Fabrication and characterization of cellulose triacetate porous membranes by combined nonsolvent-thermally induced phase separation

Xing, Xiaoyan; Gu, Lin; Yu, Jin; Sun, Rui; Xie, Meng-Yun; Wu, Qingyun

doi:10.1007/s10570-019-02347-7

Cited by 15 publications

(9 citation statements)

References 46 publications

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“…Overall, we saw no significant difference among the membranes A–F, all of which showed a completely porous interconnected structure with a pore size of ∼100 nm or larger rather than the spherical structure seen in many other studies. 6 , 11 , 18 , 21 − 23 , 31 − 35 , 37 , 38 From Figures 3 and 4 , the cloud point is higher than the crystallization temperature in all systems. Therefore, interconnected structures were formed here due to the liquid phase separation.…”

Section: Resultsmentioning

confidence: 90%

“…At lower temperatures, there was another peak at around 27 °C due to the freezing of NPG. Similar phenomena were observed by Yu et al 11 and Xing et al 23 in the CTA/DMSO2/PEG400 polymer solution. Although the freezing point of DMSO 2 is 109 °C, only one crystallization peak was observed at around 45−50 °C in their studies.…”

Section: Phase Diagram Of Cellulosementioning

confidence: 99%

“…The water permeance was less than 150 L/(m 2 ·h·bar) even in the case of a soft and ductile membrane with 5 wt % CTA. In another study, 23 Xing et al prepared CTA flat-sheet UF membranes using N-TIPS, which combines the NIPS and TIPS methods. Although their approach produced a very porous bottom surface with a pore size of ∼1 μm, the structure on the outer surface was still dense.…”

Section: Introductionmentioning

confidence: 99%

“…Similar to the previous study, a low polymer concentration (8 wt %), a high bath temperature, and a high solvent content in the bath were used to obtain a porous membrane with a pore size of ∼50 nm. Notably, it is very difficult or impossible to obtain hollow fiber membranes using the approach described in the previous studies , mainly because of the low polymer concentration in the solution.…”

Section: Introductionmentioning

confidence: 99%

“…There have been considerable studies on preparing cellulose derivative membranes, but most of them focused on dense membranes made mainly using CDA and CAP, while porous CTA membranes were rarely reported. An extensive and comprehensive search of the literature revealed only two reports on fabricating CTA MF flat-sheet membranes. , Further, the conditions used in those studies were very challenging (e.g., very low polymer concentrations <8 wt %, special bath composition, and high bath temperature), which resulted in extremely low mechanical strengths. Especially, the preparation of a self-standing CTA MF hollow fiber membrane has not been reported.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Microfiltration Hollow Fiber Membranes from Cellulose Triacetate by Thermally Induced Phase Separation

et al. 2022

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For the first time, self-standing microfiltration (MF) hollow fiber membranes were prepared from cellulose triacetate (CTA) via the thermally induced phase separation (TIPS) method. The resultant membranes were compared with counterparts prepared from cellulose diacetate (CDA) and cellulose acetate propionate (CAP). Extensive solvent screening by considering the Hansen solubility parameters of the polymer and solvent, the polymer’s solubility at high temperature, solidification of the polymer solution at low temperature, viscosity, and processability of the polymeric solution, is the most challenging issue for cellulose membrane preparation. Different phase separation mechanisms were identified for CTA, CDA, and CAP polymer solutions prepared using the screened solvents for membrane preparation. CTA solutions in binary organic solvents possessed the appropriate properties for membrane preparation via liquid–liquid phase separation, followed by a solid–liquid phase separation (polymer crystallization) mechanism. For the prepared CTA hollow fiber membranes, the maximum stress was 3–5 times higher than those of the CDA and CAP membranes. The temperature gap between the cloud point and crystallization onset in the polymer solution plays a crucial role in membrane formation. All of the CTA, CDA, and CAP membranes had a very porous bulk structure with a pore size of ∼100 nm or larger, as well as pores several hundred nanometers in size at the inner surface. Using an air gap distance of 0 mm, the appropriate organic solvents mixed in an optimized ratio, and a solvent for cellulose derivatives as the quench bath media, it was possible to obtain a CTA MF hollow fiber membrane with high pure water permeance and notably high rejection of 100 nm silica nanoparticles. It is expected that these membranes can play a great role in pharmaceutical separation.

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