Gas Separation Membranes Derived from High-Performance Immiscible Polymer Blends Compatibilized with Small Molecules.

Science.gov (United States)

Panapitiya, Nimanka P; Wijenayake, Sumudu N; Nguyen, Do D; Huang, Yu; Musselman, Inga H; Balkus, Kenneth J; Ferraris, John P

2015-08-26

An immiscible polymer blend comprised of high-performance copolyimide 6FDA-DAM:DABA(3:2) (6FDD) and polybenzimidazole (PBI) was compatibilized using 2-methylimidazole (2-MI), a commercially available small molecule. Membranes were fabricated from blends of 6FDD:PBI (50:50) with and without 2-MI for H2/CO2 separations. The membranes demonstrated a matrix-droplet type microstructure as evident with scanning electron microscopy (SEM) imaging where 6FDD is the dispersed phase and PBI is the continuous phase. In addition, membranes with 2-MI demonstrated a uniform microstructure as observed by smaller and more uniformly dispersed 6FDD domains in contrast to 6FDD:PBI (50:50) blend membranes without 2-MI. This compatibilization effect of 2-MI was attributed to interfacial localization of 2-MI that lowers the interfacial energy similar to a surfactant. Upon the incorporation of 2-MI, the H2/CO2 selectivity improved remarkably, compared to the pure blend, and surpassed the Robeson's upper bound. To our knowledge, this is the first report of the use of a small molecule to compatibilize a high-performance immiscible polymer blend. This approach could afford a novel class of membranes in which immiscible polymer blends can be compatibilized in an economical and convenient fashion.

Pervaporation of alcohol-toluene mixtures through polymer blend membranes of poly(acrylic acid) and poly(vinyl alcohol)

NARCIS (Netherlands)

Park, H.C.; Park, H.; Meertens, R.M.; Meertens, R.M.; Mulder, M.H.V.; Smolders, C.A.; Smolders, C.A.

1994-01-01

Homogeneous membranes were prepared by blending poly(acrylic acid) with poly(vinyl alcohol). These blend membranes were evaluated for the selective separation of alcohols from toluene by pervaporation. The flux and selectivity of the membranes were determined both as a function of the blend

[Preparation and physicochemical property of carboxymethyl-chitosan/hyaluronic acid poly(vinyl alcohol) blend membrane].

Science.gov (United States)

Liu, Wen; Li, Shuning; Chang, Jing; Han, Baoqin; Liu, Wanshun

2009-08-01

To prepare carboxymethyl-chitosan/hyaluronic acid/poly(vinyl alcohol) (CHP) blend membrane, evaluate its physicochemical properties and intraocular biocompatibility and to investigate its feasibility to be applied to glaucoma filtering surgery. CHP blend membrane was prepared using solution casting method after blending carboxymethyl-chitosan, HA and poly(vinyl alcohol) in a proportion of 5 : 4 : 1 (M/M). Its water absorption rate, swelling rate, permeability, and mechanical properties were detected. Subconjunctival fibroblasts separated from subconjunctival tissue of New Zealand white rabbits were cultured, and the cells at passage 4 were cultured on cell culture plate with or without the CHP blend membrane, serving as the experimental group and the control group, respectively. Effect of the CHP blend membrane on the subconjunctival fibroblasts was tested by MTT method 24, 48, and 72 hours after culture. Six New Zealand white rabbits were randomly divided into two groups (n = 3 rabbits per group), and the CHP blend membrane and SK gel were implanted into the rabbits' subconjunctival space and anterior chamber in the experimental group and the control group, respectively. Slit lamp observation and binocular reaction record were conducted 1, 3, 5, 9, 11, 20, 30, 45, and 60 days after operation. Corneal tissue harvested from the experimental group was observed using scanning electron microscope 15 days after operation to study ophthalmic biocompatibility and biodegradability. The water absorption rate and the swelling rate of the CHP blend membrane was 83.8% +/- 1.3% and 3.59 +/- 0.50, respectively. The tensile strength of the dry and the wet CHP blend membrane was (20.59 +/- 1.73) and (0.51 +/- 0.13) MPa, respectively. The breaking elongation rate of the dry and the wet CHP blend membrane was 10.69% +/- 1.16% and 53.15% +/- 2.46%, respectively. The CHP blend membrane had good permeability to NaCl and L-tyrosine. Absorbance (A) value of the experimental group 24, 48

FTIR, XRD and DSC studies of nanochitosan, cellulose acetate and polyethylene glycol blend ultrafiltration membranes.

Science.gov (United States)

Vinodhini, P Angelin; K, Sangeetha; Thandapani, Gomathi; P N, Sudha; Jayachandran, Venkatesan; Sukumaran, Anil

2017-11-01

In the present work, a series of novel nanochitosan/cellulose acetate/polyethylene glycol (NCS/CA/PEG) blend flat sheet membranes were fabricated in different ratios (1:1:1, 1:1:2, 2:1:1, 2:1:2, 1:2:1, 2:2:1) in a polar solvent of N,N'-dimethylformamide (DMF) using the most popular phase inversion method. Nanochitosan was prepared by the ionotropic gelation method and its average particle size has been analyzed using Dynamic Light Scattering (DLS) method. The effect of blending of the three polymers was investigated using FTIR and XRD studies. FTIR results confirmed the formation of well-blended membranes and the XRD analysis revealed enhanced amorphous nature of the membrane ratio 2:1:2. DSC study was conducted to find out the thermal behavior of the blend membranes and the results clearly indicated good thermal stability and single glass transition temperature (T g ) of all the prepared membranes. Asymmetric nature and rough surface morphology was confirmed using SEM analysis. From the results it was evident that the blending of the polymers with higher concentration of nanochitosan can alter the nature of the resulting membranes to a greater extent and thus amorphous membranes were obtained with good miscibility and compatibility. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved permeation performance and fouling-resistance of Poly(vinyl chloride/Polycarbonate blend membrane with added Pluronic F127

Directory of Open Access Journals (Sweden)

Supateekan Pacharasakoolchai

2014-04-01

Full Text Available The aim of this work was to prepare and characterize poly(vinyl chloride (PVC/polycarbonate (PC blend membranes for use in ultrafiltration. Pluronic F127 was used as an additive to modify the membrane surface of the PVC/PC blended membranes. The PVC/PC blend membrane was first prepared using the phase inversion method from a casting solution of PVC with small amount of PC in N-methylpyrrolidone (NMP and water as the non-solvent. The morphologies structure and properties, such as tensile strength, water flux, and bovine serum albumin (BSA rejection of the blend membrane were studied. Increased amounts of PC resulted in an increase in the water flux and ability to reject protein. A concentration of 0.75 wt% PC provided the best improvement in tensile strength of blend membrane. Addition of different amounts of pluronic F127 to the casting solution of PVC/PC with a PC concentration of 0.75 wt% resulted in a decrease in the water contact angle that demonstrated the improvement of hydrophilicity of blend membrane. Scanning electron microscopy photographs showed that the modified PVC/PC membranes had a bigger pore volume in the porous sub-layer compared to the PVC/PC control membrane. The PVC/PC membrane with added Pluronic F127 exhibited a much higher flux and rejection of BSA in a protein filtration experiment than the PVC/PC membrane. An increase in flux recovery ratio of PVC/PC/pluronic 127 blend membrane indicated that the modified membranes could reduce membrane fouling useful for ultrafiltration.

Preparation of Cu{sub 2}O nanowire-blended polysulfone ultrafiltration membrane with improved stability and antimicrobial activity

Energy Technology Data Exchange (ETDEWEB)

Xu, Zehai; Ye, Shuaiju; Fan, Zheng; Ren, Fanghua; Gao, Congjie [Zhejiang University of Technology, Institute of Oceanic and Environmental Chemical Engineering, College of Chemical Engineering and Material Science and College of Ocean, and State Key Lab Breeding Base of Green Chemical Synthesis Technology and Zhejiang Collaborative Innovation Center of Membrane Separation and Water Treatment (China); Li, Qingbiao; Li, Guoqing [Quanzhou Normal University, College of Chemistry and Life Science (China); Zhang, Guoliang, E-mail: membrane86571@163.com, E-mail: guoliangz@zjut.edu.cn [Zhejiang University of Technology, Institute of Oceanic and Environmental Chemical Engineering, College of Chemical Engineering and Material Science and College of Ocean, and State Key Lab Breeding Base of Green Chemical Synthesis Technology and Zhejiang Collaborative Innovation Center of Membrane Separation and Water Treatment (China)

2015-10-15

Polysulfone (PSF) membranes have been widely applied in water and wastewater treatment, food-processing and biomedical fields. In this study, we report the preparation of modified PSF membranes by blending PSF with Cu{sub 2}O nanowires (NWs) to improve their stability and antifouling activity. Synthesis of novel Cu{sub 2}O NWs/PSF-blended ultrafiltration membrane was achieved via phase inversion method by dispersing one-dimensional Cu{sub 2}O nanowires in PSF casting solutions. Various techniques such as XRD, SEM, TEM, and EDS were applied to characterize and investigate the properties of nanowires and membranes. The introduced Cu{sub 2}O nanowires can firmly be restricted into micropores of PSF membranes, and therefore, they can effectively prevent the serious leaking problem of inorganic substances in separation process. The blended PSF membranes also provided enhanced antimicrobial activity and superior permeation property compared to pure PSF membrane. The overall work can not only provide a new way for preparation of novel blended membranes with multidimensional nanomaterials, but can also be beneficial to solve the annoying problem of biofouling.

Characteristics of PVdF copolymer/Nafion blend membrane for direct methanol fuel cell (DMFC)

International Nuclear Information System (INIS)

Cho, Ki-Yun; Eom, Ji-Yong; Jung, Ho-Young; Choi, Nam-Soon; Lee, Yong Min; Park, Jung-Ki; Choi, Jong-Ho; Park, Kyung-Won; Sung, Yung-Eun

2004-01-01

For direct methanol fuel cell, blends of vinylidene fluoride-hexafluoropropylene copolymer (P(VdF-co-HFP)) and Nafion were prepared the different equivalent weight of Nafion. The investigations of the blend morphology were performed by means of permeability test, uptake measurement, differential-scanning calorimetry (DSC), and scanning electron microscopy. In the blend membranes, many pores were created as the content of Nafion in blend increased. Then, the methanol uptake was sharply increased. But the methanol permeability was not sharply increased because the methanol permeation through blend membranes is diffusion-controlled process. The methanol permeability of N10 (low equivalent weight) series was similar to that of N11 series (high equivalent weight). The proton conductivity of N10 series was around one and a half times higher than that of N11 series. The cell performance of the blend was much enhanced when the equivalent weight of Nafion was 1000

Effects of Electron Beam Irradiation on Binary Polyamide-6 Blends with Metallocene Copolymers

International Nuclear Information System (INIS)

Rosales, C.

