scholarly journals Colorless and Transparent Polyimide Microporous Film with Excellent Physicochemical Property

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1298
Author(s):  
Jong Won Kim ◽  
Seon Ju Lee ◽  
Moon Young Choi ◽  
Jin-Hae Chang
Keyword(s):  
Pore Size ◽  
Porous Membrane ◽  
Amic Acid ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Thermal Stabilities ◽  
Blend Films ◽  
Hydrogen Bonding Interactions ◽  
Heat Treated ◽  
Microporous Film

4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) as a dianhydride and bis(3-aminophenyl) sulfone (APS) and bis(3-amino-4-hydroxyphenyl) sulfone (APS-OH) as diamines were used to synthesize two types of poly(amic acid) (PAA). Varying amounts (0–5.0 wt%) of water-soluble poly(vinyl alcohol) (PVA) were mixed with PAA, and the resulting blend was heat-treated at different stages to obtain the colorless and transparent polyimide (CPI) blend films. The synthesized blended film completely removed water-soluble PVA in water. The possibility as a porous membrane according to the pore size varied according to the amount of PVA was investigated. The dispersibility and compatibility of CPI containing APS-OH monomer were higher than those of the APS monomer. This could be attributed to the hydrogen-bonding interactions between the CPI main chains and PVA. Scanning electron microscopy was conducted to characterize the material. The results revealed that the pore size of the CPI blend film increased as the PVA concentration increased. It was confirmed that uniform pores of μm-size were observed in CPI. The thermal stabilities, morphologies, optical properties, and solubilities of two CPIs obtained using APS and APS-OH monomers were investigated and their properties were compared with each other.

scholarly journals Syntheses of Colorless and Transparent Polyimide Membranes for Microfiltration

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1610
Author(s):  
Jong Won Kim ◽  
Jin-Hae Chang
Keyword(s):  
Heat Treatment ◽  
Composite Material ◽  
Composite Films ◽  
Porous Membrane ◽  
Amic Acid ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Water Soluble Polymer

Herein, poly(amic acid) (PAA) was synthesized using 4,4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) as a dianhydride and 2,2-bis(3-aminophenyl)hexafluoropropane (6FAm) and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAm-OH) as diamines. Poly(vinyl alcohol) (PVA) at various contents (0–5.0 wt%) was blended with PAA to prepare a composite material. Then, colorless and transparent polyimide (CPI) composite films were prepared by applying various stages of heat treatment using the PAA/PVA blend film as a precursor. These film-type composites were immersed in water to completely dissolve PVA, a water-soluble polymer, and their pore sizes were investigated to determine their potential as a porous membrane. According to the results of scanning electronic microscopy (SEM), as the concentration of PVA increased from 0 to 5.0 wt% in the CPI/PVA composite films, the size of the pores resulting from the dissolution of water-soluble PVA increased. Further, the micrometer-sized pores were uniformly dispersed in the CPI films. The thermal properties, morphology, and optical transparency of the two types of CPI membranes synthesized using 6FAm and 6FAm-OH monomers were examined and compared.

Application of the ceramic membrane with hydrophobic skin layer to separation of activated sludge

1997 ◽  
Vol 35 (8) ◽  
pp. 137-144 ◽  
Author(s):  
Tsuyoshi Nomura ◽  
Takao Fujii ◽  
Motoyuki Suzuki
Keyword(s):  
Activated Sludge ◽  
Pore Size ◽  
Ceramic Membrane ◽  
Membrane Separation ◽  
Porous Ceramic ◽  
Porous Membrane ◽  
Skin Layer ◽  
Gas Permeation ◽  
Wide Range ◽  
Cake Layer

Porous membrane of poly(tetrafluoroethylene) (PTFE) was formed on the surface of porous ceramic tubes by means of heat treatment of the PTFE particles deposit layer prepared by filtering PTFE microparticles emulsified in aqueous phase. By means of inert gas permeation, pore size was determined and compared with scanning electron micrograph observation. Also rejection measurement of aqueous dextran solutions of wide range of molecular weights showed consistent results regarding the pore size. Since the membrane prepared by this method is stable and has unique features derived from PTFE, it is expected that the membrane has interesting applications in the field of water treatment. Membrane separation of activated sludge by this composite membrane and original ceramics membrane showed that the PTFE membrane gives better detachability of the cake layer formed on the membrane. This might be due to the hydrophobic nature of the PTFE skin layer.

scholarly journals Self-Healing Polymer-Clay Hybrids by Facile Complexation of a Waterborne Polymer with a Clay

2021 ◽  
Author(s):  
Aranee Pleng Teepakakorn ◽  
Makoto Ogawa
Keyword(s):  
Vinyl Alcohol ◽  
Aqueous Media ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Self Healing ◽  
Soluble Polymer ◽  
Water Soluble Polymer ◽  
Smectite Clay

Water-induced self-healing materials were prepared by the hybridization of a water-soluble polymer, poly(vinyl alcohol), with a smectite clay by mixing in an aqueous media and subsequent casting. Without using chemical...

