Synergistic action of non-solvent induced phase separation in preparation of poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation

Abstract

A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation (TIPS) has been carried out. The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed, which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation (NIPS), because of the synergistic action of non-solvent induced phase separation at air gap zero. The pore size gradually decreases from outer surface layer to the intermediate layer, but increases gradually from intermediate layer to the inner surface layer. With the increase of air gap distance, the pore size near the outer surface gets smaller and a dense skin layer is formed, and the pore size gradually increases from the outer surface layer to the inner surface layer. Water permeability of the hollow fiber membrane decreases with air gap distance, the water permeability decreases sharply from 45.50×10⁻⁷ to 4.52×10⁻⁷ m³/(m²·s·kPa) as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s, further decreases from 4.52×10⁻⁷ to 1.00×10⁻⁸ m³/(m²·s·kPa) as the air gap increases from 10 to 40 mm. Both the breaking strength and the elongation increase with the increase of air gap distance. The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.

Keywords

thermally induced phase separation / hollow fiber membranes / synergistic action / hydrophilic membrane

References

[1] FengC Y, KhulbeK C, MatsuuraT, IsmailA F. Recent progresses in polymeric hollow fiber membrane preparation, characterization and applications [J]. Sep Purif Technol, 2013, 111: 43-71

[2] ZhaoY-h, WeeK H, BaiR-bi. Highly hydrophilic and low-protein-fouling polypropylene membrane prepared by surface modification with sulfobetaine-based zwitterionic polymer through a combined surface polymerization method [J]. J Membr Sci, 2010, 362(1/2): 326-333

[3] MaximousN, NakhlaG, WanW. Comparative assessment of hydrophobic and hydrophilic membrane fouling in wastewater applications [J]. J Membr Sci, 2009, 339(1/2): 93-99

[4] QiuY-r, MatsuyamaH. Preparation and characterization of poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation with diluent polyethylene glycol 200 [J]. Desalination, 2010, 257: 117-123

[5] RajabzadehS, MaruyamaT, OhmukaiY, SotaniT, MatsuyamaH. Preparation of PVDF/PMMA blend hollow fiber membrane via thermally induced phase separation (TIPS) method [J]. Sep Purif Technol, 2009, 66(1): 76-83

[6] KhulbeK C, FengC Y, HamadF, MatsuuraT, KhayetM. Structural and performance study of microporous polyetherimide hollow fiber membranes prepared at different air-gap [J]. J Membr Sci, 2004, 245: 191-198

[7] KhayetM. The effects of air gap length on the internal and external morphology of hollow fiber membranes [J]. Chem Eng Sci, 2003, 58: 3091-3104

[8] KhayetM, Garcia-payoM C, QusayF A, ZubaidyM A. Structural and performance studies of poly(vinyl chloride) hollow fiber membranes prepared at different air gap lengths [J]. J Membr Sci, 2009, 330(1/2): 30-39

[9] RajabzadehS, MaruyamaT, SotaniT, MatsuyamaH. Preparation of PVDF hollow fiber membrane from a ternary polymer/solvent/nonsolvent system via thermally induced phase separation (TIPS) method [J]. Sep Purif Technol, 2008, 63: 415-423

[10] QiuY-r, MatsuyamabH, GaoG-y, OuyangW, MiaoChang. Effects of diluent molecular weight on the performance of hydrophilic poly(vinyl butyral)/Pluronic F127 blend hollow fiber membrane via thermally induced phase separation [J]. J Membr Sci, 2009, 338: 128-134

[11] FuX-y, SotaniT, MatsuyamaH. Effect of membrane preparation method on the outer surface roughness of cellulose acetate butyrate hollow fiber membrane [J]. Desalination, 2008, 233: 10-18

[12] JiG L, ZhuL P, ZhuB K. Structure formation and characterization of PVDF hollow fiber membrane prepared via TIPS with diluent mixture [J]. J Membr Sci, 2008, 319: 264-270

[13] QiuY-r, OuyangWei. Rheological behavior of poly(vinyl butyral)/polyethylene glycol binary systems [J]. Mat Sci Eng C, 2012, 32: 167-171

[14] ShangM-x, MatsuyamaH, MakiT, TeramotoM, LloydD R. Preparation and characterization of poly(ethylene-co-vinyl alcohol) membranes via thermally induced liquid-liquid phase separation [J]. J Appl Polym Sci, 2003, 87: 853-860

[15] SmithP, LemstraP J. Ultra-high-strength polyethylene filaments by solution spinning/drawing [J]. J Mater Sci, 1980, 15(2): 505-514

[16] ChouW L, YangM C. Effect of take-up speed on physical properties and permeation performance of cellulose acetate hollow fibers [J]. J Membr Sci, 2005, 250: 259-267