聚碳酸酯/聚乳酸复合多孔膜的淬火法形成与控制

Fabcrication and Control of PC/PLA Composite Porous Membrane by Quenching Method

以聚碳酸酯(PC)和聚乳酸(PLA)为成膜的双组分原料,六氟异丙醇(HFIP)为复合聚合物的共溶剂,甲醇为非溶剂,利用淬火法成功制备了PC/PLA复合多孔膜材料。研究了HFIP浓度、淬火时间、淬火温度和PC/PLA质量配比对所获得的多孔膜形貌结构上的影响,并解释了可能的形成机理。最佳的成膜条件为6g/mL的HFIP浓度、2h的淬火时间、0℃的淬火温度和1/1的PC/PLA质量配比。实验结果表明:非溶剂作用下的淬火相分离和溶剂的先后挥发,分别对应液-固和液-液两分相过程,直接受溶液粘度和表面张力控制。适宜的实验条件下,得到孔径分布均匀和贯通性良好的分层多孔结构;其它条件下或是得到大尺寸、无规整的断孔,或是单层、不均匀的孔结构,亦或是片层、仅有少数孤立小孔的致密结构。

Polycarbonate(PC)/Polylactic acid(PLA)composite porous membrane structure of double components PC and PLA were prepared by quenching method under Hexafluoro-isopropanol(HFIP)as co-solvent and methanol as non-solvent.The effects of factors,such as HFIP concentration,quenching time,quenching temperature and PC/PLA mass ratio,on the morphology and structure of the porous membrane were investigated.The optimum conditions were:6 g/mL HFIP concentration,2 h quenching time,0℃quenching temperature and 1/1 PC/PLA mass ratio.A possible mechanism was proposed.The results show that:the quenching phase separation under non-solvent and the pore formation rate of solvent evaporation successively correspond to the liquid-solid and liquid-liquid two-phase processes respectively,which are directly controlled by solution viscosity and surface tension.Under the suitable experimental conditions,the layered porous structure with uniform pore size distribution and good penetration are obtained.Whereas,Other conditions can be a large size and irregular hole broken structure,or a single layer and uneven hole structure,or be lamellar and only a few isolated holes dense structure.