scholarly journals Structure and Properties of PSf Hollow Fiber Membranes with Different Molecular Weight Hyperbranched Polyester Using Pentaerythritol as Core

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 383
Author(s):  
Min Liu ◽  
Long-Bao Zhao ◽  
Li-Yun Yu ◽  
Yong-Ming Wei ◽  
Zhen-Liang Xu
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Hollow Fiber ◽  
Pure Water ◽  
Esterification Reaction ◽  
Hollow Fiber Membranes ◽  
Water Contact ◽  
Molecular Weights ◽  
Hyperbranched Polyesters ◽  
Fiber Membranes

A homologous series of hyperbranched polyesters (HBPEs) was successfully synthesized via an esterification reaction of 2,2-bis(methylol)propionic acid (bis-MPA) with pentaerythritol. The molecular weights of the HBPEs were 2160, 2660, 4150 and 5840 g/mol, respectively. These HBPEs were used as additives to prepare polysulfone (PSf) hollow fiber membranes via non-solvent induced phase separation. The characteristic behaviors of the casting solution were investigated, as well as the morphologies, hydrophilicity and mechanical properties of the PSf membranes. The results showed that the initial viscosities of the casting solutions were increased, and the shear-thinning phenomenon became increasingly obvious. The demixing rate first increased and then decreased when increasing the HBPE molecular weight, and the turning point was 2660 g/mol. The PSf hollow fiber membranes with different molecular weights of HBPEs had a co-existing morphology of double finger-like and sponge-like structures. The starting pure water contact angle decreased obviously, and the mechanical properties improved.

scholarly journals Hydrophilic Dual Layer Hollow Fiber Membranes for Ultrafiltration

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 143
Author(s):  
Lara Grünig ◽  
Ulrich A. Handge ◽  
Joachim Koll ◽  
Oliver Gronwald ◽  
Martin Weber ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hollow Fiber ◽  
Triblock Copolymer ◽  
Pure Water ◽  
Vinyl Pyrrolidone ◽  
Scattering Data ◽  
Coupling Mechanism ◽  
Additive Concentration ◽  
Hollow Fiber Membranes ◽  
Fiber Membranes

In this study, a triblock copolymer was used as additive to fabricate new dual layer hollow fiber membranes with a hydrophilic active inner surface in order to improve their fouling resistance. The polymeric components of the solutions for membrane fabrication were poly(ether sulfone), poly(N-vinyl pyrrolidone), and the triblock copolymer. The additive consists of three blocks: a middle hydrophobic poly(ether sulfone) block and two outer hydrophilic alkyl poly(ethylene glycol) blocks. By varying the additive concentration in the solutions, it was possible to fabricate dual layer hollow fiber membranes that are characterized by a hydrophilic inner layer, a pure water permeance of over 1800 L/(m2 bar h) and a molecular weight cut-off of 100 kDa similar to commercial membranes. Contact angle and composition determination by XPS measurements revealed the hydrophilic character of the membranes, which improved with increasing additive concentration. Rheological, dynamic light scattering, transmission, and cloud point experiments elucidated the molecular interaction, precipitation, and spinning behavior of the solutions. The low-molecular weight additive reduces the solution viscosity and thus the average relaxation time. On the contrary, slow processes appear with increasing additive concentration in the scattering data. Furthermore, phase separation occurred at a lower non-solvent concentration and the precipitation time increased with increasing additive content. These effects revealed a coupling mechanism of the triblock copolymer with poly(N-vinyl pyrrolidone) in solution. The chosen process parameters as well as the additive solutions provide an easy and inexpensive way to create an antifouling protection layer in situ with established recipes of poly(ether sulfone) hollow fiber membranes. Therefore, the membranes are promising candidates for fast integration in the membrane industry.

scholarly journals Preparation and characterization of different geometrical shapes of multi-bore hollow fiber membranes and application in vacuum membrane distillation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Elham M. El-Zanati ◽  
Eman Farg ◽  
Esraa Taha ◽  
Ayman El-Guindi ◽  
Heba Abdallah
Keyword(s):  
Mechanical Properties ◽  
Flow Rate ◽  
Hollow Fiber ◽  
Amorphous Structure ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Hollow Fiber Membranes ◽  
Preparation Conditions ◽  
Geometrical Shapes ◽  
Fiber Membranes

