In this paper, a novel electromagnetic controlled rupture microcapsule (ECRM) with ultrahigh self-healing capability was prepared by melt condensation method, whose shell was constructed by nano-Fe₃O₄ and paraffin, and whose core was toluene-di-isocyanate (TDI). Effect of paraffin/TDI mass ratio on core fraction of ECRM was investigated. The morphology, particle size distribution and component identification of ECRM were characterized by cold field emission scanning electron microscope (CFE-SEM), laser particle analyzer and Fourier transform infrared spectrometer (FTIR), respectively. Subsequently, the effects of ECRM on mechanical propertyand self-healing ability of mortars were evaluated. The results showed that the paraffin/TDI mass ratio delivered a major impact on core fraction of ECRM. The core fraction of ECRM was 65.3% when the mass ratio of paraffin/TDI was 1:2. The particle size distribution of ECRM mainly ranged from 60 μm to 1258 μm with 600 rpm agitation rate. The ECRM exhibited ellipsoidal with a rough surface. FTIR confirmed the successfully encapsulation of TDI in the shell of paraffin and nano-Fe₃O₄. In addition, ECRM containing 10 wt% nano-Fe₃O₄ can be heated to higher than 60 ℃ under electromagnetic field (output voltage: 600 V, field frequency: 124 kHz) for 500 s. Compared to the control mortar, the compressive strength and the flexural strength of mortar showed positive correlation with the ECRM dosage increasing (0 to 4 wt%). The reserved ratio of compressive strength of damaged mortar containing 6% ECRM with 60% compressive strength preload was 91.4% after self-healing for 30 min under electromagnetic field and curing for 24 h at room temperature. This work is anticipated to afford new insights for solving rupture problems of microcapsules in self-healing cementitious materials.

本文采用熔融缩合法制备了一种具有超高自愈能力的新型电磁控制破裂微胶囊（ECRM），其外壳由纳米Fe ₃ O _4构成。和石蜡，其核心是甲苯二异氰酸酯（TDI）。研究了石蜡/ TDI质量比对ECRM核心部分的影响。用冷场发射扫描电子显微镜（CFE-SEM），激光颗粒分析仪和傅里叶变换红外光谱仪（FTIR）分别表征了ECRM的形貌，粒度分布和成分鉴定。随后，评估了ECRM对砂浆力学性能和自愈能力的影响。结果表明，石蜡/ TDI质量比对ECRM的核心部分有重大影响。当石蜡/ TDI的质量比为1：2时，ECRM的核心分数为65.3％。ECRM的粒径分布主要在60微米至1258微米之间，搅拌速度为600 rpm。ECRM呈现椭圆形且表面粗糙。₃ O ₄。此外，含有10 wt％纳米Fe ₃ O _4的ECRM可以在电磁场（输出电压：600 V，磁场频率：124 kHz）下加热到60℃以上，持续500 s。与对照砂浆相比，砂浆的抗压强度和弯曲强度与ECRM用量的增加（0至4 wt％）呈正相关。在电磁场下自我修复30分钟并在室温下固化24小时后，含6％ECRM和60％抗压预载的受损砂浆的抗压强度保留率为91.4％。预期这项工作将为解决自修复水泥材料中微胶囊的破裂问题提供新的见解。