2006-01-01

A versatile way to produce new materials with high Izod impact strength and reduced heat deformations is the irradiation of compatibilized blends. The effect of electron beam irradiation and different types of dispersed phase grafted copolymers on thermal and mechanical properties, and SEM morphology of polyamide-6 (PA-6) blends were investigated. Two metallocene copolymers (mEPDM and mPOE) grafted in-situ with maleic anhydride and two commercial maleated copolymers (EPDM-g-MA and mEPR-g-MA) were employed in binary blends with PA6 as matrix. The blends were prepared by extrusion with a composition of 80 wt. % of PA-6. The influence of the radical or functional groups generated in the grafting and the irradiation processes (25, 50, 100 and 200 kGy) was found by ATR-FTIR. The blends exhibited the characteristic thermal behavior of immiscible systems. All compatibilizers employed influenced the melting and crystallization behavior of the blend components without irradiation and an improvement in interface adhesion was clearly observed by SEM micrographs. The sizes of the dispersed phase in the non-irradiated reactive blends were in agreement with the viscosity ratios of the blend components. High toughness materials were obtained with ethylene-polypropylene-diene (mEPDM) grafted copolymers without significant variations in their thermal properties and Izod impact strength at room temperature and -30 degree with the irradiation doses. However, the toughness of the blends with grafted metallocene polyethylenes was affected by the irradiation doses employed. Therefore, the gel content and tensile properties of the samples depended on the chain scission, crosslinking and/or grafting reactions of the blend components

Novel modified poly vinyl chloride blend membranes for removal of heavy metals from mixed ion feed sample

Energy Technology Data Exchange (ETDEWEB)

Nayak, Vignesh; Jyothi, M.S. [Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Kanakapura Ramanagaram, Bangalore, 562112 (India); Balakrishna, R. Geetha, E-mail: br.geetha@jainuniversity.ac.in [Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Kanakapura Ramanagaram, Bangalore, 562112 (India); Padaki, Mahesh, E-mail: sp.mahesh@jainuniversity.ac.in [Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Kanakapura Ramanagaram, Bangalore, 562112 (India); National University of Science and Technology “MISIS”, Moscow, 119049 (Russian Federation); Deon, Sebastien [Institut UTINAM, UMR CNRS 6213, Université de Bourgogne-Franche-Comté,16 route de Gray, Besançon Cedex 25030 (France)

2017-06-05

Highlights: • Work reports the novel modification of poly vinyl chloride (PVC) using newly developed method. • Blend membranes were prepared using modified PVC and polysulfone in different compositions. • The prepared blend membranes were used for separation of different heavy metal ions. • The blend membranes showed improved rejection of heavy metal ions in comparison to Commercial NF 270 membrane. - Abstract: Herein, an attempt has been made to prepare a novel membrane with good efficiency for removal of heavy metal ions namely lead (Pb), cadmium (Cd) and chromium (Cr). 4-amino benzoic acid (ABA) was covalently grafted onto the poly vinyl chloride (PVC) backbone by C−N bond to enhance the hydrophilicity. {sup 1}H NMR and ATR-IR spectroscopy analysis confirmed the chemical modification of PVC. Further the modified polymer was blended in different compositions with polysulfone (PSf) for optimization. Morphological changes that occurred in blend membranes, due to the incorporation of modified PVC was studied by AFM and SEM techniques. The effect on hydrophilicity and performance of blends owing to incorporation of modified PVC was evaluated by water uptake, contact angle and flux studies. The density of functional groups in blends was analyzed by its ion-exchange capacity. Batch wise filtration of metal ions was carried out and the effect of pressure, feed pH and interference of ions was thoroughly investigated. Essentially, 100% rejection was obtained for all the metal ions in acidic pH with a productivity of 2.56 l/m{sup 2} h. The results were correlated with the results of commercially available NF 270 membrane under the same operating conditions.

Novel modified poly vinyl chloride blend membranes for removal of heavy metals from mixed ion feed sample

International Nuclear Information System (INIS)

Nayak, Vignesh; Jyothi, M.S.; Balakrishna, R. Geetha; Padaki, Mahesh; Deon, Sebastien

2017-01-01

Highlights: • Work reports the novel modification of poly vinyl chloride (PVC) using newly developed method. • Blend membranes were prepared using modified PVC and polysulfone in different compositions. • The prepared blend membranes were used for separation of different heavy metal ions. • The blend membranes showed improved rejection of heavy metal ions in comparison to Commercial NF 270 membrane. - Abstract: Herein, an attempt has been made to prepare a novel membrane with good efficiency for removal of heavy metal ions namely lead (Pb), cadmium (Cd) and chromium (Cr). 4-amino benzoic acid (ABA) was covalently grafted onto the poly vinyl chloride (PVC) backbone by C−N bond to enhance the hydrophilicity. 1 H NMR and ATR-IR spectroscopy analysis confirmed the chemical modification of PVC. Further the modified polymer was blended in different compositions with polysulfone (PSf) for optimization. Morphological changes that occurred in blend membranes, due to the incorporation of modified PVC was studied by AFM and SEM techniques. The effect on hydrophilicity and performance of blends owing to incorporation of modified PVC was evaluated by water uptake, contact angle and flux studies. The density of functional groups in blends was analyzed by its ion-exchange capacity. Batch wise filtration of metal ions was carried out and the effect of pressure, feed pH and interference of ions was thoroughly investigated. Essentially, 100% rejection was obtained for all the metal ions in acidic pH with a productivity of 2.56 l/m 2 h. The results were correlated with the results of commercially available NF 270 membrane under the same operating conditions.

Effects of Additives on the Morphology and Performance of PPTA/PVDF in Situ Blend UF Membrane

Directory of Open Access Journals (Sweden)

Hong-Bin Li

2014-06-01

Full Text Available Poly(p-phenylene terephtalamide (PPTA, a high-performance polymer with high modulus and good hydrophilicity, is often used as a reinforced material. However, due to its high crystallity, micro-phase separation often occurs in the blends. In this paper, PPTA/poly(vinylidene fluoride (PVDF compatible blend solution was synthesized by in situ polycondensation. Blend ultra-filtration membrane was prepared through the immersion phase inversion process. In order to obtain desired pore structure, the effects of different additives including hydrophilic polymer (polyethylene glycol (PEG, inorganic salt (lithium chloride (LiCl and the surfactant (Tween-80 on the morphology and performance of PPTA/PVDF blend membranes were studied. The membrane formation process was investigated through ternary phase diagram (thermodynamics and viscosities (kinetics analysis. It was found that, with the increasing of LiCl content, a porous membrane structure with long finger-like pores was formed due to the accelerated demixing process which resulted in the increase of porosity and pore diameter as well as the enhancement of water flux and the decline of PEG rejection. When Tween content increased to over 3 wt%, dynamic viscosity became the main factor resulting in a decreased phase separation rate. The transfer of PEG and LiCl molecules onto membrane surface increased the surface hydrophilicity. The effect of Tween content on membrane hydrophilicity was also correlated with the compatibility of blend components.

Morphology and performance of polyvinylidene fluoride/perfluoro sulphonic acid hollow fiber ultrafiltration blend membranes

International Nuclear Information System (INIS)

Yuan, Guo-Lin; Xu, Zhen-Liang; Wei, Yong-Ming; Yu, Li-Yun

2009-01-01

Polyvinylidene fluoride-perfluoro sulphonic acid hollow fibre ultrafiltration blend membranes were prepared by wet-spinning method. Polyvinylpyrrolidone and ethanol aqueous solutions were employed as additive and coagulants, respectively. The effect of Polyvinylpyrrolidone concentration in the dopes and ethanol concentration in the coagulants on morphology and performance of Polyvinylidene fluoride -perfluoro sulphonic acid hollow fibre ultrafiltration blend membranes were investigated. Blend membranes were characterized in terms of precipitation kinetics, morphology, thermal property and separation performance. The results showed that the increments of Polyvinylpyrrolidone concentration in the dopes and ethanol concentration in coagulants both resulted in higher pure water permeation flux and worse rejection (R) of bovine serum albumin (with the increment of Polyvinylpyrrolidone concentration from 0 to 5 wt% in the dopes, pure water permeation increased from 41.7 L.m -2 .h -1 to 134 L.m -2 .h -1 and R decreased from 99.8% to 84.4% as well as with the increase in ethanol concentration in coagulants from 0 to 40 wt%, pure water permeation increased from 33.5 L.m -2 .h- 1 to 123 L.m -2 .h -1 and R decreased from 97.7% to 88.7%). However, the proportion of sponge-like structure in the cross-section of membranes decreased with the increasing Polyvinylpyrrolidone concentration in the dopes and the proportion increased with the increased ethanol concentration in the coagulations. In addition, the location of the sponge-like structure in the cross-section of membranes was significantly influenced by ethanol concentrations in the coagulants and differential scanning calorimeter results revealed that the crystallinity (X c ) of the blend membrane was in accordance with the proportion of sponge-like structure. These behaviours were attributed to the different roles of Polyvinylpyrrolidone in the dopes and ethanol in the coagulants, respectively. Polyvinylidene fluoride

Polymeric blend nanocomposite membranes for ethanol dehydration-effect of morphology and membrane-solvent interactions

Science.gov (United States)

Nanocomposite membranes (NCMs) of sodium alginate/poly(vinyl pyrrolidone) blend polymers incorporated with varying concentrations of phosphotungstic acid (H3PW12O40) (PWA) nanoparticles have been prepared and used in ethanol dehydration by the pervaporation (PV) technique. Effe...

Preparation, Characterization and Permeation Behavior of Poly(methyl acrylate-Poly(dimethyl siloxane-Poly(methyl acrylate Block Copolymer/Poly(vinyl acetate Blend Membranes

Directory of Open Access Journals (Sweden)

Mohammad Ali Semsarzadeh

2015-03-01

Full Text Available Structure of polymeric materials is of the most important factors in determination of the characteristics and properties of the membranes. Various research and developments on polymeric membranes confirm the direct correlation between structure-properties of polymeric membranes. In this research, the structural outcome of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate/poly(vinyl acetate blend membranes and its relationship with gas permeation behavior of the blends were investigated. The flexible block copolymer of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate (PMA-PDMS-PMA was synthesized via atom transfer radical polymerization. Morphology and chemical structure of the synthesized block copolymer was investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, X-ray diffraction analysis, differential scanning calorimetry and scanning electron microscopy. Blend membranes of PMA-PDMS-PMA and poly(vinyl acetate (PVAc were prepared by solution casting method in different compositions. By adding poly(vinyl acetate to PMA-PDMS-PMA block copolymer, the selectivity of the membranes for carbon dioxide/methane pair gases were increased by 55%. Fractional free volume (an indication of chain packing efficiency in blend membranes and dielectric constant (an indication of the molar volume and molar polarization of the blend membranes were obtained as the factors reflected the microstructural effect of PMA-PDMS-PMA and PVAc blend membranes. The efforts were directed toward expressing more precise structure-properties relationship of PMA-PDMS-PMA/PVAc blend membranes. The experimental permeability values of the blend membranes reported in this research were compared with the modified logarithmic model. The modified logarithmic model was evaluated for other blend membranes.

