Surface Organic Modification of CaCO<sub>3</sub>-TiO<sub>2</sub> Composite Pigment
oleh: Sijia Sun, Hao Ding, Yanpeng Zha, Wanting Chen, Zhuoqun Xu
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2019-02-01 |
Deskripsi
To improve the properties and dispersibility of CaCO<sub>3</sub>-TiO<sub>2</sub> composite pigments (CaCO<sub>3</sub>-TiO<sub>2</sub>) in organic matrices, the surface modification of CaCO<sub>3</sub>-TiO<sub>2</sub> was performed with sodium stearate (SS) as an organic modifier by wet ultra-fine grinding in a stirred mill. The pigment properties of modified CaCO<sub>3</sub>-TiO<sub>2</sub> and its dispersibility in organic media were tested and characterized. The binding mechanism between CaCO<sub>3</sub>-TiO<sub>2</sub> 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 CaCO<sub>3</sub>-TiO<sub>2</sub>. After surface modification, the surface of CaCO<sub>3</sub>-TiO<sub>2</sub> turned from a hydrophilic surface to a hydrophobic surface and the surface free energy was reduced. In addition, the hiding property and dispersibility of CaCO<sub>3</sub>-TiO<sub>2</sub> in the organic medium were significantly improved. IR and XPS results indicated that the modifier SS was adsorbed on the surface of CaCO<sub>3</sub>-TiO<sub>2</sub> by chemical combination.