Abstract Multi-bore hollow fiber membranes were prepared through phase inversion spinning process using new locally designed spinnerets of various geometrical shapes. The spun cylindrical-like, rectangular or ribbon-like, and triangular-like are prepared, dried, and characterized by scanning electronic microscope. Fibers of circular (seven, five, and four bores) shape, rectangular of five bores, and triangular of three bores were chosen to study the effect of both geometrical configuration and the number of bores on the amorphous structure and the mechanical properties of the membranes. Membrane geometry, surface amorphous, and bore arrangements are very sensitive to the operating conditions, especially the extrusion and drawing rates. Three polymeric blends of different compositions are used to prepare multi-bore hollow fiber membranes. This study revealed that the blend composition of PES 16%, PVP 2%, PEG 2%, diethylene glycol 2%, and NMP 78% gives excellent mechanical properties. Optimization of the preparation conditions also developed, where the dope flow rate, the bore flow rate, and the air gap were 1.14 cm3 s−1, 1.1 cm3 s−1, and 0 cm, respectively. Furthermore, this study proved that the circular arrangement has high mechanical strength. The prepared seven-MBHF membranes were applied in the membrane distillation process, a solution of 35 g/l NaCl was used to test the membrane performance, and the achieved flux and rejection were 28.32 L/m2 h and 98.9%, respectively. This performance demonstrated that the prepared membrane in this way is suitable to compete with conventional reverse osmosis technology that uses single track hollow fibers.

Structure Morphology of Polyethersulfone Hollow Fiber Membrane via Immersion Precipitation Phase Inversion Process

2012 ◽  
Vol 152-154 ◽  
pp. 574-578 ◽  
Author(s):  
Ping Lan ◽  
Wei Wang
Keyword(s):  
Hollow Fiber ◽  
Phase Inversion ◽  
Hollow Fiber Membrane ◽  
Pure Water ◽  
Water Flux ◽  
Additive Concentration ◽  
Hollow Fiber Membranes ◽  
Fiber Membrane ◽  
Fiber Membranes ◽  
And Performance

Polyethersulfone (PES) hollow fiber membranes have been widely used in many fields, such as ultrafiltration, microfiltration, reverse osmosis, liquid/liquid or liquid/solid separation, gas separation, hemodialysis, and so on. In this paper, the sheet PES hollow fiber membranes were prepared. The morphology and performance of membranes can be controlled. By studying the influence of the compositions and conditions on the morphology and performance of PES hollow fiber membrane, the relationship of morphology and performance of the membrane is acquired. The additives were used such as glycerol, BuOH and PEG. In addition, immerse phase inversion was used as membranes preparation method. The morphology of the membrane was controlled by changing kinds of additive, concentration of additive and so on. It was found that the membrane morphologies were changed by additive obviously. Porosity , pure water flux, scanning electron microscopy(SEM) were used to characterize the morphology and performance of the membranes.

PVDF hollow fiber membranes prepared from green diluent via thermally induced phase separation: Effect of PVDF molecular weight

2014 ◽  
Vol 471 ◽  
pp. 237-246 ◽  
Author(s):  
Naser Tavajohi Hassankiadeh ◽  
Zhaoliang Cui ◽  
Ji Hoon Kim ◽  
Dong Won Shin ◽  
Aldo Sanguineti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Hollow Fiber ◽  
Thermally Induced Phase Separation ◽  
Hollow Fiber Membranes ◽  
Separation Effect ◽  
Thermally Induced ◽  
Fiber Membranes

Preparation for PTFE Hollow Fiber Membranes Used in Water Treatment and Optimization for its Extrusion Process

2013 ◽  
Vol 750-752 ◽  
pp. 828-831 ◽  
Author(s):  
Chao Zhuang ◽  
Zhi Qing Luo ◽  
Wen Qing Chen
Keyword(s):  
Water Treatment ◽  
Hollow Fiber ◽  
Retention Rate ◽  
Pure Water ◽  
Water Flux ◽  
Chemical Properties ◽  
Hollow Fiber Membranes ◽  
High Fracture ◽  
Processing Methods ◽  
Fiber Membranes

For their excellent physical and chemical properties, PTFE hollow fiber membranes can be used in harsh environment of water treatment. But the membranes cannot be prepared by conventional methods, such as the melting processing methods and the dry-wet spinning processing methods, because of a high melting point of 327°C and chemical stability. In this paper a method of extrusion-stretching-sintering is used, and using this method we get the membranes with high fracture strength (10MPa) and high pure water flux (1500L/(m2*h)), also the retention rate of bovine serum albumin reaching 50%, which meets the laboratory microfiltration membrane requirements.

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