Influence of the coagulation-bath temperature on the phase-separation process of poly(vinylidene fluoride)-graft-poly(N-isopropylacrylamide) solutions and membrane structures

Poly(vinylidene fluoride)(PVDF), poly(vinyl chloride)(PVC), and poly(methyl methacrylate)(PMMA) were used as the main materials in the preparation of novel blend five-hole membrane. Dimethylacetamide (DMAC) and polyvinyl pyrrolidone (PVP) were used as solvent and additive, respectively. The effect of some external coagulation conditions on the property of five-hole membrane was studied. The external coagulation conditions investigated in the work were the coagulation temperature and the DMAC content in coagulation bath. The result showed that the flux increased along with the increase of coagulation bath temperature and could reach the max at 35°C, then decreased gradually. The effect of the DMAC content in coagulation bath on flux is very similar to that of the temperature. The cross-sectional structures were examined by scanning electron microscopy.

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A facile non-solvent induced phase separation process for preparation of highly porous polybenzimidazole separator for lithium metal battery application

Scientific Reports ◽

10.1038/s41598-019-55865-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Jiaying Wang ◽

Yang He ◽

Quan Wu ◽

Yunfeng Zhang ◽

Zhiyuan Li ◽

...

Keyword(s):

Phase Separation ◽

Polymer Electrolyte ◽

Density Functional ◽

Ethylene Carbonate ◽

Rate Capability ◽

Separation Process ◽

Coagulation Bath ◽

Electrolyte Uptake ◽

Phase Separation Process ◽

Highly Porous

AbstractThe drawbacks of low porosity, inferior electrolyte wettability, low thermal dimensional stability and permissive lithium dendrite growth of the conventional microporous polyolefin-based separators hinder their widely application in the high power density and safe Lithium ion batteries. Herein, highly porous polybenzimidazole-based separator is prepared by a facile non-solvent induced phase separation process (NIPS) using water, ethanol, chloroform and ethyl acetate as the coagulation bath solvent, respectively. It was found that the ethanol is suitable to fabricate uniform morphology macroporous separator with the porosity of 92%, electrolyte uptake of 594 wt.%, and strong mechanical strength of 15.9 MPa. In addition, the experimental tests (electrochemical analysis and XPS test) and density functional theory calculation suggest that the electron-rich imidazole ring of polybenzimidazle can enhance Li+ mobility electrostatic attraction interaction while the block the PF6− mobility via electrostatic repulsion interaction. Therefore, high Li+ transference number of 0.76 was obtained for the neat polybenzimidazole-based polymer electrolyte. As a proof of concept, the Li/LiFePO4 cell with the polybenzimidazole-based polymer electrolyte/1.0 M LiPF6− ethylene carbonate/dimethyl carbonate (v:v = 1:1) electrolyte exhibits excellent rate capability of >100 mAh g−1 at 6 C (1 C = 170 mA g−1) and superior cycle stability of 1000 cycles.

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Preparation of hydrophilic modified polyvinylidene fluoride (PVDF) ultrafiltration membranes by polymer/non-solvent co-induced phase separation: effect of coagulation bath temperature

Journal of Polymer Engineering ◽

10.1515/polyeng-2021-0245 ◽

2022 ◽

Vol 0 (0) ◽

Author(s):

Xiaoming Zhang ◽

Qingchen Lu ◽

Nana Li

Keyword(s):

Phase Separation ◽

Membrane Fouling ◽

Membrane Structure ◽

Polyvinylidene Fluoride ◽

Membrane Surface ◽

Pure Water ◽

Bath Temperature ◽

Coagulation Bath ◽

Separation Performance ◽

Coagulation Bath Temperature

Abstract Membrane separation technology is widely used in wastewater purification, but the issue of membrane fouling could not be ignored. Hydrophilic modification is an effective method to reduce membrane fouling. Therefore, in this work, a hydrophilic modified polyvinylidene fluoride (PVDF) ultrafiltration membrane was prepared by polymer/non-solvent co-induced phase separation, and the effect of coagulation bath temperature on the membrane structure and performance was systematically investigated based on the previous study. With the increased of the coagulation bath temperature, the phase separation process changed from delayed to instantaneous, and the membrane surface changed from porous to dense, while the macropore structures and sponge-like pores appeared on the cross-section. Meanwhile, the pure water flux decreased from 229.3 L/(m2·h) to 2.08 L/(m2·h), the protein rejection rate increased from 83.87% to 100%, and the surface water contact angle increased from 63° to 90°. Thus, excessively high coagulation bath temperature adversely affected the permeate and separation performance, as well as antifouling performance of the membrane. This study enriched the research for preparing separation membranes by polymer/non-solvent co-induced phase separation and provided a practical and theoretical reference for controlling the membrane structure and properties by changing the coagulation bath temperature.

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Effects of Coagulation-Bath Temperature on the Formation Process of PVDF-g-PNIPAAm/poly(NIPAAm-co-AAc-L-Phe) Membrane

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.713-715.2681 ◽

2015 ◽

Vol 713-715 ◽

pp. 2681-2684

Author(s):

Xiao Tong Liang ◽

Meng Xin Gu ◽

Jin Ling Li ◽

Xue Wang ◽

Yi Ping Zhao ◽

...

Keyword(s):

Formation Process ◽

Vinylidene Fluoride ◽

Bath Temperature ◽

Time Domain Reflectometry ◽

Coagulation Bath ◽

Racemic Mixture ◽

Inversion Method ◽

Membrane Formation ◽

Ultrasonic Time ◽

Coagulation Bath Temperature

In this work, poly (vinylidene fluoride)-graft-poly (N-isopropylacrylamide) (PVDF-g-PNIPAAm) thermo-sensitive polymer and poly (NIPAAm-co-AAc-L-Phe) chiral micro-gels were synthesized firstly. A chiral thermo-sensitive membrane for phenylalanine separation of the racemic mixture was prepared by phase inversion method with the blend of poly (NIPAAm-co-AAc-L-Phe) and PVDF-g-PNIPAAm. The blend membrane formation mechanism of the casting solutions in water bath thermodynamics at different temperatures and the process of membrane formation were investigated via cloud point determination and ultrasonic time-domain reflectometry (UTDR). The results showed that the inversion between hydrophilicity and hydrophobicity of PNIPAAm contributed to the membrane formation process. From the time needed in membrane forming recorded by ultrasonic signal spectra, it can be found that the speed for solidification was increased when the coagulation-bath temperature was higher than 30°C.

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