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采用静电纺丝法制备了孔径为40～150 nm的PLLA纳米孔结构超细纤维,纳米孔不仅分布在纤维表面,而且存在于纤维内部.通过扫面电镜观察了纤维表面形貌.探讨了混合溶剂二氯甲烷/N,N-二甲基甲酰胺的比例、PLLA浓度、电场强度对PLLA纤维纳米孔大小、分布密度、深度的影响.结果表明通过调节PLLA溶液性质和纺丝参数,PLLA纤维的表面形貌可以在3种状态即光滑无孔、疏浅凹坑、密集深孔之间可控.二氯甲烷/N,N-二甲基甲酰胺比例为1∶4,PLLA浓度9%,电场强度1 kV/cm,环境温湿度分别为30℃和52%,静电纺丝所得PLLA超细纤维表面孔洞直径为150 nm,孔洞分布密集.纳米孔PLLA纤维形成的主要机理是由于静电纺丝过程中溶剂的快速挥发引起纤维表面温度急剧降低导致热致相分离而产生多孔结构.PLLA纤维膜的疏水性与纤维表面孔洞结构密切相关,纤维膜接触角最高可达146.6°.由于PLLA纤维的多孔结构,这种高疏水性的PLLA纤维膜能够快速、大量地吸油,90 s内吸收柴油达到90 g/g,25 min内可以达到145 g/g.
The ultrafine fibers of PLLA nanowell with pore size of 40-150 nm were prepared by electrospinning. The nanopores were not only distributed on the surface of the fibers, but also existed inside the fibers. The surface morphology of the fibers was observed by scanning electron microscopy The influence of the ratio of dichloromethane / N, N-dimethylformamide, the concentration of PLLA and the electric field on the size, distribution density and depth of PLLA nanofibers was investigated. The results showed that by adjusting the properties of PLLA solution and spinning parameters, The morphology of the surface can be controlled between the three states of smooth nonporous, shallow pits and dense deep pores with the ratio of dichloromethane / N, N-dimethylformamide being 1: 4 and the concentration of PLLA being 9% , The electric field intensity is 1 kV / cm, the ambient temperature and humidity are respectively 30 ℃ and 52%, and the diameter of holes on the surface of PLLA microfibers obtained by electrospinning is 150 nm with dense distribution of holes.The main mechanism of nano-hole PLLA fiber formation is that electrospinning The rapid evaporation of the solvent during the spinning process caused the temperature of the fiber surface to decrease drastically, resulting in the thermal induced phase separation resulting in a porous structure.The hydrophobicity of the PLLA fiber membrane is closely related to the pore structure of the fiber surface, and the contact angle of the fiber membrane can reach up to 146.6 °. A porous structure, such high hydrophobic PLLA fiber membrane quickly, a large amount of oil absorption, 90 s to reach the diesel absorption 90 g / g, can reach 145 g / g within 25 min.