Properties investigation of sulfonated poly(ether ether ketone)/polyacrylonitrile acid-base blend membrane for vanadium redox flow battery application.

Science.gov (United States)

Li, Zhaohua; Dai, Wenjing; Yu, Lihong; Liu, Le; Xi, Jingyu; Qiu, Xinping; Chen, Liquan

2014-11-12

Acid-base blend membrane prepared from sulfonated poly(ether ether ketone) (SPEEK) and polyacrylonitrile (PAN) was detailedly evaluated for vanadium redox flow battery (VRFB) application. SPEEK/PAN blend membrane exhibited dense and homogeneous cross-section morphology as scanning electron microscopy and energy-dispersive X-ray spectroscopy images show. The acid-base interaction of ionic cross-linking and hydrogen bonding between SPEEK and PAN could effectively reduce water uptake, swelling ratio, and vanadium ion permeability, and improve the performance and stability of blend membrane. Because of the good balance of proton conductivity and vanadium ion permeability, blend membrane with 20 wt % PAN (S/PAN-20%) showed higher Coulombic efficiency (96.2% vs 91.1%) and energy efficiency (83.5% vs 78.4%) than Nafion 117 membrane at current density of 80 mA cm(-2) when they were used in VRFB single cell. Besides, S/PAN-20% membrane kept a stable performance during 150 cycles at current density of 80 mA cm(-2) in the cycle life test. Hence the SPEEK/PAN acid-base blend membrane could be used as promising candidate for VRFB application.

Combined impact of branching and unsaturation on the autoignition of binary blends in a motored engine

KAUST Repository

Kang, Dongil

2014-11-20

The impact of a branched and unsaturated compound (diisobutylene) mixed with simple hydrocarbons such as n-heptane and isooctane in binary blends on the autoignition behavior were investigated in a modified cooperative fuel research (CFR) engine at an equivlanece ratio of 0.5 and intake temperature of 120 °C. From this test condition, a homogeneous charge of fuel and intake air can be achieved. The test fuels were prepared by addition of 5-20 vol % diisobutylene into n-heptane and isooctane. The engine compression ratio (CR) was gradually increased from the lowest point to the point where significant high temperature heat release (HTHR) was observed, and this point is also referred to as the critical compression ratio (CCR). Heat release analysis showed that each n-heptane blend had a noticeable low temperature heat release (LTHR), which was not observed in the isooctane blends. The gradual addition of diisobutylene into each primary reference fuel contributed to retarded high temperature heat release in these binary blends, increasing the in-cylinder temperature and decreasing formation of CO. The 15 and 20 vol % blends of diisobutylene in isooctane were not able to reach high temperature heat release in the CFR engine system under these test conditions. The fundamental ignition behavior such as CCR and calculated % LTHR show the impact of the presence of the C-C double bond on ignition reactivity. Species concentration profiles obtained in condensed products from the engine exhaust were measured via gas chromatrography-mass spectrometry and -flame ionization detector. The major intermediate species for each blend were captured at a compression ratio selected just before the high temperature heat release was observed. Most intermediate species were derived from n-heptane and isooctane, while diisobutylene rarely participated in forming any major species, with the exception of the formation of 4,4-dimethyl-2-pentanone. Addition of diisobutylene exhibited opposite

Combined impact of branching and unsaturation on the autoignition of binary blends in a motored engine

KAUST Repository

Kang, Dongil; Kirby, Stephen R.; Agudelo, John Ramiro; Lapuerta, Magí n; Al-Qurashi, Khalid; Boehman, André Louis

2014-01-01

The impact of a branched and unsaturated compound (diisobutylene) mixed with simple hydrocarbons such as n-heptane and isooctane in binary blends on the autoignition behavior were investigated in a modified cooperative fuel research (CFR) engine at an equivlanece ratio of 0.5 and intake temperature of 120 °C. From this test condition, a homogeneous charge of fuel and intake air can be achieved. The test fuels were prepared by addition of 5-20 vol % diisobutylene into n-heptane and isooctane. The engine compression ratio (CR) was gradually increased from the lowest point to the point where significant high temperature heat release (HTHR) was observed, and this point is also referred to as the critical compression ratio (CCR). Heat release analysis showed that each n-heptane blend had a noticeable low temperature heat release (LTHR), which was not observed in the isooctane blends. The gradual addition of diisobutylene into each primary reference fuel contributed to retarded high temperature heat release in these binary blends, increasing the in-cylinder temperature and decreasing formation of CO. The 15 and 20 vol % blends of diisobutylene in isooctane were not able to reach high temperature heat release in the CFR engine system under these test conditions. The fundamental ignition behavior such as CCR and calculated % LTHR show the impact of the presence of the C-C double bond on ignition reactivity. Species concentration profiles obtained in condensed products from the engine exhaust were measured via gas chromatrography-mass spectrometry and -flame ionization detector. The major intermediate species for each blend were captured at a compression ratio selected just before the high temperature heat release was observed. Most intermediate species were derived from n-heptane and isooctane, while diisobutylene rarely participated in forming any major species, with the exception of the formation of 4,4-dimethyl-2-pentanone. Addition of diisobutylene exhibited opposite

Deproteinised natural rubber latex grafted poly(dimethylaminoethyl methacrylate) - poly(vinyl alcohol) blend membranes: Synthesis, properties and application.

Science.gov (United States)

Jayadevan, Janisha; Alex, Rosamma; Gopalakrishnapanicker, Unnikrishnan

2018-02-01

Natural rubber latex was initially deproteinised (DNRL) and then subjected to physicochemical modifications to make high functional membranes for drug delivery applications. Initially, DNRL was prepared by incubating with urea, sodiumdodecylsulphate and acetone followed by centrifugation. The deproteinisation was confirmed by CHN analysis. The DNRL was then chemically modified by grafting (dimethylaminoethyl methacrylate) onto NR particles by using a redox initiator system viz; cumene hydroperoxide/tetraethylenepentamine, followed by dialysis for purification. The grafting was confirmed by dynamic light scattering, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The grafted system was blended with a hydrophilic adhesive polymer PVA and casted into membranes. The membranes after blending showed enhanced mechanical properties with a threshold concentration of PVA. The moisture uptake, swelling and water contact angle experiments indicated an increased hydrophilicity with an increased PVA content in the blend membranes. The grafted DNRL possessed significant antibacterial property which has been found to be retained in the blended form. A notable decrease in cytotoxicity was observed for the modified DNRL membranes than the bare DNRL membranes. The in-vitro drug release studies using rhodamine B as a model drug, confirmed the utility of the prepared membranes to function as a drug delivery matrix. Copyright © 2017 Elsevier B.V. All rights reserved.

Poly(vinyl-alcohol)/poly(ethylene-glycol)/poly(ethylene-imine) blend membranes - structure and CO2 facilitated transport

International Nuclear Information System (INIS)

Ben Hamouda, S.; Quang, Trong Nguyen; Langevin, D.; Sadok, Roudeslic

2010-01-01

Poly(vinyl-alcohol) (PVA)/poly(ethylene-imine) (PEI)/poly(ethylene-glycol) (PEG) blend membranes were prepared by solution casting followed by solvent evaporation. The effects of the blend polymer composition on the membrane structure and CO 2 /N 2 permeation characteristics were investigated. IR spectroscopy evidenced strong hydrogen bonding interactions between amorphous PVA and PEI, and weaker interactions between PVA and PEG. DSC studies showed that PVA crystallization was partially inhibited by the interactions between amorphous PVA and PEI blend, in which PEG separated into nodules. The CO 2 permeability decreased with an increase in CO 2 partial pressure in feed gas, while the N 2 permeability remained constant. This result indicated that only CO 2 was transported by the facilitated transport mechanism. The CO 2 and N 2 permeabilities increased monotonically with the PEI content in the blend membranes, whereas the ideal selectivity of CO 2 to N 2 transport showed a maximum. When CO 2 is humidified, its permeability through the blend membranes is much higher than that of dry CO 2 , but the change in permeability due to the presence of humidity is reversible. (authors)

Complex Macrophase-Separated Nanostructure Induced by Microphase Separation in Binary Blends of Lamellar Diblock Copolymer Thin Films

DEFF Research Database (Denmark)

Zhang, Jianqi; Posselt, Dorthe; Smilgies, Detlef-M.

2014-01-01

The nanostructures of thin films spin-coated from binary blends of compositionally symmetric polystyrene-b-polybutadiene (PS-b-PB) diblock copolymer having different molar masses are investigated by means of atomic force microscopy (AFM) and grazing-incidence small-angle X-ray scattering (GISAXS)...

Morphology development in immiscible polymer blends

NARCIS (Netherlands)

Cardinaels, R.M.; Moldenaers, P.; Guo, Qipeng

This chapter discusses the morphology development of immiscible binary polymer blends. It first describes morphology development in droplet-matrix structures, the dynamics of fibrillar structures and cocontinuous structures. The chapter then considers binary immiscible polymer blends, such systems

Binary blend Nanoparticles with defined morphology

International Nuclear Information System (INIS)

Ghazy, O.A.H.

2008-01-01

The word blend in linguistics means a word formed from two parts of two words. In polymer science polymer blends means polymer mixtures, a class of materials analogues to the metal alloys. Blending of polymers is a simple and economic way to create new materials meeting specific desired properties. The other alternative is to synthesize such materials eventually facing the organic chemistry design difficulties. The low entropy of mixing polymers makes the process thermodynamically unfavorable, unless there are some specific interactions between the mixed polymers. As a result, in thermal equilibrium typically a phase separation between the blend components takes place. The main challenge facing the blending of polymers is the control of the length scale of the phase separation. One of the most important applications, where the control of the phase separation is crucial for the performance is the organic solar cells. In organic solar cells a blend of an electron donating polymer and electron accepting one is formed. The dimensions of the phase separation between the two polymers should be in the range of the exciton diffusion length [1-3] (in semiconductors, exciton diffusion length is the average distance traveled by the electron-hole pair before recombination). Only under this condition the charge transfer at the interface between the two polymer layers can take place and the solar cell performs efficiently. The thin polymer blend layers for such applications are commonly deposited by spin coating from solution containing both polymers. The morphology of the thin layer prepared in this way is highly influenced by the preparation conditions such as the surface properties of the substrate, the solvent from which the blend was deposited, the temperature, and the annealing temperature [4-9]. Therefore controlling the length scale of phase separation in layers casted or spin coated from solutions is difficult and is a matter of trials and errors. Recently a novel

Transport Properties, Mechanical Behavior, Thermal and Chemical Resistance of Asymmetric Flat Sheet Membrane Prepared from PSf/PVDF Blended Membrane on Gauze Supporting Layer

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Nita Kusumawati

2018-05-01

Full Text Available Asymmetric polysulfone (PSf membrane is prepared using phase inversion method and blending with polyvinylidene fluoride (PVDF on the gauze solid support. Casting solution composition optimization has been done to get PSf/PVDF membrane with best characteristics and permeability. The result shows that blending on PSf with PVDF polymer using phase inversion method has been very helpful in creating an asymmetric porous membrane. Increased level of PVDF in casting solution has increased the formation of asymmetry structure and corresponding flux membrane. The result from thermal test using Differential Scanning Calorimetry (DSC-Thermal Gravimetric Analysis (TGA shows the resistance of the membrane to temperature 460 °C. Membrane resistance against acid looks from undetectable changes on infrared spectra after immersion process in H2SO4 6–98 v/v%. While membrane color changes from white to brownish and black is detected after the immersion process in sodium hydroxide (NaOH 0.15–80 w/v%.

