Applied Polymer Research Laboratory, Department of Chemistry, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran.
Faculty of Civil Engineering, Sahand University of Technology, Tabriz, Iran.
J Microencapsul. 2021 Jun;38(4):203-217. doi: 10.1080/02652048.2021.1887382. Epub 2021 Mar 28.
This study was conducted to utilise the effective self-healing system to regain the mechanical properties of the cementitious materials containing micro-cracks.
Storing epoxy and calcium nitrate as healing agents was performed by microencapsulation in the urea-formaldehyde shell. The microcapsules were characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetric, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cementitious samples were prepared by mortar mixing with various amounts of microcapsules (0, 1, 3 and 6% w/w). The healing potential of microcapsules was analysed based on the recovery rate of the mechanical properties.
The obtained microcapsules have an outer rough surface, suitable diameter (1-100 μm) and shell thickness (0.2-0.6 µm), and remarkable thermal stability (up to 260 °C). Mechanical test results exhibit that created micro-cracks were healed completely and regained the recovery rates over 100%.
The prepared microcapsules besides enhancing thermal stability, demonstrate a high performance in microcracks sealing to improve durability of cementitious materials.
本研究旨在利用有效的自愈合系统来恢复含有微裂纹的胶凝材料的力学性能。
通过脲醛壳中的微胶囊化将环氧树脂和硝酸钙储存为愈合剂。通过傅里叶变换红外光谱、热重分析、差示扫描量热法、场发射扫描电子显微镜和能谱对微胶囊进行了表征。通过砂浆混合制备了含有不同量微胶囊（0、1、3 和 6%w/w）的胶凝样品。基于力学性能的恢复率分析了微胶囊的愈合潜力。
得到的微胶囊具有粗糙的外表面、合适的粒径（1-100μm）和壳厚（0.2-0.6μm）以及显著的热稳定性（高达 260°C）。力学测试结果表明，所产生的微裂纹完全愈合，恢复率超过 100%。
所制备的微胶囊除了提高热稳定性外，还在微裂纹密封方面表现出优异的性能，从而提高了胶凝材料的耐久性。
