溶剂对聚乳酸纳米纤维膜孔隙结构及性能的影响

Effect of solvent on porous structure and properties of poly (lactic acid) nanofibrous membranes

为了获得兼具高效低阻和良好透气、透湿性能的纳米纤维膜材料,将聚乳酸（PLA）溶解在二氯甲烷（DCM）和N,N-二甲基乙酰胺（DMAC）形成的混合溶剂中,采用静电纺丝技术制备PLA多孔纳米纤维膜,并系统研究了DCM/DMAC质量比对纤维膜形态结构、透气性能、透湿性能和空气过滤性能的影响。结果表明：＂呼吸图案＂效应和热致相分离是纤维表面形成孔洞的主要机制,随着DCM含量的增加,纤维表面孔隙覆盖率逐渐增大,纤维膜的透气率先降低后升高,透湿率略有提高,过滤效率逐渐上升,阻力压降则先增大后减小,品质因子持续变大,说明在纳米纤维中形成多孔结构有助于改善材料的透气、透湿性能,并可以实现高效低阻的过滤效果,在口罩用过滤材料领域具有广阔的应用前景。

In order to obtain nanofibrous membranes with high-filtration efficiency, low-resistance and good-air permeability and moisture permeability, porous nanofibrous membranes are prepared by dissolving poly（lactic acid）（PLA） particles in a mixed solvent ofdichloromethane（DCM） and N, N-dimethyl acetamide（DMAC） through electrospinning. The influence of weight ratio of DCM/DMAC onmorphology, air and moisture permeabilities and air filtration property of the PLA membranes are investigated. The results show that thebreath figure and the thermally induced phase separation are the main mechanisms for pore formation. With the increase of DCM content, thepore coverage on fiber surface and the moisture permeability both increase, whereas the air permeability drops firstly and then rises. Thefiltration efficiency increases and the resistance increases initially and then decreases with the growing of DCM content. Furthermore, thequality factor keeps increasing. It can be inferred that nanofibrous membranes with porous structure are conducive to good air and moisturepermeabilities, and can realize excellent comprehensive air filtration performance, which has a broad application prospect in protective masks.