Surface Organic Modification of CaCO3-TiO2 Composite Pigment
2019
Sijia Sun | Hao Ding | Yanpeng Zha | Wanting Chen | Zhuoqun Xu
To improve the properties and dispersibility of CaCO3-TiO2 composite pigments (CaCO3-TiO2) in organic matrices, the surface modification of CaCO3-TiO2 was performed with sodium stearate (SS) as an organic modifier by wet ultra-fine grinding in a stirred mill. The pigment properties of modified CaCO3-TiO2 and its dispersibility in organic media were tested and characterized. The binding mechanism between CaCO3-TiO2 and SS was explored by infrared spectrometry (IR) and X-ray photoelectron energy spectroscopy (XPS). The results showed that the mechanical grinding strength and SS dosage had a significant effect on the activation index and sedimentation rate of CaCO3-TiO2. After surface modification, the surface of CaCO3-TiO2 turned from a hydrophilic surface to a hydrophobic surface and the surface free energy was reduced. In addition, the hiding property and dispersibility of CaCO3-TiO2 in the organic medium were significantly improved. IR and XPS results indicated that the modifier SS was adsorbed on the surface of CaCO3-TiO2 by chemical combination.
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