School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composite Materials, and Shanghai Key Lab of Electrical Insulation & Thermal Ageing, Shanghai Jiao Tong University , Shanghai 200240, P. R. China.
ACS Appl Mater Interfaces. 2017 Aug 16;9(32):27213-27222. doi: 10.1021/acsami.7b06407. Epub 2017 Aug 7.
Pristine carbon nanotubes (CNTs) were activated to exhibit Diels-Alder (DA) reactivity in a polymer matrix, which was modified with monomers containing furan groups. The DA-active polymer matrix was transferred into a dynamic reversible cross-linked inorganic-organic network via a Diels-Alder reaction with CNTs, where pristine CNTs were used as dienophile chemicals and furan-modified SBS acted as the macromolecular diene. In this system, the mechanical properties as well as resilience and solvent resistance were greatly improved even with the presence of only 1 wt % CNTs. Meanwhile, the hybrids retained recyclability and exhibited some smart behaviors, including self-healing and reprogrammable shape memory properties. Furthermore, due to the photothermal effect of CNTs, a retro-Diels-Alder (rDA) reaction was activated under laser irradiation, and healing of a crack on the hybrid surface was demonstrated in approximately 10 s with almost complete recovery of the mechanical properties. Such fast and efficient self-healing performance provides a new concept in designing self-healing nanocomposites with tunable structures and mechanical properties. Furthermore, the DA and rDA reactions could be combined to reprogram the shape memory behavior under laser irradiation or thermal treatment, wherein the temporary shape of the sample could be transferred to a permanent shape via the rDA reaction at high temperature.
原始碳纳米管 (CNT) 在含有呋喃基团的单体改性的聚合物基质中被激活以表现出 Diels-Alder (DA) 反应性。DA 活性聚合物基质通过与 CNT 的 Diels-Alder 反应转化为动态可逆交联的无机-有机网络，其中原始 CNT 用作双烯试剂，而呋喃改性 SBS 作为大分子二烯。在该体系中，即使只添加 1wt%的 CNT，力学性能以及弹性和耐溶剂性也得到了极大的提高。同时，该复合材料保持了可回收性，并表现出一些智能行为，包括自修复和可重编程的形状记忆性能。此外，由于 CNT 的光热效应，在激光照射下激活了逆 Diels-Alder (rDA) 反应，并在大约 10 秒内证明了在复合材料表面的裂纹可以得到修复，几乎完全恢复了其力学性能。这种快速高效的自修复性能为设计具有可调结构和力学性能的自修复纳米复合材料提供了一个新的概念。此外，DA 和 rDA 反应可以组合使用，在激光照射或热处理下重新编程形状记忆行为，其中通过高温下的 rDA 反应可以将样品的临时形状转换为永久形状。
