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目的基于粒子设计原理,制备并表征具有核壳结构的青黛-白矾复合粒子。方法以粒径为评价指标,研究壳粒子的制备时间;以接触角为评价指标,研究复合粒子的复合时间。分别制备青黛细粉、白矾细粉、青黛-白矾细粉混合物及青黛-白矾复合粒子,从粒径分布、粉末颜色、微观结构、表面元素分布及晶型结构方面对比研究4种粉末的差异,以表征复合粒子的核壳结构。结果壳粒子在振动磨中粉碎17 min后加入核粒子,两者一起复合5 min,复合粒子的表面润湿性与壳粒子无显著差异。4种粉末在粒径分布、颜色、微观结构、表面元素分布及晶型结构上存在显著差异;复合粒子的众位粒径d0.9为32.818μm,远小于混合物,其颜色、表面元素分布与壳粒子高度类似,扫描电镜(SEM)观察到存在众多小颗粒包覆在大颗粒表面的微观结构,X射线衍射谱中核粒子大部分的特征峰消失或强度减弱。结论成功制备出了具有核壳结构的青黛-白矾复合粒子,其表面性质与壳粒子类似,与核粒子明显不同。
Objective To prepare and characterize the indigo-alum composite particles with core-shell structure based on the principle of particle design. Methods The particle size was used as the evaluation index to study the preparation time of the shell particles. The contact angle was used as the evaluation index to study the complexing time of the composite particles. The differences of four kinds of powders were compared in terms of particle size distribution, powder color, microstructure, surface elemental distribution and crystal structure, respectively, to prepare indigo powder, alum powder, indigo - alum powder mixture and indigo - alum composite particles. To characterize the core-shell structure of the composite particles. Results The shell particles were crushed for 17 min in a vibrating mill, and then the core particles were added for 5 min. The surface wettability of the composite particles was not significantly different from that of the shell particles. There were significant differences in the particle size distribution, color, microstructure, surface elemental distribution and crystal structure among the four powders. The particle size d0.9 of the composite particles was 32.818μm, which was much smaller than the mixture. The color, surface elemental distribution and The shell particles are highly similar. The microscopic structure of many small particles coated on the surface of large particles is observed by scanning electron microscopy (SEM). Most of the characteristic peaks disappear or weaken in the X-ray diffraction spectrum. Conclusion The indigo-alum composite particles with core-shell structure were successfully prepared. Their surface properties were similar to those of shell particles, which were obviously different from those of core particles.