Degradation of poly(1,3‐dioxolane). Depolymerization versus hydrolysis

Abstract

AbstractThere is renewed interest in polymers of 1,3‐dioxolane (DXL), especially as components of degradable polymer networks. DXL, a five‐membered cyclic acetal, is easily available on a commercial scale. Due to the relatively low strain of the five‐membered ring, its polymerization proceeding by a cationic mechanism is reversible. Above the ceiling temperature in the presence of an acid catalyst, it therefore undergoes depolymerization and this is one of the possible ways of degradation. On the other hand, monomeric units within the poly(1,3‐dioxolane) (PDXL) chain are connected by acetal bonds that are susceptible to acid‐catalyzed hydrolysis and this offers an alternative route for PDXL chain degradation. Polymer networks with connecting PDXL blocks are designed as commodity plastic materials but also as gels intended for biomedical applications. In both applications the possibility of gel disintegration by controlled degradation of connecting PDXL blocks is advantageous. The degradation in the two instances should proceed under different conditions, however. Degradation of commodity plastic material may proceed at higher temperatures in ‘dry’ conditions while biomaterials should degrade at mild physiological temperatures in an aqueous environment. In published papers, the distinction between the two routes of degradation is not always considered. In the present mini‐review, both mechanisms of degradation are presented and the available information on PDXL bloc degradation is critically evaluated. © 2023 Society of Industrial Chemistry.