Yan Tianwei, Balzer Alex H, Herbert Katie M, Epps Thomas H, Korley LaShanda T J
Department of Chemical & Biomolecular Engineering, University of Delaware Newark 19716 Delaware USA
Center for Plastics Innovation (CPI), University of Delaware Newark 19716 Delaware USA
Chem Sci. 2023 May 5;14(20):5243-5265. doi: 10.1039/d3sc00551h. eCollection 2023 May 24.
The circularity of current and future polymeric materials is a major focus of fundamental and applied research, as undesirable end-of-life outcomes and waste accumulation are global problems that impact our society. The recycling or repurposing of thermoplastics and thermosets is an attractive solution to these issues, yet both options are encumbered by poor property retention upon reuse, along with heterogeneities in common waste streams that limit property optimization. Dynamic covalent chemistry, when applied to polymeric materials, enables the targeted design of reversible bonds that can be tailored to specific reprocessing conditions to help address conventional recycling challenges. In this review, we highlight the key features of several dynamic covalent chemistries that can promote closed-loop recyclability and we discuss recent synthetic progress towards incorporating these chemistries into new polymers and existing commodity plastics. Next, we outline how dynamic covalent bonds and polymer network structure influence thermomechanical properties related to application and recyclability, with a focus on predictive physical models that describe network rearrangement. Finally, we examine the potential economic and environmental impacts of dynamic covalent polymeric materials in closed-loop processing using elements derived from techno-economic analysis and life-cycle assessment, including minimum selling prices and greenhouse gas emissions. Throughout each section, we discuss interdisciplinary obstacles that hinder the widespread adoption of dynamic polymers and present opportunities and new directions toward the realization of circularity in polymeric materials.
当前和未来高分子材料的循环利用是基础研究和应用研究的主要焦点，因为不良的使用寿命结束结果和废物积累是影响我们社会的全球性问题。热塑性塑料和热固性塑料的回收或再利用是解决这些问题的一个有吸引力的方案，然而这两种选择都存在再利用时性能保留不佳的问题，以及常见废物流中的异质性限制了性能优化。将动态共价化学应用于高分子材料时，能够有针对性地设计可逆键，这些可逆键可根据特定的再加工条件进行定制，以帮助应对传统回收利用的挑战。在这篇综述中，我们强调了几种能够促进闭环可回收性的动态共价化学的关键特征，并讨论了将这些化学方法纳入新型聚合物和现有通用塑料的最新合成进展。接下来，我们概述了动态共价键和聚合物网络结构如何影响与应用和可回收性相关的热机械性能，重点关注描述网络重排的预测物理模型。最后，我们使用技术经济分析和生命周期评估得出的要素，研究了动态共价高分子材料在闭环加工中的潜在经济和环境影响，包括最低销售价格和温室气体排放。在每一部分中，我们都讨论了阻碍动态聚合物广泛应用的跨学科障碍，并提出了实现高分子材料循环利用的机遇和新方向。
