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表面噴涂殼聚糖溶液對聚偏氟乙烯多孔膜的結(jié)構(gòu)和性能的影響

2021-04-26 15:58:19 作者：成世杰來源：材料研究學(xué)報分享至：

摘要

在聚偏氟乙烯（PVDF）溶液膜表面噴涂殼聚糖（CS）醋酸溶液，用浸沒相轉(zhuǎn)變法制備PVDF多孔膜，研究CS溶液對多孔膜的結(jié)構(gòu)和性能的影響并探討了成膜機(jī)理。結(jié)果表明，隨著溶液膜表面CS溶液體積的增加PVDF膜的孔隙率提高，膜表面的親水性大幅度提高，β晶含量降低而α晶的含量提高；噴涂CS溶液前PVDF膜的上表面結(jié)構(gòu)致密，噴涂CS溶液后PVDF膜上表面呈現(xiàn)多孔結(jié)構(gòu)，其斷面結(jié)構(gòu)均為指狀大孔結(jié)構(gòu)；噴涂CS溶液的體積為2 mL、4 mL和6 mL的PVDF膜，其水通量先增加后降低，分別為683.33 L/m2·h、1121.57 L/m2·h、1171.36 L/m2·h和1029.02 L/m2·h。用不同方法制備的PVDF膜，其結(jié)構(gòu)和性能不同，因為膜上表面的成膜機(jī)理不同。

關(guān)鍵詞：材料表面與界面 ; 聚偏氟乙烯多孔膜 ; 殼聚糖 ; 噴涂 ; 膜結(jié)構(gòu) ; 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