Viability and Biomechanics of Diced Cartilage Blended With Platelet-Rich Plasma and Wrapped With Poly (Lactic-Co-Glycolic) Acid Membrane.

Science.gov (United States)

Liao, Jun-Lin; Chen, Jia; He, Bin; Chen, Yong; Xu, Jia-Qun; Xie, Hong-Ju; Hu, Feng; Wang, Ai-Jun; Luo, ChengQun; Li, Qing-Feng; Zhou, Jian-Da

2017-09-01

The objective of this study was to investigate the viability and biomechanics of diced cartilage blended with platelet-rich plasma (PRP) and wrapped with poly (lactic-co-glycolic) acid (PLGA) membrane in a rabbit model. A total of 10 New Zealand rabbits were used for the study. Cartilage grafts were harvested from 1 side ear. The grafts were divided into 3 groups for comparison: bare diced cartilage, diced cartilage wrapped with PLGA membrane, and diced cartilage blended with PRP and wrapped with PLGA membrane. Platelet-rich plasma was prepared using 8 mL of auricular blood. Three subcutaneous pockets were made in the backs of the rabbits, and the grafts were placed in these pockets. The subcutaneous implant tests were conducted for safety assessment of the PLGA membrane in vivo. All of the rabbits were sacrificed at the end of 3 months, and the specimens were collected. The sections were stained with hematoxylin and eosin, toluidin blue, and collagen II immunohistochemical. Simultaneously, biomechanical properties of grafts were assessed. This sample of PLGA membrane was conformed to the current standard of biological evaluation of medical devices. Moderate resorption was seen at the end of 3 months in the gross assessment in diced cartilage wrapped with PLGA membrane, while diced cartilage blended with PRP had no apparent resorption macroscopically and favorable viability in vivo after 3 months, and the histological parameters supported this. Stress-strain curves for the compression test indicated that the modulus of elasticity of bare diced cartilage was 7.65 ± 0.59 MPa; diced cartilage wrapped with PLGA membrane was 5.98 ± 0.45 MPa; and diced cartilage blended with PRP and wrapped with PLGA membrane was 7.48 ± 0.55 MPa, respectively. Diced cartilage wrapped with PLGA membrane had moderate resorption macroscopically after 3 months. However, blending with PRP has beneficial effects in improving the viability of diced cartilages. Additionally, the

Study of flame combustion of off-design binary coal blends in steam boilers

Science.gov (United States)

Kapustyanskii, A. A.

2017-07-01

Changes in the structure of the fuel consumption by the thermal power stations of Ukraine caused by failure in supplying anthracite from the Donets Basin are analyzed and the major tasks of maintaining the functioning of the coal industry are formulated. The possibility of using, in the near future, the flame combustion of off-design solid fuels in the power boilers of the thermal power plants and combined heat and power plants is studied. The article presents results of expert tests of the TPP-210A and TP-15 boilers under flame combustion of mixtures of anthracites, lean coal, and the coal from the RSA in various combinations. When combusting, such mixtures have higher values of the combustibles yield and the ash fusibility temperature. The existence of the synergetic effect in the flame combustion of binary coal blends with different degrees of metamorphism is discussed. A number of top-priority measures have been worked out that allow for switching over the boilers designed to be fired with anthracite to using blends of coals of different ranks. Zoned thermal analysis of the TP-15 boiler furnace was performed for numerical investigation of the temperature distribution between the furnace chamber zones and exploration of the possibility of the liquid slag disposal and the temperature conditions for realization of this process. A positive result was achieved by combusting anthracite culm (AC), the coal from the RSA, and their mixtures with lean coal within the entire range of the working loads of the boilers in question. The problems of normalization of the liquid slag flow were also successfully solved without closing the slag notch. The results obtained by balance experiments suggest that the characteristics of the flame combustion of a binary blend, i.e., the temperature conditions in the furnace, the support flame values, and the degree of the fuel burnout, are similar to the characteristics of the flame of the coal with a higher reactive capacity, which

Preparation of Citric Acid Crosslinked Chitosan/Poly(Vinyl Alcohol Blend Membranes for Creatinine Transport

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Retno Ariadi Lusiana

2016-08-01

Full Text Available Preparation of membrane using crosslinking reaction between chitosan and citric acid showed that functional group modification increased the number of active carrier groups which lead to better transport capacity of the membrane. In addition, the substitution of the carboxyl group increased creatinine permeation of chitosan membrane. The transport capacity of citric acid crosslinked chitosan membrane for creatinine was found to be 6.3 mg/L. The presence of cyanocobalamin slightly hindered the transport of creatinine although compounds did not able to pass through citric acid crosslinked chitosan/poly(vinyl alcohol blend membrane, as compounds no found in the acceptor phase.

Preparation and characterization of poly (methyl methacrylate) and sulfonated poly (ether ether ketone) blend ultrafiltration membranes for protein separation applications

International Nuclear Information System (INIS)

Arthanareeswaran, G.; Thanikaivelan, P.; Raajenthiren, M.

2009-01-01

Poly (methyl methacrylate) (PMMA) and poly (methyl methacrylate)/sulfonated poly (ether ether ketone) (SPEEK) blend membranes were prepared by phase inversion technique in various composition using N,N'-dimethylformamide as solvent. The prepared membranes were characterized in terms of pure water flux, water content, porosity and thermal stability. The addition of SPEEK to the casting solution resulted in membranes with high pure water flux, water content, porosity and slightly low thermal stability. The cross sectional views of the blend membranes under electron microscope confirm the porosity and water flux results. The effect of the addition of SPEEK into the PMMA matrix on the extent of bovine serum albumin (BSA) separation was studied. It was found that the permeate flux increased significantly while the rejection of BSA from aqueous solution reduced moderately during ultrafiltration (UF) process. The effect was attributed to the increase in porosity and charge of the membrane due to the addition of SPEEK into the PMMA blend solution

Enhanced proton conductivity by the influence of modified montmorillonite on poly (vinyl alcohol) based blend composite membranes

Energy Technology Data Exchange (ETDEWEB)

Palani, P. Bahavan, E-mail: bahavanpalani@gmail.com; Abidin, K. Sainul [Department of Physics, University College of Engineering, Anna University, Dindigul-624622 (India); Kannan, R., E-mail: rksrsrk@gmail.com [Department of Physics, University College of Engineering, Anna University, Dindigul-624622 (India); Department of Material Sciences & Engineering, Cornell University, Ithaca, NewYork-14853 (United States); Rajashabala, S. [School of Physics, Madurai Kamaraj University, Madurai-625021 (India); Sivakumar, M. [School of Physics, Alagappa University, Karaikudi-630004 (India)

2016-05-23

The highest proton conductivity value of 0.0802 Scm{sup −1} is obtained at 6 wt% of protonated MMT added to the PVA/PEG blends. The polymer blend composite membranes are prepared with varied concentration of Poly vinyl alcohol (PVA), Poly ethylene glycol (PEG) and Montmorillonite (MMT) by solution casting method. The Na{sup +} MMT was modified (protonated) to H{sup +} MMT with ion exchange process. The prepared membranes were characterized by using TGA, FTIR, XRD, Ion Exchange Capacity, Water/Methanol uptake, swelling ratio and proton conductivity. The significant improvements in the hydrolytic stability were observed. In addition, thermal stability of the composite membranes were improved and controlled by the addition of MMT. All the prepared membranes are shown appreciable values of proton conductivity at room temperature with 100% relative humidity.

Investigation on Nano composite Membrane of Multi walled Carbon Nano tube Reinforced Polycarbonate Blend for Gas Separation

International Nuclear Information System (INIS)

Kausar, A.

2016-01-01

Carbon nano tube has been explored as a nano filler in high performance polymeric membrane for gas separation. In this regard, nano composite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multi walled carbon nano tube (MWCNT) was fabricated via phase inversion technique. Poly (ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nano filler. Scanning and transmission electron micrographs have shown fine nano tube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young s modulus of PC/PVFHFP/PEG/MWCNT-A 1-5 were found to be in the range of 63.6-72.5 MPa and 110.6-122.1 MPa, respectively. The nano composite revealed 51% increase in Young s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the perm selectivity αCO 2 /N 2 (31.2-39.9) of nano composite membrane relative to the blend membrane (21.6). The permeability ρCO 2 of blend was 125.6 barrer; however, the functional series had enhancedρCO 2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1-5; however, filler content did not significantly influence the CO 2 and N 2 solubility.

