纳米碳酸钙的原位包覆及应用

In-situ encapsulation and application of nano-sized calcium carbonate

为更好地改性纳米碳酸钙,采用脂肪酸(SA)对纳米碳酸钙进行原位包覆,并对原位包覆法机理作了探讨。先在纳米碳酸钙浆液中加入一定量强碱,然后将浆液加热至75.0～90.0℃,再在机械搅拌辅助下加入适量脂肪酸,浆液经过滤、干燥和粉碎解聚得表面包覆改性的纳米碳酸钙。包覆碳酸钙的吸油值、接触角测试,扫描电子显微镜表征及其在室温硫化硅橡胶和DOP糊中的应用实验表明:脂肪酸在纳米碳酸钙表面形成均匀、完整的包覆层,改性碳酸钙在聚合物中具有极佳的应用效果。研究发现,温度为90℃,n(SA+OA)∶n(OH-)=1∶1,n(SA+OA)/m(CaCO3)=1.0×10-4mol/g是原位法表面包覆纳米碳酸钙比较合适的条件。

In order to modify the nano-sized calcium carbonate better, fatty acid was adopted to dope it in-situ and the mechanism of in-situ encapsulation was discussed.An appropriate amount of alkali was introduced to some just prepared milk of nano-sized calcium carbonate which followed by being heated to 75.0-90.0℃.By the aid of stirring,needed amount of fatty acid was added into the milk.After filtrating, drying, and pulverizing, nano-sized encapsulated calcium carbonate powders were obtained.Characterization of oil absorption, contact angles, and scanning electron microscopy of the powders, and their filling application experiments in vulcanized silicone rubber and DOP in room temperature indicated： each calcium carbonate particle was uniformly and thoroughly encapsulated by fatty acid, and the calcium carbonate fillers could drastically enhance some properties of polymer.Research showed that 90℃, n （SA＋OA） ：n （OH^-） =1：1 and n （SA＋OA）/m （CaCO3） =l.0× 10^-4 mol/g were the suitable conditions for the in-situ encapsulation of nano-sized calcium carbonate.