气溶胶溶剂萃取系统技术制备聚乳酸微细颗粒

Preparation of PLA microparticles by ASES technique

采用气溶胶溶剂萃取系统制备聚乳酸(PLA)微细颗粒.用扫描电镜考察了工艺参数温度(35～55℃)、压力(8～20MPa)、PLA溶液浓度(0.1～0.5g·ml-1)及其流速(140～400ml·h-1)、PLA相对分子质量(Mw:10000～100000)对产品颗粒形貌及粒径的影响;采用X射线衍射谱仪分析了产品的结晶性能.结果表明,当Mw=100000或PLA溶液浓度达到1g·ml-1时,产品为黏性薄膜,无法得到微球状颗粒产品,当Mw小于100000或PLA溶液浓度小于1g·ml-1时,产品为微球状颗粒,在本研究范围内,温度和压力是影响粒径的主要因素,升高压力、降低温度可显著降低PLA颗粒粒径.在20MPa,35℃,PLA溶液流速为240ml·h-1、浓度0.1g·ml-1、相对分子质量Mw=10000条件下成功制备了粒径介于200～600nm的PLA微球.XRD分析显示产品晶型几乎没有变化,但结晶度大大减小.

Poly lactic acid （PLA） microparticles were prepared by a supercritical fluid method, called the aerosol solvent extraction system method. The effects of pressure, temperature, PLA solution concentration and its flow rates, and PLA molecular weight （Mw） on the morphology and particle size （PS） of the resulting PLA microparticles were investigated. The results showed that a viscous film was found at sinter filter fixed on the bottom of the precipitator when Mw was 100000, or PLA solution concentration was 1 g·ml^-1 , when Mw was less than 100000 or PLA solution concentration was smaller than 1g·ml^-1 , PLA microparticles were produced. In the scope of study here, pressure and temperature were the most significant factors on PS, and increasing pressure, or decreasing temperature could lead to a significant decrease in PS. At 20 MPa, 35℃, PLA flow rate 240 ml·ml^-1, concention 0.1g ·ml^-1, M.=10000, the PLA microparticles with a PS of 200-600 nm were successfully obtained. XRD suggested that there was no significant change in crystalline type, but significant decrease in the crystallinity of the resulting PLA products was observed.