastics at polymer and molecular levels

The convenient and widespread use of plastics has caused a buildup of plastic waste with the slowly degradable physicochemical properties posing serious risks to the environment and human health. To ensure the sustainable use of plastics, it is important to develop advanced mitigation strategies for their controlled degradation. In light of this, this review explores technical options required to induce the efficient degradation of plastics through the manipulation of their composition, especially by focusing on the approaches available at polymer and molecular levels. The feasibility of the polymer-level approach is evaluated through comparative analysis of the utility of various additives (e.g., photocatalysts, pro-oxidants, enzymes, and natural polymers), while that of the molecular-level approach is examined between three key technical options (i.e., olefin metathesis polymerization, mechanochemistry, and reversible covalent chemistry). Although these approaches are employed to help facilitate the design and recycling of degradable plastics, further research is needed to overcome many technical limitations (e.g., accidental degradation, high cost, and low mechanical strength). Future research directions for the production of controlled degradable plastics are also discussed in relation to advanced options such as adoption of data-intensive machine learning, combination of multimolecular techniques, and the ecotoxicology of their degradation products. This review offers a comprehensive overview of technologies needed for the scalable production of degradable plastics and the reduction of their environmental toxicity by exploring solutions at both the polymer and molecular levels.