以色胺(Tryp)、聚(丙二醇)双(2-氨基丙醚)(D-400)和多聚甲醛为原料，简单共聚制备一系列吲哚基聚六氢三嗪(IN-PHT)聚合物薄膜材料，将聚合物薄膜用MgCl2 水溶液浸泡后烘干，得到Mg2+-吲哚动态交联的聚六氢三嗪(Mg-IN-PHT)薄膜材料。元素分布图证实，Mg2+在聚合物Mg-IN-PHT 中存在且分布均匀。利用理论计算模拟、紫外可见吸收光谱法、荧光光谱法等手段证明了Mg-IN-PHT 薄膜中Mg2+与吲哚基团间形成了阳离子- π相互作用。通过循环拉伸测试表征了Mg-IN-PHT 薄膜的力学性能，测试结果表明，Mg-IN-PHT 薄膜具有较强的拉伸强度(16.1 MPa)和韧性(206.2%)，明显高于IN-PHT 薄膜(11.0 MPa, 117.0%)。一方面，阳离子- π动态交联增大了聚合物网络中的交联密度，从而增强了薄膜的强度；另一方面，柔性聚合物网络受到外部刺激时易发生分子链的滑移，“ 点-面” 阳离子- π相互作用可以更容易地形成和解除，能量耗散效果较好，从而提高了材料的韧性。同时研究了薄膜材料的热稳定性变化，结果表明，Mg-IN-PHT 薄膜热分解温度(280 ℃)和玻璃化转变温度Tg(-10 ℃)均高于IN-PHT 薄膜的热分解温度(234 ℃)和Tg(-16 ℃)。另外，动态的“ 点-面” 阳离子- π相互作用赋予了Mg-IN-PHT 膜优异的可修复和可回收性能。
A series of indole-based poly(hexahydrozine) (IN-PHT) flexible film materials were prepared by simple copolymerization of tryptamine (Tryp), poly(propylene glycol) bis(2- aminopropyl ether) (D- 400) and paraformaldehyde, and the films were soaked in MgCl2 solution to prepare the Mg-poly(hexahydrozine) (Mg-IN-PHT) films crosslinked by Mg2+-indole interaction. The uniform distribution of Mg2+ in Mg-IN-PHT was confirmed by EDS. The formation of cation-π interaction between Mg2+ and indole was demonstrated by UV, RF and theoretical calculation. The mechanical properties of Mg- IN- PHT films were characterized by cyclic tensile test. The results indicate that Mg- IN-PHT films have the stronger tensile strength (16.1 MPa) and toughness (206.2%), which are significantly higher than IN-PHT films (11.0 MPa, 117.0%). On the one hand, cation- π cross-linking increases the cross-linking density, thus enhancing the strength of film; on the other hand, the molecular chains of flexible polymer network slip easily when it was externally stimulated. So that the "point- surface" cation- π interactions could be formed and released more easily, and the energy dissipation effect is better, thus the toughness of film is improved. In addition, the thermal stability of Mg- IN- PHT was also investigated. The results indicate that the thermal decomposition temperature (280 ℃) and Tg (-10 ℃) of Mg-IN-PHT films are higher than those of IN-PHT films (234℃ ) and (- 16℃ ). Finally, the dynamic “point- surface” cation- π interaction endows Mg- IN- PHT films with excellent self-healing and recycling abilities.
吴禄锟, 李亿程, 张林, 常冠军.基于动态Mg2+-吲哚的可修复可回收聚六氢三嗪薄膜的制备及性能[J].高分子材料科学与工程,2022,38(9):124-131.复制