表面活性剂在干燥中控制粒子团聚的机理

Effect of Surfactant in Controlling Particle Agglomeration during Drying Process

以中和沉淀法制备超细氢氧化铝粉,通过粉末的粒度分析和粒子数的计算,研究了干燥时表面活性剂对超细粒子团聚的影响规律。结果表明:若不加表面活性剂,粒子团聚严重,小于0.2μm的粒子消失,粒子总数减少了99.9%,干燥后粉体表面孔径分布不均匀,粒子易成快。加入表面活性剂后,细粒子团聚程度降低,粒子总数减少小于30%,干燥后粉体气孔发达,分布均匀。N2吸附-脱附曲线和SEM分析结果表明,加入表面活性剂后,由于表面活性剂吸附在界面上,影响了粒子表面性质,影响粉体中孔的结构和大小,从而导致了毛细管力的变化,影响了粒子间氢键及架桥氢键的生成,继而抑制了粒子的团聚。

The agglomeration occurred during the drying process of uhrafine aluminum hydroxide, prepared by neutralization precipitation, was investigated by analyzing the particle size and counting the particle number, and the influence of surfactants therein was studied. Without the presence of surfactants, particles inclined to agglomerate during the drying process, as the particle number decreased by 99.9% since the particle smaller than 2 μm in diameter disappeared, while the pore in the hard block of the dried powder was not uniform in size. In contrast, the agglomeration became less serious with the addition of surfactants, as the total number of particles decreased by less than 30% , and more poles, homogeneously distributed in the dried sample, were observed. N2 adsorption-desorption isotherm and SEM characterization show that the interfacial properties of particles and the capillary pressure were changed sorption, and the structure and the pore size were also altered. The formation of hydrogen therefore restrained, while the agglomeration process was effectively controlled. owing to the surfactant ad- bond among particles was