纳米白炭黑的复合改性及性能表征

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。

Complex-modification and characterization of nano-silica

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(-NH_2)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(-NH_2)and carboxyl group(-COOH)of stearic acid.As a result,the -(CH_2)_3COHN-(CH_2)_(16)CH_3 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°.