Wang Chenxu, Boulatov Roman
College of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, Xi'an 710054, China.
Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
Molecules. 2025 Jan 22;30(3):469. doi: 10.3390/molecules30030469.
Mechanical loads degrade polymers by enabling mechanochemical fragmentation of macromolecular backbones. In most polymers, this fragmentation is irreversible, and its accumulation leads to the appearance and propagation of cracks and, ultimately, fracture of the material. Self-healing describes a diverse and loosely defined collection of approaches that aim at reversing this damage. Most reported synthetic self-healing polymers are non-autonomic, i.e., they require the user to input free energy (in the form of heat, irradiation, or reagents) into the damaged material to initiate its repair. Here, we critically discuss emerging chemical approaches to autonomic self-healing that rely on regenerating the density of load-bearing, dissociatively-inert backbone bonds either after the load on a partially damaged material dissipated or continuously and in competition with the mechanochemically driven loss of backbones in the loaded material. We group the reported chemistries into three broad types whose analysis yields a set of criteria against which the potential of a prospective approach to yield practically relevant self-healing polymers can be assessed quantitatively. Our analysis suggests that the direct chain-to-chain addition in mechanically loaded unsaturated polyolefins is the most promising chemical strategy reported to date to achieve autonomic synchronous self-healing of practical significance.
机械载荷通过引发大分子主链的机械化学断裂来降解聚合物。在大多数聚合物中，这种断裂是不可逆的，其积累会导致裂纹的出现和扩展，并最终导致材料断裂。自修复描述了一系列旨在逆转这种损伤的方法，这些方法多样且定义宽泛。大多数已报道的合成自修复聚合物是非自主的，也就是说，它们需要用户向受损材料输入自由能（以热、辐射或试剂的形式）来启动修复。在此，我们批判性地讨论新兴的自主自修复化学方法，这些方法依赖于在部分受损材料上的载荷消散后，或者在与加载材料中机械化学驱动的主链损失竞争的同时持续地再生承载解离惰性主链键的密度。我们将已报道的化学方法分为三大类，对其分析得出了一组标准，据此可以定量评估一种潜在方法生产出具有实际应用价值的自修复聚合物的潜力。我们的分析表明，机械加载的不饱和聚烯烃中的直接链间加成是迄今为止报道的最有前途的化学策略，可实现具有实际意义的自主同步自修复。