Preparation of hydrophilic PVDF/PPTA blend membranes by in situ polycondensation and its application in the treatment of landfill leachate

International Nuclear Information System (INIS)

Li, Hongbin; Shi, Wenying; Zhang, Yufeng; Zhou, Rong; Zhang, Haixia

2015-01-01

Graphical abstract: - Highlights: • High modulus PPTA molecules were introduced into PVDF membrane matrix through in situ polycondensation. • Membrane surface hydrophilicity and mechanical strength were improved. • An enhanced antifouling property was obtained when blend membrane was applied in the MBR in the treatment of landfill leachate. • Blend membrane also showed a relatively high removal rate of chemical oxygen demand (COD) and chrom. - Abstract: High modulus poly(p-phenylene terephtalamide) (PPTA) reinforced composites are of great scientific interests. But the thermodynamic difference makes the polymer pairs incompatible and endows the composites with inferior physical-chemical properties. In this study, hydrophilic poly(vinylidene fluoride) (PVDF)/poly(p-phenylene terephtalamide) (PPTA) blend membrane with improved hydrophilicity and mechanical strength was prepared through in situ polycondensation of p-phenylene diamine (PPD) and terephthaloyl chloride (TPC) in PVDF solution and subsequent immersion precipitation phase inversion process. The effects of PPTA concentration in polymer dopes on membrane formation process, structure, morphology and performance were systematically investigated. The results showed that thermodynamically, PPTA acted as a demixing enhancer which accelerated the phase inversion process. Dynamically, liquid-liquid phase separation was still in control of membrane formation process especially in the later period, whereas the addition of PPTA mainly promoted the early emergence of the liquid-liquid demixing. The surface hydrophilicity, ant-fouling properties and mechanical strength were significantly improved when PPTA content was 17 wt%. When PPTA content increased to 26 wt%, membrane bursting pressure increased to nearly 0.6 MPa which was 1.5 times higher than that of PVDF membrane. The resultant PVDF/PPTA blend membrane exhibited an improved antifouling property than that of PVDF membrane when applied in the MBR in the

Preparation of hydrophilic PVDF/PPTA blend membranes by in situ polycondensation and its application in the treatment of landfill leachate

Energy Technology Data Exchange (ETDEWEB)

Li, Hongbin, E-mail: qinyu1105@126.com [School of Textiles Engineering, Henan Institute of Engineering, Zhengzhou, 450007 (China); Shi, Wenying [School of Textiles Engineering, Henan Institute of Engineering, Zhengzhou, 450007 (China); Zhang, Yufeng [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Zhou, Rong; Zhang, Haixia [School of Textiles Engineering, Henan Institute of Engineering, Zhengzhou, 450007 (China)

2015-08-15

Graphical abstract: - Highlights: • High modulus PPTA molecules were introduced into PVDF membrane matrix through in situ polycondensation. • Membrane surface hydrophilicity and mechanical strength were improved. • An enhanced antifouling property was obtained when blend membrane was applied in the MBR in the treatment of landfill leachate. • Blend membrane also showed a relatively high removal rate of chemical oxygen demand (COD) and chrom. - Abstract: High modulus poly(p-phenylene terephtalamide) (PPTA) reinforced composites are of great scientific interests. But the thermodynamic difference makes the polymer pairs incompatible and endows the composites with inferior physical-chemical properties. In this study, hydrophilic poly(vinylidene fluoride) (PVDF)/poly(p-phenylene terephtalamide) (PPTA) blend membrane with improved hydrophilicity and mechanical strength was prepared through in situ polycondensation of p-phenylene diamine (PPD) and terephthaloyl chloride (TPC) in PVDF solution and subsequent immersion precipitation phase inversion process. The effects of PPTA concentration in polymer dopes on membrane formation process, structure, morphology and performance were systematically investigated. The results showed that thermodynamically, PPTA acted as a demixing enhancer which accelerated the phase inversion process. Dynamically, liquid-liquid phase separation was still in control of membrane formation process especially in the later period, whereas the addition of PPTA mainly promoted the early emergence of the liquid-liquid demixing. The surface hydrophilicity, ant-fouling properties and mechanical strength were significantly improved when PPTA content was 17 wt%. When PPTA content increased to 26 wt%, membrane bursting pressure increased to nearly 0.6 MPa which was 1.5 times higher than that of PVDF membrane. The resultant PVDF/PPTA blend membrane exhibited an improved antifouling property than that of PVDF membrane when applied in the MBR in the

Blend membrane of succinic acid-crosslinked chitosan grafted with heparin/PVA-PEG (polyvinyl alcohol-polyethylene glycol) and its characterization

Science.gov (United States)

Sangkota, V. D. A.; Lusiana, R. A.; Astuti, Y.

2018-04-01

Crosslinking and grafting reactions are required to modify the functional groups on chitosan to increase the number of its active groups. In this study, crosslinking reaction of succinic acid and grafting reaction of heparin on chitosan were conducted to produce a membrane as a candidate of a hemodialysis membrane. The mole ratio between chitosan and succinate acids was varied to obtain the best composition of modified materials. By blending all the material composition with PVA-PEG, the blend was transformed into a membrane. The resulted membrane was then characterized by various test methods such as tests of thickness, weight, water uptake, pH resistance, tensile strength and membrane hydrophilicity. The results showed that the best composition of the membrane reached in the addition of 0.011 gram of succinic acid proved by its highest mechanical strength compared to the other membranes.

Effect of solvent evaporation and coagulation on morphology development of asymmetric membranes

Science.gov (United States)

Chandrasekaran, Neelakandan; Kyu, Thein

2008-03-01

Miscibility behavior of blends of amorphous polyamide (PA) and polyvinylpyrrolidone (PVP) was studied in relation to membrane formation. Dimethylsulfoxide (DMSO) and water were used as solvent and non-solvent, respectively. Differential scanning calorimetry and cloud point measurements revealed that the binary PA/PVP blends as well as the ternary PA/PVP/DMSO system were completely miscible at all compositions. However, the addition of non-solvent (water) to this ternary system has led to phase separation. Visual turbidity study was used to establish a ternary liquid-liquid phase diagram of the PA-PVP/DMSO/water system. Scanning Electron Microscopy (SEM) showed the development of finger-like and sponge-like cross sectional morphologies during coagulation. Effects of polymer concentration, PA/PVP blend ratio, solvent/non-solvent quality, and evaporation time on the resulting membrane morphology will be discussed.

Novel process integration for biodiesel blend in membrane reactive divided wall (MRDW column

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Sakhre Vandana

2016-03-01

Full Text Available The paper proposes a novel process integration for biodiesel blend in the Membrane assisted Reactive Divided Wall Distillation (MRDW column. Biodiesel is a green fuel and grade of biodiesel blend is B20 (% which consist of 20% biodiesel and rest 80% commercial diesel. Instead of commercial diesel, Tertiary Amyl Ethyl Ether (TAEE was used as an environment friendly fuel for blending biodiesel. Biodiesel and TAEE were synthesized in a pilot scale reactive distillation column. Dual reactive distillation and MRDW were simulated using aspen plus. B20 (% limit calculation was performed using feed flow rates of both TAEE and biodiesel. MRDW was compared with dual reactive distillation column and it was observed that MRDW is comparatively cost effective and suitable in terms of improved heat integration and flow pattern.

Proton exchange membranes from sulfonated polyetheretherketone and sulfonated polyethersulfone-cardo blends: Conductivity, water sorption and permeation properties

International Nuclear Information System (INIS)

Li, Yongli; Nguyen, Quang Trong; Schaetzel, Pierre; Lixon-Buquet, Camille; Colasse, Laurent; Ratieuville, Vincent

2013-01-01

Five blend membranes were prepared by solvent evaporation from solutions of the synthesized sulfonated polyetheretherketone (SPEEK) and sulfonated polyethersulfone-cardo (SPESc). Their ion exchange capacity and degree of sulfonation determined by acid–base titration and by thermogravimetric analysis were consistent. The blends glass transition behavior obtained by differential scanning calorimetry suggests that the two sulfonated polymers are compatible in the whole composition range. The values of the activation energy for proton transport determined by conductivity measurements on the SPEEK-based blend membranes were in the range of 13–34 kJ mol −1 , which suggest a mixed transport mechanism that involves both proton jumps on ionic sites and water of hydration and diffusion of proton–water complex in hydrophilic domains. The water vapor sorption in the membranes exhibits sigmoid-shape isotherms which were well fitted by the “new dual mode sorption” model, and the fitted parameters values were successfully used to model the change in the water permeation flux with the upstream water activity using the first Fick's diffusion equation. The fast increase in the permeation flux beyond a critical value of activity (0.5) was owing to the exponential concentration-dependent diffusion coefficient. These modelings allowed us to show a strong increase in the limit diffusion coefficient of water and a decrease in the water-diffusion plasticization coefficient with the SPEEK content in the polymer blends

Phase Behavior of Binary Blends of AB+AC Block Copolymers with compatible B and C blocks

Science.gov (United States)

Pryamitsyn, Victor; Ganesan, Venkat

2012-02-01

Recently the experimental studies of phase behavior of binary blends of PS-b-P2VP and PS-b-PHS demonstrated an interesting effect: blends of symmetric PS-b-P2VP and shorter symmetric (PS-b-PHS) formed cylindrical HEX and spherical BCC phases, while each pure component formed lamellas. The miscibility of P2VP and PHS is caused by the hydrogen bonding between P2VP and PHS,which can be described as a negative Flory ?-parameter between P2VP and PHS. We developed a theory of the microphase segregation of AB+AC blends of diblock copolymers based on strong stretching theory. The main result of our theory is that in the copolymer brush-like layer formed by longer B chain and shorter C chains, the attraction between B and shorter C chains causes relative stretching of short C chains and compression of longer B chains. The latter manifests in an excessive bending force towards the grafting surface (BC|AA interface). Such bending force causes a transition from a symmetric lamella phase to a HEX cylinder or BCC spherical phases with the BC phase being a ``matrix'' component. In a blend of asymmetric BCC sphere forming copolymers (where B and C segments are the minor components), such bending force may unfold BCC spherical phase to a HEX cylinder phase, or even highly uneven lamella phases.

Effects of a tetracycline blended polylactic and polyglycolic acid membrane on the healing of one-wall intrabony defects in beagle dogs

International Nuclear Information System (INIS)

Kim, Il-Young; Jung, Ui-Won; Kim, Chang-Sung; Lee, Yong-Keun; Cho, Kyoo-Sung; Chai, Jung-Kiu; Kim, Chong-Kwan; Choi, Seong-Ho

2007-01-01

The purpose of this study was to evaluate the regenerative effects of a tetracycline blended polylactic and polyglycolic acid (TC-PLGA) and non-blended polylactic and polyglycolic acid (PLGA) barrier membrane on one-wall intrabony defects in beagle dogs. It can be concluded that when used for guided tissue regeneration TC-PLGA membranes show a beneficial effect on one-wall intrabony defects in beagle dogs

Binary blend of carbon dioxide and fluoro ethane as working fluid in transcritical heat pump systems

Directory of Open Access Journals (Sweden)

Zhang Xian-Ping

2015-01-01

Full Text Available As an eco-friendly working fluid, carbon dioxide or R744 is expected to substitute for the existing working fluids used in heat pump systems. It is, however, challenged by the much higher heat rejection pressure in transcritical cycle compared with the traditional subcritical cycle using freons. There exists a worldwide tendency to utilize blend refrigerants as alternatives. Therefore, a new binary blend R744/R161 in this research is proposed in order to decrease the heat rejection pressure. Meanwhile, on mixing R744 with R161, the flammability and explosivity of R161 can be suppressed because of the extinguishing effect of R744. A transcritical thermodynamic model is developed, and then the system performances of heat pump using R744/R161 blend are investigated and compared with those of pure R744 system under the same operation conditions. The variations of heat rejection pressure, heating coefficient of performance, unit volumetric heating capacity, discharge temperature of compressor and the mass fraction of R744/R161 are researched. The results show that R744/R161 mixture can reduce the heat rejection pressure of transcritical heat pump system.

