碳酸钙的原位合成及表面改性

In Situ Synthesis and Surface Modification of Calcium Carbonate

利用碳化法,选用几种常见的改性剂(硬脂酸钠、十八碳醇磷酸酯和油酸)对碳酸钙进行了原位合成及表面改性.通过活化度、白度、接触角的测定,对比了其改性效果,同时通过傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、透射电镜(TEM)等测试手段对产品进行表征.FT-IR结果表明,改性剂与碳酸钙表面是以化学键合和物理吸附方式相结合.碳酸钙改性后,其红外ν3特征吸收峰出现约44cm-1的蓝移现象.对反应机理进行了初步探讨.实验结果表明,当十八碳醇磷酸酯用量达到2%(以碳酸钙的质量分数计)时,产品活化度达到99.9%,白度值达到97.3%,接触角达到了122.25°,从而为新型无机填料的制备提供了理论依据和合成手段.

We prepared hydrophobic calcium carbonate nanoparticles in situ via the carbonation route with various modifiers such as sodium stearate （NaSt）, octadecyl dihydrogen phosphate （ODP）, and oleic acid （OA）. The modification of CaCO3 was determined by measuring its active ratio, whiteness and the contact angle. The products were characterized by Fourier transform infrared spectroscopy （FF-IR）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. FT-IR spectra revealed that chemical bond and physical adsorption between modifiers and CaCO3 happened during the modification reaction. The infrared absorption peak of the modified CaCO3 was blue shifted 44 cm^-1 compared with the unmodified CaCO3. A preliminary reaction mechanism was discussed in this paper. At a 2%（w（CaCO3）） modifier dosage, the active ratio of CaCO3 as modified by ODP was 99.9% and the whiteness was 97.3%. The contact angle was 122.25° for the CaCO3 modified in the presence of ODP. The theory to support these findings and synthetic methods was presented for these novel materials.