无水硫酸钙晶须的无机–有机表面改性机理研究

Mechanism of Inorganic-organic Surface Modification of Anhydrous Calcium Sulfate Whisker

以硅酸钠为无机改性剂,硬脂酸为有机改性剂对无水硫酸钙晶须进行双重表面改性。通过接触角测试(WCA)、X射线衍射(XRD)、场发射扫描电镜(FESEM)、傅里叶红外光谱(FT-IR)和X射线光电子能谱(XPS)等多种分析手段对样品进行表征分析。实验结果表明:无机–有机改性后晶须表面性质由亲水性转变为疏水性,晶体结构未发生改变。在双重改性过程中,晶须表面首先生成–Ca–SiO_3结构,–Ca–SiO_3结构部分水解后,晶须表面与硬脂酸发生键合反应,生成–Ca–HSiO_3和–Ca–COOR结构包覆层,晶须表面不存在物理吸附作用。

Anhydrous calcium sulfate whisker （ACSw） was modified by dual-surface modification with sodium silicate solution as inorganic modifer and stearic acid as organic modifier. The samples were characterized by water contact angle （WCA）, X-ray diffraction （XRD）, field emission scanning electron microscope（FESEM）, fourier infrared spectrum （FT-IR）, and X-ray photoelectron spectroscope （XPS）. The results showed that ACSw surface property changed to Hydrophobic after inorganic-organic modification, while its crystal structure remained unchanged. FT-IR and XPS resutls indicated that -Ca-SiO3 structure was generated firstly on the surface of whiskers after reaction with sodium silicate solution. And then a mixing coating layer containing both -Ca-HSiO3 and -Ca-COOR structures were formed through bonding interaction with stearic acid rather than physical absorption after particle hydrolyzation of-Ca-SiO3 structure.