Measuring the composition-curvature coupling in binary lipid membranes by computer simulations

International Nuclear Information System (INIS)

Barragán Vidal, I. A.; Müller, M.; Rosetti, C. M.; Pastorino, C.

2014-01-01

The coupling between local composition fluctuations in binary lipid membranes and curvature affects the lateral membrane structure. We propose an efficient method to compute the composition-curvature coupling in molecular simulations and apply it to two coarse-grained membrane models—a minimal, implicit-solvent model and the MARTINI model. Both the weak-curvature behavior that is typical for thermal fluctuations of planar bilayer membranes as well as the strong-curvature regime corresponding to narrow cylindrical membrane tubes are studied by molecular dynamics simulation. The simulation results are analyzed by using a phenomenological model of the thermodynamics of curved, mixed bilayer membranes that accounts for the change of the monolayer area upon bending. Additionally the role of thermodynamic characteristics such as the incompatibility between the two lipid species and asymmetry of composition are investigated

Measuring the composition-curvature coupling in binary lipid membranes by computer simulations

Energy Technology Data Exchange (ETDEWEB)

Barragán Vidal, I. A., E-mail: vidal@theorie.physik.uni-goettingen.de; Müller, M., E-mail: mmueller@theorie.physik.uni-goettingen.de [Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Rosetti, C. M., E-mail: carla@dqb.fcq.unc.edu.ar [Centro de Investigaciones en Química Biológica de Córdoba, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba (Argentina); Pastorino, C., E-mail: pastor@cnea.gov.ar [Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA/CONICET, Av. Gral. Paz 1499, 1650 Pcia. de Buenos Aires (Argentina)

2014-11-21

The coupling between local composition fluctuations in binary lipid membranes and curvature affects the lateral membrane structure. We propose an efficient method to compute the composition-curvature coupling in molecular simulations and apply it to two coarse-grained membrane models—a minimal, implicit-solvent model and the MARTINI model. Both the weak-curvature behavior that is typical for thermal fluctuations of planar bilayer membranes as well as the strong-curvature regime corresponding to narrow cylindrical membrane tubes are studied by molecular dynamics simulation. The simulation results are analyzed by using a phenomenological model of the thermodynamics of curved, mixed bilayer membranes that accounts for the change of the monolayer area upon bending. Additionally the role of thermodynamic characteristics such as the incompatibility between the two lipid species and asymmetry of composition are investigated.

Novel polyvinylidene fluoride nanofiltration membrane blended with functionalized halloysite nanotubes for dye and heavy metal ions removal

International Nuclear Information System (INIS)

Zeng, Guangyong; He, Yi; Zhan, Yingqing; Zhang, Lei; Pan, Yang; Zhang, Chunli; Yu, Zongxue

2016-01-01

Highlights: • A novel PVDF nanofiltration membrane was prepared by incorporation of A-HNTs. • HNTs dispersed well in membrane matrix after APTES modification. • The membrane exhibited excellent hydrophilicity and antifouling properties. • A high dye and heavy metal ions removal was realized by membrane separation. - Abstract: Membrane separation is an effective method for the removal of hazardous materials from wastewater. Halloysite nanotubes (HNTs) were functionalized with 3-aminopropyltriethoxysilane (APTES), and novel polyvinylidene fluoride (PVDF) nanofiltration membranes were prepared by blending with various concentrations of APTES grafted HNTs (A-HNTs). The morphology structure of the membranes were characterized by scanning electron microscope (SEM) and atomic force microscopy (AFM). The contact angle (CA), pure water flux (PWF) and antifouling capacity of membranes were investigated in detail. In addition, the separation performance of membranes were reflected by the removal of dye and heavy metal ions in simulated wastewater. The results revealed that the hydrophilicity of A-HNTs blended PVDF membrane (A-HNTs@PVDF) was enhanced significantly. Owing to the electrostatic interaction between membrane surface and dye molecules, the dye rejection ratio of 3% A-HNTs@PVDF membrane reached 94.9%. The heavy metal ions rejection ratio and adsorption capacity of membrane were also improved with the addition of A-HNTs. More importantly, A-HNTs@PVDF membrane exhibited excellent rejection stability and reuse performances after several times fouling and washing tests. It can be expected that the present work will provide insight into a new method for membrane modification in the field of wastewater treatment.

Novel polyvinylidene fluoride nanofiltration membrane blended with functionalized halloysite nanotubes for dye and heavy metal ions removal

Energy Technology Data Exchange (ETDEWEB)

Zeng, Guangyong [State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); He, Yi, E-mail: heyi@swpu.edu.cn [State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Zhan, Yingqing; Zhang, Lei; Pan, Yang; Zhang, Chunli; Yu, Zongxue [State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China)

2016-11-05

Highlights: • A novel PVDF nanofiltration membrane was prepared by incorporation of A-HNTs. • HNTs dispersed well in membrane matrix after APTES modification. • The membrane exhibited excellent hydrophilicity and antifouling properties. • A high dye and heavy metal ions removal was realized by membrane separation. - Abstract: Membrane separation is an effective method for the removal of hazardous materials from wastewater. Halloysite nanotubes (HNTs) were functionalized with 3-aminopropyltriethoxysilane (APTES), and novel polyvinylidene fluoride (PVDF) nanofiltration membranes were prepared by blending with various concentrations of APTES grafted HNTs (A-HNTs). The morphology structure of the membranes were characterized by scanning electron microscope (SEM) and atomic force microscopy (AFM). The contact angle (CA), pure water flux (PWF) and antifouling capacity of membranes were investigated in detail. In addition, the separation performance of membranes were reflected by the removal of dye and heavy metal ions in simulated wastewater. The results revealed that the hydrophilicity of A-HNTs blended PVDF membrane (A-HNTs@PVDF) was enhanced significantly. Owing to the electrostatic interaction between membrane surface and dye molecules, the dye rejection ratio of 3% A-HNTs@PVDF membrane reached 94.9%. The heavy metal ions rejection ratio and adsorption capacity of membrane were also improved with the addition of A-HNTs. More importantly, A-HNTs@PVDF membrane exhibited excellent rejection stability and reuse performances after several times fouling and washing tests. It can be expected that the present work will provide insight into a new method for membrane modification in the field of wastewater treatment.

Novel Blend Membranes Based on Acid-Base Interactions for Fuel Cells

Directory of Open Access Journals (Sweden)

Yongzhu Fu

2012-10-01

Full Text Available Fuel cells hold great promise for wide applications in portable, residential, and large-scale power supplies. For low temperature fuel cells, such as the proton exchange membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs, proton-exchange membranes (PEMs are a key component determining the fuel cells performance. PEMs with high proton conductivity under anhydrous conditions can allow PEMFCs to be operated above 100 °C, enabling use of hydrogen fuels with high-CO contents and improving the electrocatalytic activity. PEMs with high proton conductivity and low methanol crossover are critical for lowering catalyst loadings at the cathode and improving the performance and long-term stability of DMFCs. This review provides a summary of a number of novel acid-base blend membranes consisting of an acidic polymer and a basic compound containing N-heterocycle groups, which are promising for PEMFCs and DMFCs.

Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications

Science.gov (United States)

Wang, Shuai; Li, Tong; Chen, Chen; Chen, Sheng; Liu, Baicang; Crittenden, John

2018-03-01

Ultrafiltration (UF) membranes composed of poly(vinylidene fluoride) (PVDF) blended with poly(vinylidene fluoride)-graft-poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) can present high flux and excellent foulant removal efficiencies under suitable preparation conditions. However, these PVDF/PVDF-g-PEGMA blended membranes cannot be applied industrially because of the insufficient mechanical strength (strength-to-break value of 8.4 ± 0.6 MPa). We incorporated two types of non-woven polyethylene terephthalate (PET) fabrics (thin hydrophobic and thick hydrophilic fabrics) as support layers to improve the mechanical properties of the blended membranes. The thin and thick PET fabrics were able to significantly improve the tensile strength to 23.3 ± 3.7 MPa and 30.1 ± 1.4 MPa, respectively. The PET fabrics had a limited impact on the separation-related membrane performance such as hydrophilicity, foulant rejection, whereas the mechanical strength and pure water flux was improved several folds. The enhanced flux was attributed to the higher surface porosity and wider finger-like voids in the cross-section. The thin PET fabric with larger porosity was able to maintain a consistent toughness simultaneously; thus it is recommended as a support material for this blended membrane.

Preparation, characterisation and critical flux determination of graphene oxide blended polysulfone (PSf) membranes in an MBR system.

Science.gov (United States)

Ravishankar, Harish; Roddick, Felicity; Navaratna, Dimuth; Jegatheesan, Veeriah

2018-05-01

Microfiltration membranes having different blends of graphene-oxide (GO) (0-1 wt%) and Polysulfone (PSf) (15-20 wt%) were prepared using the classical non-solvent induced phase inversion process. The prepared membranes were characterised for their structural morphology, surface properties, mechanical strength, porosity and pure water flux. Based on the initial characterisation results, four membranes (15 wt% PSf, 15 wt% PSf + 0.25 wt% GO, 15 wt% PSf + 1 wt% GO and 20 wt% PSf + 1 wt% GO) were chosen for critical flux study, that was conducted using flux-step method in a lab scale MBR system. In order to study the application potential of GO blended membranes, the critical flux of each membrane was evaluated in two operational modes i.e., continuous and intermittent modes with backwash. The membranes with maximal GO concentration (15 wt% PSf + 1 wt% GO and 20 wt% PSf + 1 wt% GO) showed higher critical flux (16.5, 12.8 L/m 2 h and 19, 15 L/m 2 h for continuous and intermittent mode, respectively). It was observed that the operational modes did not have a significant effect on the critical flux of the membranes with low GO concentration (15 wt% PSf and 15 wt% PSf + 0.25 wt% GO), indicating a minimal of 1 wt% GO was required for an observable effect that favoured intermittent mode of operation. Through these results, ideal operating condition was arrived (i.e., flux maintained at 6.4 L/m 2 h operated under intermittent mode) and the membranes 15 wt% PSf and 15 wt% PSf + 1 wt% GO were studied for their long-term operation. The positive effect of GO on filtration time, cleaning frequency and against fouling was demonstrated through long term TMP profile of the membranes, indicating the suitability of GO blended membrane for real time wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Proton-conducting membrane based on epoxy resin-poly(vinyl alcohol)-sulfosuccinic acid blend and its nanocomposite with sulfonated multiwall carbon nanotubes for fuel-cell application

Science.gov (United States)

Kakati, Nitul; Das, Gautam; Yoon, Young Soo

2016-01-01

A blend of poly(vinyl alcohol) (PVA) with diglycidyl ether of bisphenol-A (DGB) in the presence of sulfosuccinic acid (SSA) was investigated as hydrolytically-stable proton-conducting membrane. The PVA modification was carried out by varying the DGB:SSA ratio (20:20, 10:20, and 5:20). A nanocomposite of the blend (20:20) was prepared with sulfonated multiwall carbon nanotubes (viz., 1, 3 and 5 wt%). The water uptake behavior and the proton conductivity of the prepared membranes were evaluated. The ionic conductivity of the membranes and the water uptake behavior depended on the s-MWCNT and the DGB contents. The ionic conductivity showed an enhancement for the blend and for the nanocomposite membrane as compared to the pristine polymer.

