有机硅微胶囊粉末防水剂作用机理及性能

发布时间：2018-11-02 19:50

【摘要】：采用成膜微胶囊及喷雾干燥工艺制备了有机硅微胶囊粉末防水剂.试验研究了有机硅微胶囊粉末防水剂相对表面含油量、防水抗渗性能及其对水泥基材抗压强度、收缩性能以及孔结构等的影响.结果表明:有机硅微胶囊粉末防水剂的防水效果优于液态聚二甲基硅氧烷(PDMs)防水剂;采用3%(质量分数)辛基三乙氧基硅氧烷替代聚二甲基硅氧烷,砂浆浸水48h的吸水率可降低至3%~4%,抗渗压力增大48.9%,加载90d龄期的砂浆收缩率减少6.8%.扫描电镜(SEM)表明:微胶囊粉末防水剂为内核外壳结构,其中活性有机硅芯材与纳米碳酸钙填料被聚乙烯醇成膜包裹在其内部;经水解后,水溶性聚乙烯醇膜吸胀溶解,活性有机硅成分释放,参与形成有机硅疏水膜,起到防水效果,并提高了水泥水化程度,增强了基材密实性.
[Abstract]:Silicone microencapsulated powder water-repellent was prepared by film forming microcapsule and spray drying process. The relative oil content, waterproof and impermeability of silicone microencapsulated powder water-repellent agent and its influence on compressive strength, shrinkage and pore structure of cement substrate were studied. The results showed that the waterproof effect of silicone microencapsulated powder water-repellent was better than that of liquid polydimethylsiloxane (PDMs) water-repellent. When polydimethylsiloxane was replaced by 3% octyl triethoxysiloxane, the absorbency of mortar immersed in water for 48 hours could be reduced to 34%, the impermeability pressure increased 48.9%, and the shrinkage rate of mortar at 90 d age decreased by 6.8%. Scanning electron microscope (SEM) showed that the microencapsulated powder water-repellent was a core shell in which the active organosilicon core and nano-CaCO3 filler were encapsulated in the film by polyvinyl alcohol (PVA). After hydrolysis, the water-soluble polyvinyl alcohol membrane was absorbed and dissolved, and the active organosilicon component was released, which took part in the formation of silicone hydrophobic film, played a waterproof effect, improved the hydration degree of cement and enhanced the compactness of the base material.
【作者单位】：同济大学先进土木工程材料教育部重点实验室;
【分类号】：TU572

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