Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA; email:
Annu Rev Chem Biomol Eng. 2020 Jun 7;11:183-201. doi: 10.1146/annurev-chembioeng-120919-012253. Epub 2020 Apr 6.
The production of thermoset polymers is increasing globally owing to their advantageous properties, particularly when applied as composite materials. Though these materials are traditionally used in more durable, longer-lasting applications, ultimately, they become waste at the end of their usable lifetimes. Current recycling practices are not applicable to traditional thermoset waste, owing to their network structures and lack of processability. Recently, researchers have been developing thermoset polymers with the right functionalities to be chemically degraded under relatively benign conditions postuse, providing a route to future management of thermoset waste. This review presents thermosets containing hydrolytically or solvolytically cleavable bonds, such as esters and acetals. Hydrolysis and solvolysis mechanisms are discussed, and various factors that influence the degradation rates are examined. Degradable thermosets with impressive mechanical, thermal, and adhesion behavior are discussed, illustrating that the design of material end-of-life need not limit material performance.
热固性聚合物因其具有优势特性而在全球范围内的产量不断增加，尤其是将其用作复合材料时。尽管这些材料传统上用于更耐用、更持久的应用，但最终在其可用寿命结束时它们会变成废物。由于传统热固性废物的网络结构和加工性能不足，目前的回收利用方法并不适用于它们。最近，研究人员一直在开发具有适当功能的热固性聚合物，以便在使用后在相对温和的条件下进行化学降解，为未来热固性废物的管理提供了一条途径。本文综述了含有可水解或可缩醛解键的热固性聚合物，例如酯和缩醛。讨论了水解和缩醛解机理，并研究了影响降解速率的各种因素。本文还讨论了具有令人印象深刻的机械、热和粘附性能的可降解热固性聚合物，这表明材料设计的使用寿命结束不必限制材料性能。
