中文摘要：

以超临界抗溶剂雾化技术（SAS—A）从壳聚糖的乙醇水溶液中制备壳聚糖微粒，探讨预膨胀压力、溶液流量和浓度等工艺参数对微粒粒径和粒径分布的影响．结果表明，以超临界CO2流体为介质，预膨胀温度为50℃的条件下，采用SAS-A技术能制备得到壳聚糖球形微粒．通过改变操作条件可以控制微粒形态和大小：增大预膨胀压力，微粒平均粒径先增大，后稍减小；8MPa下微粒分布最均匀；增大溶液流量或增大溶液中壳聚糖的浓度，微粒粒径变大，粒径分布变宽；升高溶液中乙醇的体积分数，易形成球形微粒；增大喷嘴直径，微粒粒径稍变大，分布更均匀．在研究的操作条件下获得的壳聚糖微粒粒径大小主要在0．5～5．0μm之间．红外分析表明壳聚糖微粒化前后，结构没有明显变化．

英文摘要：

Supercritical fluid antisolvent-atomization（SAS-A）process was employed to prepare chitosan mieroparticles by using supercritical CO2 at the pre-expansion temperature of 50 ℃ from its water-ethanol solution. The process conditions such as pre-expansion pressure,solution flow rate, chitosan concentration in solution, ethanol volume fraction in solution and the nozzle size were investigated. The effects of these conditions on the particle morphology, size and size distribution were evaluated. Results showed that spherical chitosan particles with mean sizes of 0.5-5.0 μm could be produced by the SAS-A process except the ease at high ehitosan concentration. Increase of the pre-expansion pressure could first increase the particle size then decrease the particle size. At 8 MPa, ehitosan particles with the narrowest particle size distribution could be obtained. Increase of the chitosan concentration in solution or the solution flow rate could increase the particle size and broaden the particle size distribution. Increase of the ethanol concentration produced obviously more spherical particles. Increase of the nozzle size could slightly inerease the partiele size and narrow the particle size distribution. FTIR analysis showed that the chitosan had no evident structure change after the micronization process.