摘要
采用铝锆偶联剂对纳米碳酸钙进行表面改性.借助傅里叶红外光谱（FT-IR）、X射线衍射分析（XRD）、投射电镜（TEM）对改性前后的纳米碳酸钙的表面结构进行表征.FT-IR分析表明,铝锆偶联剂以化学键合和物理吸附的方式在纳米碳酸钙的表面形成吸附层,粒子表面存在羧基等等有机官能团的红外吸收特征.XRD分析证明,改性纳米碳酸钙保持原样品完整的体相结构,为方解石型纳米微晶.TEM分析显示,改性纳米碳酸钙呈立方体,平均粒径大约70 nm.通过颗粒粒度分布和表观粘度测量,对纳米碳酸钙的改性效果进行评价.实验表明,未改性纳米碳酸钙在水中存在明显的团聚现象,而铝锆偶联剂改性后的纳米碳酸钙的分散情况得到很大改善,颗粒粒度分布在70～100 nm之间,低剪切速率下的表观黏度大为降低,这为纳米碳酸钙在纸张涂料中的应用创造有利条件.
Surface modification of nanometer calcium carbonate （was abbreviated as nano-Ca- CO3） using zircoaluminate coupling agent was carried out in terms of the mass ratio of zircoaluminate coupling agent to nano-CaCO3. The surface structure of prepared samples was characterized by FT-IR, XRD and TEM. According to the spectra of FT-IR, it was inferred that chemical binding and physical adsorption between zircoaluminate coupling agent and nano-CaCO3 particles had happened during the modification reaction. It was confirmed by XRD that modified nano-CaCO3 samples kept the same bulk structure of pure calcium carbon- ate of calcite as unmodified CaCO3. The TEM images indicated that both unmodified and modified nano-CaCO3 were nearly cubic, and the average particle size of modified nano-Ca- CO3 was about 70 nm. The interfacial characteristics of nano-CaCO3 after modification were investigated according to the following parameters including particle size distribution and suspension viscosity determination. It was found that there was an obvious agglomeration in unmodified nano-CaCO3 particles. However, the particle dispersion of nano-CaCO3 after modification using zircoaluminate coupling agent was greatly improved and the interfacial rheology properties of high-concentrated nano-CaCO3 suspensions were also largely modified. Surface modification would be beneficial to the improvement of rheological behaviors of paper coating and paper properties when nano-CaCO3 was used in paper coating.
出处
《陕西科技大学学报（自然科学版）》
2007年第3期57-62,共6页
Journal of Shaanxi University of Science & Technology
基金
国家自然科学基金资助项目(20276025)
教育部植物资源化学与化工创新团队项目资助项目
关键词
纳米碳酸钙
铝锆偶联剂
表面改性
粒度
黏度
nano-CaCO3
zircoaluminate coupling agent
surface modification
particle size
viscosity
