基于金属配位键自修复聚氨酯的制备与表征

Preparation and characterization of self-healing polyurethane based on metal coordination bond

摘要:

金属-配体配位因其动态性质和不同的缔合强度使其作为交联剂在超分子化学中备受关注。为了使聚氨酯胶膜兼具良好的机械强度与自修复能力,在本研究中,首先以2, 6-二氨基吡啶(DAP)作为扩链剂合成了聚氨酯(PU-DAP),然后以不同用量的无水氯化铁作为交联剂与PU-DAP进行配位交联,合成了一系列自修复聚氨酯胶膜(PU-DAP/ Fe₃₊⁾。单因素实验结果表明：当n(DAP): n(Fe₃₊^)=2:1时,胶膜的机械性能与自修复性能最佳；红外测试结果表明：Fe₃₊^{与吡啶和酰胺基团上的氮和氧成功配位}；热重分析结果证明, PU-DAP/Fe₃₊^{胶膜的热分解温度提高了}17.15 ℃,引入Fe₃₊^{所形成的配位交联结构有效提高了热稳定性。自修复实验和偏光显微镜观察结果证明},胶膜的拉伸强度与修复效率分别为5.16 MPa和93.2%,室温修复36 h划痕几乎完全消失；与未加Fe₃₊^的PU-DAP相比,其机械强度和自修复率均有所提升。

Abstract:

The metal-ligand coordination, as a crosslinking agent, has attracted much attention in supramolecular chemistry because of its dynamic properties and different association strengths. In order to make polyurethane film have better mechanical strength and self-healing efficiency, in this study, the polyurethane (PU-DAP) was synthesized by using 2, 6-diaminopyridine (DAP) as chain extender, and then different amounts of anhydrous ferric chloride were used as crosslinking agent to coordinate with PU-DAP. A series of self-healing polyurethane films (PU-DAP/ Fe₃₊^{) w}ere synthesized. The single factor experiment results showed that when n(DAP): n(Fe₃₊⁾ was 2:1, the mechanical properties and self-healing properties of PU-DAP/Fe_3+^2:1 film were the best. The FTIR results showed that Fe₃₊ was successfully coordinated with nitrogen and oxygen on pyridine and amide groups. The thermogravimetric analysis results showed that the thermal decomposition temperature of PU-DAP/Fe_3+^2:1 film was increased by 17.15 ℃, which indicated that the thermal stability was enhanced by the crosslinking structure formed via the introduction of Fe^₃₊. The self-healing experiment and polarizing microscope testing results showed that the tensile strength and self-healing efficiency of the film were 5.16 MPa and 93.2%, respectively. And the scratches completely disappeared after 36 h at room temperature. Compared with PU-DAP, its mechanical strength and self-healing efficiency were both improved.