Environmentally Degradable Polymers Incorporating Stimuli‐Triggered Cleavable Linkages toward Industrial Materials

Abstract

Plastics designed to degrade upon exposure to ambient stimuli after use are emerging as promising alternatives to conventional plastics, considering environmental pollution. So‐called “‘biodegradable polymers,”’ which can be degraded by enzymes or microbes, are the most reliable biodegradable polymers, and considerable effort has been devoted to their practical application. Several other examples have also been developed for the cleavage of chemical bonds in macromolecules, as one part of a vast variety of “stimuli‐responsive polymers”, especially for biomedical applications. These chemical insights would provide a design concept that can even be extended to plastic materials. In this review, we outline stimuli‐cleavable linkages, drawing from the chemical insights cultivated in biomedical fields, intended for application in degradable plastics. As stimuli for polymer degradation, pH changes, photo‐irradiation, and redox conditions are selected because polymers released in natural environments may inadvertently be exposed to these stimuli. The degradation pathways are grouped into five categories: 1) stimuli‐cleavable linkages, 2) self‐amplifying, 3) self‐immolative, 4) chain shattering, and 5) double responsive. The classification and organization of the stimuli‐cleavable linkages provide insights for designing new, degradable polymers.This article is protected by copyright. All rights reserved