Abstract:

To obtain strong hydrophobic property of silica，on the basis of traditional modification process with silane coupling agent stearic acid was introduced as complex modifier to modify the nano-silica powder. The modified silica particles were characterized with Fourier transform infrared analysis（FTIR），X-ray photoelectron spectroscopy（XPS），contact angle tests and sedimentation tests. The complex modification mechanism was also discussed. The results showed that amino group（—NH₂）was grafted successfully onto the surface of nano-silica particles by modification with silane coupling agent. After the second modification with stearic acid，amide bond（—CONH—）was formed by amino group（—NH₂）and carboxyl group（—COOH）of stearic acid. As a result，the —（CH₂）₃COHN—（CH₂）₁₆CH₃ group was obtained on the surface of nano-silica particles，which had excellent hydrophobic property. Because of the complex modification，the stearic acid molecules were grafted on the surface of nano-silica particles by chemical bonds，and the contact angle could reach 140°.

Key words:

纳米白炭黑, 表面接枝, 硅烷偶联剂, 硬脂酸

摘要：

为使纳米白炭黑具有强疏水性，在传统硅烷偶联剂改性工艺基础上，引入了硬脂酸进行复合改性，制备出了具有高疏水性能的纳米白炭黑。采用红外光谱（FTIR）、X射线光电子能谱（XPS）、接触角测试和沉降实验等研究了改性后试样的结构和性能，并讨论分析了复合改性的机理。结果表明：通过硅烷偶联剂改性，白炭黑表面接枝了氨基（—NH₂）基团；硬脂酸改性后，—NH₂基团与硬脂酸的羧基基团（—COOH）形成酰胺键（—CONH—），白炭黑最终表面形成了疏水性能优异的—（CH₂）₃COHN—（CH₂）₁₆CH₃基团。复合改性后的纳米白炭黑表面通过化学键接枝了硬脂酸分子，与水的接触角达到了140°，具有优异的疏水性能。

关键词:

纳米白炭黑, 表面接枝, 硅烷偶联剂, 硬脂酸