Vitrification phenomena in polysulfone/NMP/water system

Kim, Je Young; Kim, Young Duk; Kanamori, Toshiyuki; Lee, Hwan Kwang; Baik, Ki‐Jun; Kim, Sung Chul

doi:10.1002/(sici)1097-4628(19990118)71:3<431::aid-app9>3.3.co;2-u

Cited by 9 publications

(21 citation statements)

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“…Consequently, the nascent structure formed after the onset of phase separation should not be regarded as static, since structure‐forming effects can result from a steady mass transfer until solidification is reached . If a critical viscosity is reached, the polymer solution turns into a gel state and solidifies, as coalescence and other coarsening mechanisms are no longer possible …”

Section: Introductionmentioning

confidence: 99%

Influences of different preparation variables on polymeric membrane formation via nonsolvent induced phase separation

Kahrs

Gühlstorf

Schwellenbach

2019

J of Applied Polymer Sci

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This work presents a comparative study on the formation of polyethersulfone ultrafiltration membranes via nonsolventinduced phase separation (NIPS) in two different solvent systems. N-methyl-2-pyrrolidone was chosen as conventional solvent and 2-pyrrolidone as a greener alternative. The overall objective was to obtain a mechanistic clarification of the membrane formation process in dependence of the most important controlling parameters. By performing different series of experiments, it was possible to determine the differences between the two solvents regarding the effects of variations in nonsolvent additives, polymer concentration, and precipitation conditions. It was found that a raising concentration of several nonsolvents, the increase of the polymer concentration and changes in the precipitation conditions can suppress the formation of macrovoids, regardless of the applied solvent. In contrast, differences were observed with regard to the performance of the membrane prototypes. This study improves the understanding of membrane formation via NIPS and identifies the effects of different variables. It shows that the choice of the solvent is essential for the dominating formation mechanisms and therefore for the resulting membrane features. It also proves that green solvents can substitute hazardous solvents if the influencing variables are well-understood in order to control them for obtaining desired membrane properties.

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Section: Introductionmentioning

confidence: 99%

Influences of different preparation variables on polymeric membrane formation via nonsolvent induced phase separation

Kahrs

Gühlstorf

Schwellenbach

2019

J of Applied Polymer Sci

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“…As the polymer solution film immersed into a coagulation bath through this process, it undergoes phase separation into a polymer rich phase and a polymer lean phase. The phase separation would be continued until the polymer‐rich phase is solidified and the membrane structure is formed . It has been proposed by different researchers that the gelation is the main mechanism leading to skin formation through this technique by suppressing L‐L demixing due to kinetic hindering caused by the high viscosity of a gelled polymer solution in the skin of the membrane .…”

Section: Gelation Mechanismmentioning

confidence: 99%

“…To achieve a better control on the structures of the preferable membrane, well knowledge of the gelation and vitrification mechanisms of a particular system is essential. Thermodynamic investigations regarding study of polymer dissolution and gelation behavior in membrane formation systems has been of interests for different authors throughout the years . However, as different mechanisms affect thermoreversible gelation behavior of casting solutions more comprehensive studies should be done for well thermodynamic description of a ternary membrane fabrication system and how it affects membrane structure with emphasis on demixing and gelation behavior.…”

Section: Introductionmentioning

confidence: 99%

“…Li et al investigated the gelation and demixing behavior of PSF and poly(ether sulfone) (PES) amorphous polymers in a mixture of different solvents and water as nonsolvent. Kim et al studied the vitrification phenomena in the ternary system of PSF/N‐methyl‐2‐pyrrolidinone (NMP)/water using differential scanning calorimeter (DSC) measurements at different compositions. The related vitrification line was determined and related mechanisms were discussed.…”

Section: Introductionmentioning

confidence: 99%

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A new perspective and comparative study on demixing and gelation behavior of cellulose acetate, cellulose acetate propionate and cellulose acetate butyrate ternary solutions

Okhovat

Karimi

Ashtiani

2017

Polymer Engineering & Sci

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Cellulose acetate (CA), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB) were fabricated as membrane via nonsolvent induced phase separation process. N,N‐Dimethylformamide (DMF) and N,N‐Dimethylacetamide (DMAc) as solvents and water as nonsolvent were employed. Ternary phase diagrams for all six ternary systems were constructed using Flory‐Huggins theory. In this way, cloud points as well as Berghman's points were determined. Modulus of polymers steepened in various concentration of solvent/nonsolvent mixtures were measured to find the weight fraction of polymer (wp) in which vitrification takes place. WP values for CA, CAP, and CAB were obtained 0.59, 0.67, and 0.74 in presence of DMF while those were 0.69, 0.74, and 0.84 in presence of DMAc; whereas glass transition temperatures (Tg) for three polymers were determined 180°C, 142°C, and 101°C correspondingly. Pure water flux for CA, CAP, and CAB membrane increased from 75.7 to 83.4 and 290.3 and from 109.6 to 116.1 and 400.3 L/m2 h bar when DMF and DMAc were used as solvents, respectively. Results revealed that as Tg of polymer decreases, the membrane structure vitrifies at higher polymer concentration with more porous structure, bigger pores, higher permeate flux followed by decrease in mechanical strength. POLYM. ENG. SCI., 58:1135–1145, 2018. © 2017 Society of Plastics Engineers

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“…In addition, as shown in Tables 1 and 2 Increasing of the solvent into the coagulation bath is more complex for CH 4 and N 2 gases. In the first case, the solvent tends to increase surface defects that causes the increase in the permeation of CH 4 [20,21]. Additionally, solvent causes delayed demixing which decreases highly the number of finger-like voids and eventually tends to decrease the permeances of gas molecules.…”

Section: Effect Of the Solvent Content Of The Coagulation Bathmentioning

confidence: 99%

Effect of Synthesis Parameters on Structural Characteristics of Polysulfone Membrane and its Gas Separation Properties

Mansoori

Pakizeh²,

Chenar³

2011

J Membra Sci Technol

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Vitrification phenomena in polysulfone/NMP/water system

Cited by 9 publications

References 0 publications

Influences of different preparation variables on polymeric membrane formation via nonsolvent induced phase separation

Influences of different preparation variables on polymeric membrane formation via nonsolvent induced phase separation

A new perspective and comparative study on demixing and gelation behavior of cellulose acetate, cellulose acetate propionate and cellulose acetate butyrate ternary solutions

Effect of Synthesis Parameters on Structural Characteristics of Polysulfone Membrane and its Gas Separation Properties

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