Preparation and characterization of polymer blend based on sulfonated poly (ether ether ketone) and polyetherimide (SPEEK/PEI) as proton exchange membranes for fuel cells

Energy Technology Data Exchange (ETDEWEB)

Hashim, Nordiana; Ali, Ab Malik Marwan [Ionic Material and Devices Research Laboratory, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Lepit, Ajis; Rasmidi, Rosfayanti [Faculty of Applied Sciences, Universiti Teknologi MARA Sabah, Beg Berkunci 71, 88997 Kota Kinabalu (Malaysia); Subban, Ri Hanum Yahaya [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Yahya, Muhd Zu Azhan [Faculty of Defence Science & Technology, Universiti Pertahanan Nasional Malaysia, 57000 Kuala Lumpur (Malaysia)

2015-08-28

Blends of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared in five different weight ratios using N-methyl-2-pyrrolidone (NMP) as solvent by the solution cast technique. The degree of sulfonation (DS) of the sulfonated PEEK was determined from deuterated dimethyl sulfoxide (DMSO-d{sub 6}) solution of the purified polymer using {sup 1}H NMR method. The properties studied in the present investigation includes conductivity, water uptake, thermal stability and structure analysis of pure SPEEK as well as SPEEK-PEI polymer blend membranes. The experimental results show that the conductivity of the membranes increased with increase in temperature from 30 to 80°C, except for that of pure SPEEK membrane which increased with temperature from 30 to 60°C while its conductivity decreased with increasing temperature from 60 to 80°C. The conductivity of 70wt.%SPEEK-30wt.%PEI blend membrane at 80% relative humidity (RH) is found to be 1.361 × 10{sup −3} Scm{sup −1} at 30°C and 3.383 × 10{sup −3} Scm{sup −1} at 80°C respectively. It was also found that water uptake and thermal stability of the membranes slightly improved upon blending with PEI. Structure analysis was carried out using Fourier Transform Infrared (FTIR) spectroscopy which revealed considerable interactions between sulfonic acid group of SPEEK and imide groups of PEI. Modification of SPEEK by blending with PEI shows good potential for improving the electrical and physical properties of proton exchange membranes.

Preparation of PLLA/PMMA and PLLA/PS binary blend nanoparticles by incorporation of PLLA in methyl methacrylate or styrene miniemulsion homopolymerization

Directory of Open Access Journals (Sweden)

Luana Becker Peres

2015-02-01

Full Text Available Miniemulsion homopolymerization reactions of methyl methacrylate (MMA and styrene (STY using poly(L-lactide as co-stabilizer were carried out in order to prepare poly(L-lactide/poly(methyl methacrylate (PLLA/PMMA and poly(L-lactide/polystyrene (PLLA/PS binary blend nanoparticles. The effect of PLLA concentration on methyl methacrylate (MMA and styrene (STY homopolymerization reactions was evaluated. It was found that the incorporation of PLLA resulted on acceleration of MMA and STY homopolymerization reactions and led to a molar mass increase of up to 70% for PS in PLLA/PS blend nanoparticles in relation to those prepared without PLLA, which can be attributed to an increase of reaction loci viscosity (gel effect. PLLA also acted as an efficient co-stabilizer, since it was able to retard diffusional degradation of droplets when no other kind of co-stabilizer was used. Two isolated Tgs were found in both PLLA/PMMA and PLLA/PS blend nanoparticles which can be associated to blend immiscibility. TEM images corroborate these results, suggesting that immiscible PLLA/PMMA and PLLA/PS blend nanoparticles could be formed with two segregated phases and core-shell morphology.

Matrimid®/polysulfone blend mixed matrix membranes containing ZIF-8 nanoparticles for high pressure stability in natural gas separation

NARCIS (Netherlands)

Shahid, S.; Nijmeijer, K.

2017-01-01

Plasticization is of important concern in high pressure natural gas separation. Majority of the pure polymers and MOF-MMM systems suffer from plasticization at low pressures. Combination of polymer blending and MMM approach could lead to plasticization resistant membranes with improved membrane

Improvement in silicon-containing sulfonated polystyrene/acrylate membranes by blending and crosslinking

International Nuclear Information System (INIS)

Zhong Shuangling; Cui Xuejun; Dou Sen; Liu Wencong; Gao Yan; Hong Bo

2010-01-01

Silicon-containing sulfonated polystyrene/acrylate-poly(vinyl alcohol) (Si-sPS/A-PVA) and Si-sPS/A-PVA-phosphotungstic acid (Si-sPS/A-PVA-PWA) composite membranes were fabricated by solution blending and physical and chemical crosslinking methods to improve the properties of silicon-containing sulfonated polystyrene/acrylate (Si-sPS/A) membranes. FTIR spectra clearly show the existence of various interactions and a crosslinked silica network in composite membranes. The potential of the composites to act as proton exchange membranes in direct methanol fuel cells (DMFCs) was assessed by studying their thermal and hydrolytic stability, swelling, methanol diffusion coefficient, proton conductivity and selectivity. TGA measurements show that the composite membranes possess good thermal stability up to 190 o C, satisfying the requirement for fuel cell operation. Compared to the unmodified membrane, the composites exhibit less swelling and a superior methanol barrier. Most importantly, all of the composite membranes have significantly lower methanol diffusion coefficients and significantly higher selectivity than those of Nafion 117. The Si-sPS/A-20PVA-20PWA membrane is the best applicant for use in DMFCs because it exhibits an optimized selectivity value (5.93 x 10 5 Ss cm -3 ) that is approximately 7.8 times of that of the unmodified membrane and is 27.8 times higher than that of Nafion 117.

Morphological, rheological and mechanical characterization of polypropylene nanocomposite blends.

Science.gov (United States)

Rosales, C; Contreras, V; Matos, M; Perera, R; Villarreal, N; García-López, D; Pastor, J M

2008-04-01

In the present work, the effectiveness of styrene/ethylene-butylene/styrene rubbers grafted with maleic anhydride (MA) and a metallocene polyethylene (mPE) as toughening materials in binary and ternary blends with polypropylene and its nanocomposite as continuous phases was evaluated in terms of transmission electron microscopy (TEM), scanning electron microscopy (SEM), oscillatory shear flow and dynamic mechanical thermal analysis (DMA). The flexural modulus and heat distortion temperature values were determined as well. A metallocene polyethylene and a polyamide-6 were used as dispersed phases in these binary and ternary blends produced via melt blending in a corotating twin-screw extruder. Results showed that the compatibilized blends prepared without clay are tougher than those prepared with the nanocomposite of PP as the matrix phase and no significant changes in shear viscosity, melt elasticity, flexural or storage moduli and heat distortion temperature values were observed between them. However, the binary blend with a nanocomposite of PP as matrix and metallocene polyethylene phase exhibited better toughness, lower shear viscosity, flexural modulus, and heat distortion temperature values than that prepared with polyamide-6 as dispersed phase. These results are related to the degree of clay dispersion in the PP and to the type of morphology developed in the different blends.

CO2/CH4 Separation via Polymeric Blend Membrane

Directory of Open Access Journals (Sweden)

H. Sanaeepur

2013-01-01

Full Text Available CO2/CH4 gas separation is a very important applicatable process in upgrading the natural gas and landfil gas recovery. In this work, to investigate the membrane separation process performance, the gas permeation results andCO2/CH4 separation characteristics of different prepared membranes (via blending different molecular weights of polyethylene glycol (PEG as a modifier with acrylonitrile-butadiene-styrene (ABS as a backbone structure have been studied. Furthermore, SEM analysis was carried out for morphological investigations. The effect of PEG content on gas transport properties on the selected sample was also studied. The effect of pressure on CO2 permeation was examined and showed that at the pressure beyond 4 bar, permeability is not affected by pressure. The results showed that more or less in all cases, incorporation of PEG molecules without any significant increase in CH4 permeability increases the CO2/CH4 selectivity. From the view point of gas separation applications the resultant data are within commercial attractive range

Properties, degradation and high temperature fuel cell test of different types of PBI and PBI blend membranes

DEFF Research Database (Denmark)

Li, Qingfeng; Rudbeck, Hans Christian; Chromik, Andreas

2010-01-01

Polybenzimidazoles (PBIs) with synthetically modified structures and their blends with a partially fluorinated sulfonated aromatic polyether have been prepared and characterized for high temperature proton exchange membrane fuel cells. Significant improvement in the polymer chemical stability...

Laboratory Evaluation of Synthetic Blends of l-(+)-Lactic Acid, Ammonia, and Ketones As Potential Attractants For Aedes aegypti.

Science.gov (United States)

Venkatesh, P M; Sen, A

2017-12-01

Attraction of Aedes aegypti to various binary, trinary, and quaternary blends of lactic acid and ketones with or without ammonia was studied using a dual choice olfactometer. A dose dependent attraction was observed in cases of single compounds where cyclopentanone attracted the highest percentage (36.9 ± 1.8%) of Ae. aegypti when tested alone. No significant difference was observed between the attraction levels of trinary and binary blends of lactic acid and acetone or butanone when tested against clear air. However, in competitive bioassays, the trinary blend of lactic acid, acetone, and butanone was significantly preferred over binary blends of individual compounds ( P lactic acid. However, acetylacetone acted as an attraction inhibitor when blended with other compounds. Cyclopentanone was attractive, but enhancement of attraction was not observed when blended with other components. Addition of ammonia to binary or trinary blends of lactic acid, acetone, and/or butanone did not increase the attraction significantly. In competitive bioassays, the blends containing ammonia were significantly preferred over the blends lacking ammonia ( P lactic acid, ammonia, acetone, and butanone was most attractive (65 ± 1.5%) and preferred blend of all other combinations.

