海藻酸钙/环氧微胶囊在水泥基材料中的自修复作用

Self-healing Effect of Calcium Alginate/Epoxy Microcapsules in Cementitious Materials

采用锐孔-凝固浴法制备海藻酸钙/环氧树脂复合微胶囊,将其应用于水泥基自修复材料。表征了微胶囊的微结构、力学强度和吸水溶胀等性能,并通过X射线计算机断层扫描技术和SEM/EDS分析微胶囊在水泥基材料中的修复作用机制。结果表明:制备的海藻酸钙微胶囊为三维网络支架结构;在粒径为0.7～2mm,粒径尺寸不影响微胶囊的强度;海藻酸钙含量决定微胶囊的强度、吸水率和溶胀率。海藻酸钙/环氧微胶囊的裂缝修复机制为:基体产生裂缝,微胶囊发生破裂释放环氧树脂,粘结裂缝;裂缝中有水渗入时,微胶囊吸水溶胀,堵塞裂缝,进而促进周围水泥颗粒的继续水化,修复裂缝。

Calcium alginate microcapsules loaded with epoxy were successfully prepared by a piercing-solidifying method, and applied to self-healing cementitious materials. The structure, mechanical strength and water swelling properties of the microcapsules were characterized, and the healing mechanism of microcapsules was monitored by X-ray computed tomography and SEM/EDS. The results showed that the microcapsules were three-dimensional network structures; the strength of the microcapsule with particle size of 0.7—2 mm was independent of the particle size; and the content of calcium alginate in microcapsule determined the strength, water absorption and swelling ratio of the microcapsule. The healing mechanism of calcium alginate/epoxy microcapsules in cement matrix was observed that when cracks formed, the microcapsules were broken to release the epoxy resin, bonding the cracks; when water penetrated into the cracks, the microcapsules absorbed and swelled, blocking the cracks and even promoted the cement particles continue to hydration, healing cracks.