亲水型PVDF/PBS共混物纤维膜及其油/水分离性能

Hydrophilic PVDF/PBS blend fabric membranes and their oil/water separation property

亲水型聚偏氟乙烯(PVDF)基分离膜及其制备新方法的开发有助于推动PVDF在分离膜领域的大规模应用。本文利用聚丁二酸丁二醇酯(PBS)与PVDF共混以改善其亲水性,并采用静电纺丝法制备了PVDF/PBS共混物纤维膜,研究和分析了纤维膜的微观结构、亲水性能、油/水分离性能之间的内在联系。研究结果表明,纤维的平均直径和孔隙率都随PBS含量的增加而降低。由于较好的相容性,在共混物纤维膜中PVDF相抑制了PBS相的结晶,而PBS相也在一定程度上抑制了PVDFβ晶型的形成。PBS相的混入改善了共混物纤维膜的亲水性,使水滴易于渗过,但阻止油滴通过,从而实现油/水分离的效果。PBS质量分数为30%时共混物纤维膜的分离效果最优,这主要归因于70/30 PVDF/PBS共混物纤维膜良好的亲水性,此外,较细的纤维直径也使其孔径减小而有利于提高分离效果。

Developing hydrophilic PVDF-based membranes and their new preparation methods is helpful for the large scale use of PVDF in membrane separation. In this paper,PBS was blended with PVDF to improve its hydrophility. PVDF/PBS blend fabric membranes were prepared via electrospinning,and their microstructures-hydrophility-oil/water separation property relationship was studied. The results showed that the average diameter and porosity of the fibers were decreased with an increase of the content of PBS component. Due to relatively good miscibility,the PVDF component hindered the crystallization of the PBS component,while the formation of β-phase crystal of the PVDF component was hindered by the PBS component to some extent. The presence of PBS component improved the hydrophility of the fabric membranes,so water could easily go through the fabric membranes,whereas the oil could not,and thus the oil and water could be separated. At the PBS content of 30%,the best separation efficiency was obtained,which could be mainly ascribed to the good hydrophility of the 70/30 PVDF/PBS blend fabric membranes as well as the small diameter of the fibers which decreased the pore size of the fabric membranes,and helped to improve the separation efficiency.