Effect of Cobalt Stearate and Vegetable Oil on Uv and Biodegradation of Linear Low-Density Poly(Ethylene)-Poly(Vinyl Alcohol) Blends

2011 ◽  
Vol 2 (4) ◽  
pp. 131-148 ◽  
Author(s):  
Francis Vidya ◽  
Subin S. Raghul ◽  
Sarita G Bhat ◽  
Eby Thomas Thachil
Keyword(s):  
Vegetable Oil ◽  
Vinyl Alcohol ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Low Density ◽  
Compression Moulding ◽  
Melt Mixing ◽  
Degradation Behaviour ◽  
Moulding Process ◽  
Poly Ethylene

The main objective of this study was to enhance the rate of UV and biodegradation of polyethylene by incorporating biodegradable materials and prooxidants. Prooxidants such as transition metal complexes are capable of initiating photooxidation and polymer chain cleavage, rendering the product more susceptible to biodegradation. In this work, the effect of (1) a metallic photoinitiator, cobalt stearate, and (2) different combinations of cobalt stearate and vegetable oil on the photooxidative degradation of linear low-density poly(ethylene)-poly(vinyl alcohol) (LLDPE/PVA) blend films has been investigated. For this, film-grade LLDPE was blended with different proportions of PVA. PVA is widely used in the industrial field, and recently it has attracted increasing attention as a water-soluble biodegradable polymer. Cobalt stearate and vegetable oil were added to the blends as prooxidants. The blends were prepared by melt mixing in a Thermo HAAKE Polylab system. Thin films containing these additives were prepared by a subsequent compression moulding process. The effect of UV exposure on LLDPE/PVA films in the presence as well as absence of these additives was investigated. Tensile properties, FTIR spectra, and scanning electron microscopy (SEM) were employed to investigate the degradation behaviour. It was found

Pore Size Distribution and Blend Composition Affect In Vitro Prevascularized Bone Matrix Formation on Poly(Vinyl Alcohol)/Gelatin Sponges

2017 ◽  
Vol 302 (11) ◽  
pp. 1700300 ◽  
Author(s):  
Jose Gustavo De la Ossa ◽  
Luisa Trombi ◽  
Delfo D'Alessandro ◽  
Maria Beatrice Coltelli ◽  
Lorenzo Pio Serino ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Vinyl Alcohol ◽  
Bone Matrix ◽  
Poly Vinyl Alcohol ◽  
Blend Composition

scholarly journals Electrospinning of Cellulose Nanocrystal-Filled Poly (Vinyl Alcohol) Solutions: Material Property Assessment

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 805 ◽  
Author(s):  
J. Elliott Sanders ◽  
Yousoo Han ◽  
Todd S. Rushing ◽  
Douglas J. Gardner
Keyword(s):  
Vinyl Alcohol ◽  
Fiber Diameter ◽  
Morphological Structure ◽  
Poly Vinyl Alcohol ◽  
Oh Groups ◽  
Heat Treated ◽  
Property Assessment ◽  
Vinyl Group ◽  
Random Composite ◽  
Scanning Electron

Poly (vinyl alcohol) (PVA) and cellulose nanocrystals (CNC) random composite mats were prepared using the electrospinning method. PVA/CNC mats were reinforced with weight concentrations of 0, 20 and 50% CNC (w/w) relative to PVA. Scanning electron microscopy was used to measure the fiber diameter, which ranged from 377 to 416 nm. Thermogravimetric analysis (TGA) confirmed the presence of CNC fibers in the mat fibers which were not visible by scanning electron microscope (SEM). Mechanical testing was conducted using ASTM D 638 on each sample group at 10 mm min−1. Neat PVA and PVA/CNC mats were heat treated at 170 °C for 2h hours, and the morphological structure was maintained with some fiber diameter reduction. Mechanical property results after heat treatment showed a decrease in tensile strength, an increase in tensile stiffness and a decrease in strain to yield (%). This effect was attributable to enhanced diffusion bonding of the mat fiber intersections. The CNC fibers also increased mat stiffness, and reduced strain to yield in non-treated mats. The use of CNCs show potential for compounding into bulk polymer composites as a reinforcement filler, and also show promise for chemical crosslinking attributable to the –OH groups on both the PVA, in addition to esterification of the vinyl group, and CNC.

Sign in / Sign up

Export Citation Format

Share Document