油酸钠改性无水硫酸钙晶须及其机理研究

采用油酸钠改性无水硫酸钙晶须(AW)，既可以增强无水硫酸钙晶须的疏水性，又可以在晶须表面引入-C=C-增加其功能性。利用晶须在甲基丙烯酸甲酯(MMA)的分散性能探究油酸钠加量、时间、改性温度等因素对改性效果的影响；采用XRD、XPS和DRIFTS探索晶须的吸附及改性机理、Washburn法测定晶须的疏水性能。结果表明随油酸钠用量的增加，分散性能先变好后变差，油酸钠与晶须质量比为1∶100时，沉降高度和沉降速度由油酸钠与晶须质量比为1∶200时的3.1 cm和0.31 cm/min大幅增加到10.6 cm和1.06 cm/min；分散性能开始出现突变时的油酸钠用量随温度升高而增加；DRIFTS表明油酸钠中的油酸根离子主要以物理吸附和化学吸附的方式与钙离子结合存在于晶须表面，其特征吸收峰分别是1 577 cm-1和1 540 cm-1的双峰和1 547 cm-1的单峰；改性后的晶须疏水性较改性前大幅增加，与水的接触角从改性前的0.04°增加到改性后的77.35°。

Abstract

Sodium oleate modified anhydrous calcium sulfate whiskers can not only enhance the hydrophobicity of anhydrite whiskers, but also introduce -C=C- groups on the surface of whiskers to increase its functionality. The influence of sodium oleate dosage, modification time and modification temperature on the modification effect was investigated by using the dispersion property of whisker in methyl methacrylate (MMA). The adsorption and modification mechanism of whiskers were explored by XRD, XPS and DRIFTS, the hydrophobicity of whiskers were determined by Washburn method. The results show that with the increase of sodium oleate dosage, the dispersion performance first becomes better and then becomes worse. When the mass ratio of sodium oleate to whisker is 1∶100, the settling height and settling velocity are greatly increased from 3.1 cm and 0.31 cm/min when the mass ratio of sodium oleate to whisker is 1∶200 to 10.6 cm and 1.06 cm/min, and the amount of sodium oleate when the dispersion performance starts to change suddenly increases with the temperature. DRIFTS show that oleate ions are mainly combined with calcium ions on the surface of the whiskers by physical adsorption and chemical adsorption, their characteristic absorption peaks are double peaks at 1 577 cm-1and 1 540 cm-1, and a single peak at 1 547 cm-1. The hydrophobicity of the modified whiskers is greatly increased compared with that before modification, and the contact angle with water increased from 0.04° before modification to 77.35° after modification.

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王明威, 曹建新, 谢贵明, 田生财, 陶绍程. 油酸钠改性无水硫酸钙晶须及其机理研究[J]. 人工晶体学报, 2020, 49(10): 1935. WANG Mingwei, CAO Jianxin, XIE Guiming, TIAN Shengcai, TAO Shaocheng. Modification of Anhydrous Calcium Sulfate Whiskers by Sodium Oleate and Its Mechanism[J]. Journal of Synthetic Crystals, 2020, 49(10): 1935.

油酸钠改性无水硫酸钙晶须及其机理研究

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