表面喷涂壳聚糖溶液对聚偏氟乙烯多孔膜的结构和性能的影响

2021-04-26 15:58:19 作者：成世杰来源：材料研究学报分享至：

摘要

在聚偏氟乙烯（PVDF）溶液膜表面喷涂壳聚糖（CS）醋酸溶液，用浸没相转变法制备PVDF多孔膜，研究CS溶液对多孔膜的结构和性能的影响并探讨了成膜机理。结果表明，随着溶液膜表面CS溶液体积的增加PVDF膜的孔隙率提高，膜表面的亲水性大幅度提高，β晶含量降低而α晶的含量提高；喷涂CS溶液前PVDF膜的上表面结构致密，喷涂CS溶液后PVDF膜上表面呈现多孔结构，其断面结构均为指状大孔结构；喷涂CS溶液的体积为2 mL、4 mL和6 mL的PVDF膜，其水通量先增加后降低，分别为683.33 L/m2·h、1121.57 L/m2·h、1171.36 L/m2·h和1029.02 L/m2·h。用不同方法制备的PVDF膜，其结构和性能不同，因为膜上表面的成膜机理不同。

关键词：材料表面与界面 ; 聚偏氟乙烯多孔膜 ; 壳聚糖 ; 喷涂 ; 膜结构 ; 水通量

Abstract

After spraying acetic acid solution of chitosan （CS） on polyvinylidene fluoride （PVDF） solution film, PVDF porous membrane was prepared by immersion precipitation phase inversion method. The effect of the volume of CS solution on the structure and properties of porous membrane was investigated, and the mechanism of membrane formation was discussed. The results show that with the increase of CS solution volume the porosity and the surface hydrophilicity of the prepared PVDF membrane increased, the content of β crystal on the top surface decreased, while the content of α crystal increased. The top surface of plain PVDF membrane prepared with the PVDF solution film without sprayed CS solution has dense structure, while the upper surface of PVDF membrane prepared with the PVDF solution film after CS solution spraying has porous structure. The cross-section structure of all PVDF membranes is finger like macroporous structure. When CS solution volume was 2 mL, 4 mL and 6 mL, the water flux of corresponding PVDF membranes first increased and then decreased, which are 683.33 L/m2h, 1121.57 L/m2h, 1171.36 L/m2h and 1029.02 L/m2h, respectively. The difference in structure and properties of PVDF membranes prepared with different procedure was mainly due to the different formation mechanism for the top layer of the membranes.

Keywords： surface and interface in the materials ; polyvinylidene fluoride porous membrane ; chitosan ; spraying ; membrane structure ; water flux