Preparation of Composite Particles Made of Biodegradable Polymer and a Few Additives with Phase Separation Followed by Drying-in-Liquid

It was tried to prepare the biodegradable composite particles by the phase separation method followed by the drying-in-liquid method. The composite particles were made of poly-ε-caprolac-tone, quaternary ammonium, carbon black and wax. In the experiment, acetone and water were selected as a good solvent and a poor solvent for poly-ε-caprolactone, quaternary ammonium and wax, respectively. The composite particles were prepared by changing the surfactant species and their concentration, the feeding velocity of water and the weight ratio of poly-ε-caprolactone with larger molecular weight to one with smaller molecular weight. The composite particles with the inner structure in which carbon black, quaternary ammonium and wax were coated well with poly-ε-caprolactone could be prepared by the preparation method presented in this study. The structure and the mean diameter of composite particles were strongly affected by the feeding ve-locity of water. The higher the feeding velocity of water, the larger the mean diameter of compo-site particles. The mean diameter was drastically decreased with the surfactant concentration an