一种共轴微通道反应器设计及单分散生物质聚合物微珠的可控制备

PREPARATION OF MONODESPERSE BIOPOLYMER MICROBEADS USING A NEW AND SIMPLE METHOD

采用不同尺寸的聚四氟乙烯（PTFE）微管为内外管、玻璃毛细管（glass capillary）或聚丙烯（PP）中空纤维为内管管头设计制作了一种共轴微通道反应器（N-CAMFR）.以聚乳酸（PLA）/二氯甲烷（CH2Cl2）溶液和海藻酸钠（Na-alginate）水溶液分别作为分散相,在N-CAMFR内形成O/W和W/O乳液后,收集乳液并使其中的液滴固化,制备出单分散的生物质聚合物微珠（BPM）.研究了固定管头尺寸时,改变连续相的流速及表面活性剂的种类对微珠尺寸的影响.结果表明,使用N-CAMFR制备微珠,反应过程流畅,所制得的微珠粒径分布均匀,其分散系数（f）可低至2.16%;通过改变内管管头的尺寸可方便地调控N-CAMFR的尺度,与传统微通道反应器相比,降低制作成本的同时拓宽了其应用的范围,而且降低了微通道反应器堵塞的几率.为粒径范围200-800μm的单分散聚合物微珠的可控连续制备提供了快捷绿色的新方法.

A new and simple method to prepare the monodisperse microbeads was developed for soluble polymers.Using a microchannel,we generated the uniform droplets by pushing the dispersed phase into the continuous phase and then solidified them by solvent-evaporation or gelation to obtain the PLA and sodium alginate microbeads.The microchannel was fabricated in our lab,and all of the materials were commercially produced.By using a frequency-modulation oscillator to help evaporation,the droplets can be solidified within 2 h,and especially the surface of the microbeads was smooth,and small pores with diameter of 1～2 μm were well-dispersed.By controlling the flow rates of the continuous phase conveniently,we could adjust the sizes of the microbeads.The diameters of the microbeads decreased from 460 μm to 342 μm when we increased the flow rates from 100 μL/min to 900 μL/min,and the lowest coefficients of variance of the microbeads was 2.16%.Also we studied the effect of the different continuous phases on the size of the microbeads,and it was believed that the size of the microbeads can be controlled by using different surfactants or mixing them in the continuous phase.