Zheng Nan, Liu Jie, Li Wenge
Shaanxi Key Laboratory of Catalysis, School of Chemical and Environmental Science, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, China.
School of Materials Science and Engineering, Shaanxi Key Laboratory of Catalysis, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, China.
Polymers (Basel). 2019 Jul 2;11(7):1127. doi: 10.3390/polym11071127.
Thermoset epoxies are widely used due to their excellent properties, but conventional epoxies require a complicated and time-consuming curing process, and they cannot self-healed, which limits their applications in self-healing materials. Extrinsic and intrinsic self-healing materials are applied in various fields due to their respective characteristics, but there is a lack of comparison between the two types of healing systems. Based on this, a thiol-epoxide click reaction catalyzed by an organic base was introduced to achieve the efficient preparation of thiol-epoxy. Furthermore, tung oil (TO)-loaded microcapsules were introduced into the thiol-epoxy matrix of dynamic transesterification to obtain a TO/TMMP-TMTGE self-healing composite with an intrinsic-extrinsic double-healing system. For comparison, a TMMP-TMTGE self-healing material with an intrinsic healing system was also prepared, which contained only thiol and epoxy curing chemistries. The effect of the core/shell ratio on the morphology, average particle size, and core content of TO-loaded microcapsules was studied. It was found that when the core/shell ratio was 3:1, the average particle size of the microcapsules was about 99.8 μm, and the microcapsules showed good monodispersity, as well as a core content of about 58.91%. The differential scanning calorimetry (DSC) results showed that the TO core was successfully encapsulated and remained effective after encapsulation. Furthermore, scanning electron microscopy (SEM), atomic force microscopy (AFM), tensile tests, and electrochemical tests were carried out for the two types of self-healing materials. The results showed that the TO/TMMP-TMTGE composite and TMMP-TMTGE material both had self-healing properties. In addition, the TO/TMMP-TMTGE composite was superior to the TMMP-TMTGE material due to its better self-healing performance, mechanical strength, and corrosion protection performance.
热固性环氧树脂因其优异的性能而被广泛使用，但传统环氧树脂需要复杂且耗时的固化过程，并且它们无法自我修复，这限制了它们在自修复材料中的应用。外在和内在自修复材料因其各自的特性而应用于各个领域，但这两种修复系统之间缺乏比较。基于此，引入了有机碱催化的硫醇-环氧化合物点击反应以实现硫醇-环氧树脂的高效制备。此外，将负载桐油（TO）的微胶囊引入动态酯交换的硫醇-环氧树脂基体中，以获得具有内在-外在双重修复系统的TO/TMMP-TMTGE自修复复合材料。为了进行比较，还制备了具有内在修复系统的TMMP-TMTGE自修复材料，其仅包含硫醇和环氧固化化学体系。研究了核壳比对负载TO微胶囊的形态、平均粒径和核含量的影响。发现当核壳比为3:1时，微胶囊的平均粒径约为99.8μm，微胶囊表现出良好的单分散性，核含量约为58.91%。差示扫描量热法（DSC）结果表明，TO核被成功封装，封装后仍保持有效。此外，对两种自修复材料进行了扫描电子显微镜（SEM）、原子力显微镜（AFM）、拉伸试验和电化学试验。结果表明，TO/TMMP-TMTGE复合材料和TMMP-TMTGE材料均具有自修复性能。此外，TO/TMMP-TMTGE复合材料由于其更好的自修复性能、机械强度和耐腐蚀性能而优于TMMP-TMTGE材料。
