Preparation and characterization of Indigo Naturalis-Alumen composite particles based on particle design principle / 中草药

ABSTRACT

Objective: To prepare and characterize Indigo Naturalis-Alumen (INA) composite particles with core-shell structure based on the particle design principle. Methods: The preparation time of shell particles and composition time of composite particles were studied using particle size and contact angle as evaluation indexes, respectively. Four kinds of powders including Indigo Naturalis fine powder, Alumen fine powder, INA mixture, and INA composite particles were prepared respectively; Their properties such as particle size, powder color, microstructure, distribution of surface elements, and crystal structure were compared, so as to study the core-shell structure of composite particles. Results: During the period of the preparation, the shell particles were added into vibromill and ground for 17 min separately, and then the core particles were added and ground with shell particles together for 5 min. There was no difference between the composite particles and shell particles in surface wettability. The median diameter (d0.9) of the composite particles was 32.818 μm, which was much smaller than that of the mixture. The color and surface elements distribution were highly similar to the shell particles. In SEM, the microstructure that the surface of big particles coated with a large number of small particles could be observed. In X-ray diffractogram, many characteristic absorption b ands of the core particles were disappeared or decreased. Conclusion: INA composite particles with core-shell structure are prepared successfully, the surface properties are similar to the shell particles and are different with the core particles.