Zhu Siyao, Wang Yan, Qin Jiaxin, Chen Li, Zhang Liying, Wei Yi, Liu Wanshuang
Shanghai High Performance Fibers and Composites Center (Province-Ministry Joint), Shanghai Key Laboratory of Lightweight Composite, Center for Civil Aviation Composites, Donghua University 2999 North Renmin Road Shanghai China
Key Laboratory of Textile Science &Technology, Ministry of Education, College of Textiles, Donghua University 2999 North Renmin Road Shanghai 201620 China.
RSC Adv. 2023 Oct 2;13(41):28658-28665. doi: 10.1039/d3ra05413f. eCollection 2023 Sep 26.
This work proposes a strategy to address the challenge of achieving rapid reprocessability of vitrimers at mild temperatures by introducing dynamic disulfide and hemiaminal bonds into hemiaminal dynamic covalent networks (HDCNs). The resulting HDCNs, termed HDCNs-DTDA, were prepared through a facile polycondensation between formaldehyde and 4,4'-dithiodianiline. The dual dynamic bond system in the HDCNs-DTDA enables rapid stress relaxation under mild temperature (65 °C for 54 s), which is significantly faster than that observed in HDCNs containing a single dynamic bond (HDCNs-DDM). The HDCNs-DTDA also exhibit a glass transition temperature of 96 °C, excellent solvent resistance and high recovery rates (97%) of tensile strength after reprocessing. In addition, HDCNs-DTDA can be easily degraded in HCl and thiol solutions at room temperature to enable chemical recyclability. Finally, HDCNs-DTDA demonstrates fast shape memory behaviors using thermal stimulation.
本工作提出了一种策略，通过将动态二硫键和半缩醛胺键引入半缩醛胺动态共价网络（HDCNs）来应对在温和温度下实现热致液晶聚合物快速再加工性的挑战。由此产生的HDCNs，称为HDCNs-DTDA，是通过甲醛与4,4'-二硫代二苯胺之间的简便缩聚反应制备的。HDCNs-DTDA中的双动态键系统能够在温和温度（65°C，54秒）下实现快速应力松弛，这比在含有单一动态键的HDCNs（HDCNs-DDM）中观察到的速度要快得多。HDCNs-DTDA还表现出96°C的玻璃化转变温度、优异的耐溶剂性以及再加工后97%的高拉伸强度恢复率。此外，HDCNs-DTDA在室温下可在HCl和硫醇溶液中轻松降解，以实现化学可回收性。最后，HDCNs-DTDA利用热刺激表现出快速的形状记忆行为。