Synchrotron SAXS studies on morphology formation in a binary blend of poly(ε-caprolactone) homopolymer and poly(ε-caprolactone)-block-polybutadiene copolymer

International Nuclear Information System (INIS)

Akaba, Michiaki; Nojima, Shuichi

2005-01-01

The process of morphology formation in a binary blend of poly(ε-caprolactone) homopolymer (PCL) and poly(ε-caprolactone)-block-polybutadiene copolymer (PCL-b-PB) has been investigated by synchrotron small-angle X-ray scattering (SR-SAXS). This blend shows an UCST-type phase separation and the crystallization of PCL chains (i.e., PCL and PCL blocks in PCL-b-PB) at a same temperature range, so that these two factors may work simultaneously to yield a complicated morphology formation. When the weight fraction of PCL (φ PCL ) is small (φ PCL PCL > 0.8), the blend can directly be quenched into crystallization temperatures without passing through the UCST region. Time-resolved SAXS curves in this case show that overall morphology formation is driven by the crystallization of PCL chains, where a crystallized PCL region always coexists with a crystallized PCL-b-PB region and the volume ratio of two regions is constant throughout. (author)

Ion transport property studies on PEO-PVP blended solid polymer electrolyte membranes

International Nuclear Information System (INIS)

Chandra, Angesh; Agrawal, R C; Mahipal, Y K

2009-01-01

The ion transport property studies on Ag + ion conducting PEO-PVP blended solid polymer electrolyte (SPE) membranes, (1 - x)[90PEO : 10AgNO 3 ] : xPVP, where x = 0, 1, 2, 3, 5, 7, 10 (wt%), are reported. SPE films were caste using a novel hot-press technique instead of the traditional solution cast method. The conventional solid polymeric electrolyte (SPE) film, (90PEO : 10AgNO 3 ), also prepared by the hot-press method and identified as the highest conducting composition at room temperature on the basis of PEO-AgNO 3 -salt concentration dependent conductivity studies, was used as the first-phase polymer electrolyte host into which PVP were dispersed as second-phase dispersoid. A two-fold conductivity enhancement from that of the PEO host could be achieved at room temperature for PVP blended SPE film composition: 98(90PEO : 10AgNO 3 ) : 2PVP. This has been referred to as optimum conducting composition (OCC). The formation of SPE membranes and material characterizations were done with the help of the XRD and DSC techniques. The ion transport mechanism in this SPE OCC has been characterized with the help of basic ionic parameters, namely ionic conductivity (σ), ionic mobility (μ), mobile ion concentration (n) and ionic transference number (t ion ). Solid-state polymeric batteries were fabricated using OCC as electrolyte and the cell-potential discharge characteristics were studied under different load conditions.

Novel proton exchange membrane based on crosslinked poly(vinyl alcohol) for direct methanol fuel cells

Science.gov (United States)

Liu, Chien-Pan; Dai, Chi-An; Chao, Chi-Yang; Chang, Shoou-Jinn

2014-03-01

In this study, we report the synthesis and the characterization of poly (vinyl alcohol) based proton conducting membranes. In particular, we describe a novel physically and chemically PVA/HFA (poly (vinyl alcohol)/hexafluoroglutaric acid) blending membranes with BASANa (Benzenesulfonic acid sodium salt) and GA (Glutaraldehyde) as binary reaction agents. The key PEM parameters such as ion exchange capacity (IEC), water uptake, proton conductivity, and methanol permeability were controlled by adjusting the chemical composition of the membranes. The IEC value of the membrane is found to be an important parameter in affecting water uptake, conductivity as well as the permeability of the resulting membrane. Plots of the water uptake, conductivity, and methanol permeability vs. IEC of the membranes show a distinct change in the slope of their curves at roughly the same IEC value which suggests a transition of structural changes in the network. The proton conductivities and the methanol permeability of all the membranes are in the range of 10-3-10-2 S cm-1 and 10-8-10-7 cm2 s-1, respectively, depending on its binary crosslinking density, and it shows great selectivity compared with those of Nafion®-117. The membranes display good mechanical properties which suggest a good lifetime usage of the membranes applied in DMFCs.

Unimpeded permeation of water through biocidal graphene oxide sheets anchored on to 3D porous polyolefinic membranes

Science.gov (United States)

Mural, Prasanna Kumar S.; Jain, Shubham; Kumar, Sachin; Madras, Giridhar; Bose, Suryasarathi

2016-04-01

3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and hot-pressed samples revealed a clear picture as to how the morphology develops and coarsens over a function of time during post-processing operations like compression molding. The coarsening of PE/PEO blends was traced using X-ray micro-computed tomography and scanning electron microscopy (SEM) of annealed blends at different times. It is now understood from X-ray micro-computed tomography that by the addition of a compatibilizer (here lightly maleated PE), a stable morphology can be visualized in 3D. In order to anchor biocidal graphene oxide sheets onto these 3D porous membranes, the PE membranes were chemically modified with acid/ethylene diamine treatment to anchor the GO sheets which were further confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and surface Raman mapping. The transport properties through the membrane clearly reveal unimpeded permeation of water which suggests that anchoring GO on to the membranes does not clog the pores. Antibacterial studies through the direct contact of bacteria with GO anchored PE membranes resulted in 99% of bacterial inactivation. The possible bacterial inactivation through physical disruption of the bacterial cell wall and/or reactive oxygen species (ROS) is discussed herein. Thus this study opens new avenues in designing polyolefin based antibacterial 3D porous membranes for water purification.3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and

Modification of PSf/SPSf Blended Porous Support for Improving the Reverse Osmosis Performance of Aromatic Polyamide Thin Film Composite Membranes

Directory of Open Access Journals (Sweden)

Li-Fen Liu

2018-06-01

Full Text Available In this study, modification of polysulfone (PSf/sulfonated polysulfone (SPSf blended porous ultrafiltration (UF support membranes was proposed to improve the reverse osmosis (RO performance of aromatic polyamide thin film composite (TFC membranes. The synergistic effects of solvent, polymer concentration, and SPSf doping content in the casting solution were investigated systematically on the properties of both porous supports and RO membranes. SEM and AFM were combined to characterize the physical properties of the membranes, including surface pore natures (porosity, mean pore radius, surface morphology, and section structure. A contact angle meter was used to analyze the membrane surface hydrophilicity. Permeate experiments were carried out to evaluate the separation performances of the membranes. The results showed that the PSf/SPSf blended porous support modified with 6 wt % SPSf in the presence of DMF and 14 wt % PSf had higher porosity, bigger pore diameter, and a rougher and more hydrophilic surface, which was more beneficial for fabrication of a polyamide TFC membrane with favorable reverse osmosis performance. This modified PSf/SPSf support endowed the RO membrane with a more hydrophilic surface, higher water flux (about 1.2 times, as well as a slight increase in salt rejection than the nascent PSf support. In a word, this work provides a new facile method to improve the separation performance of polyamide TFC RO membranes via the modification of conventional PSf porous support with SPSf.

Film-forming properties of castor oil polyol ester blends in elastohydrodynamic conditions

Science.gov (United States)

The viscosities and elastohydrodynamic (EHD) film thickness properties of binary blends of castor oil with polyol esters were determined experimentally. Predicted blend viscosity was calculated from the viscosity of the pure blend components. Measured viscosity values were closer to the values pre...

A study on the combustion behaviour of coal blends

Energy Technology Data Exchange (ETDEWEB)

Rubiera, F.; Fuente, E.; Arenillas, A.; Pis, J.J. [Instituto Nacional del Carbon, Oviedo (Spain)

1999-07-01

Combustion behaviour of four coals of varying rank and their binary blends was studied using temperature programmed combustion tests, and thermogravimetric analysis. Characteristic parameters could not be predicted from the weight percentage of individual coals in the blend. 6 refs., 4 figs., 1 tab.

POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

DEFF Research Database (Denmark)

2001-01-01

A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes....... With the thermally resistant polymer, e.g., polybenzimidazole or a mixture of polybenzimidazole and other thermoplastics as binder, the carbon-supported noble metal catalyst is tape-cast onto a hydrophobic supporting substrate. When doped with an acid mixture, electrodes are assembled with an acid doped solid...

RELATIONSHIP BETWEEN FLASH POINTS OF SOME BINARY ...

African Journals Online (AJOL)

B. S. Chandravanshi

Miscellaneous binary blends containing solvent neutral-150 (SN-150), ... viscosity, the flash point test has always been a standard part of a lubricant's specification. ... between structure and flash points of organic compounds [5-12] and fuels [13, 14]. ... in binary mixtures, the gaps between flash points would be high enough.

Development of wet-dry reversible reverse osmosis membrane with high performance from cellulose acetate and cellulose triactate blend

NARCIS (Netherlands)

Vasarhelyi, K.; Ronner, J.A.; Mulder, M.H.V.; Smolders, C.A.

1987-01-01

Wet-dry reversible membrane were prepared bt a two-step coagulation procedure. A cast film containing a blend of cellulose triacetate as polymers, dioxane and acetone as solvents and maleic acid and methanol as additives was immersed consecutively in two aqueous coagulation baths, the first bath

Tailoring the mechanical and biodegradable properties of binary blends of biomedical thermoplastic elastomer.

Science.gov (United States)

Ang, Hui Ying; Chan, Jingni; Toong, Daniel; Venkatraman, Subbu S; Chia, Sing Joo; Huang, Ying Ying

2018-03-01

Blending polymers with complementary properties capitalizes on the inherent advantages of both components, making it possible to tailor the behaviour of the resultant material. A polymer blend consisting of an elastomer and thermoplastic can help to improve the mechanical integrity of the system without compromising on its processibility. A series of blends of biodegradable Poly(L-lactide-co-ɛ-caprolactone) (PLC) and Poly-(l,l-lactide-co-glycolic acid) (PLLGA), and PLC with Poly-(d,l-lactide-co-glycolic acid) (PDLLGA) were evaluated as a potential material for a biodegradable vesicourethral connector device. Based on the Tg of the blends, PLC/PLLGA formed an immiscible mixture while PLC/PDLLGA resulted in a compatible blend. The results showed that with the blending of PLC, the failure mode of PLLGA and PDLLGA changed from brittle to ductile fracture, with an significant decreas in tensile modulus and strength. SEM images demonstrated the different blend morphologies of different compositions during degradation. Gel Permeation Chromatography (GPC) and mechanical characterization revealed the degradation behaviour of the blends in this order (fastest to slowest): PDLLGA and PLC/PDLLGA blends > PLLGA and PLC/PLLGA blends > PLC. The PLC/PLLGA (70:30) blend was recommended as a suitable for the vesicourethral connector device application, highlighting the tailoring of blends to achieve a desired mechanical performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differential regulation of fatty acid biosynthesis in two Chlorella species in response to nitrate treatments and the potential of binary blending microalgae oils for biodiesel application.

Science.gov (United States)

Cha, Thye San; Chen, Jian Woon; Goh, Eng Giap; Aziz, Ahmad; Loh, Saw Hong

2011-11-01

This study was undertaken to investigate the effects of different nitrate concentrations in culture medium on oil content and fatty acid composition of Chlorella vulgaris (UMT-M1) and Chlorella sorokiniana (KS-MB2). Results showed that both species produced significant higher (pdifferentially regulated fatty acid accumulation patterns in response to nitrate treatments at early stationary growth phase. Their potential use for biodiesel application could be enhanced by exploring the concept of binary blending of the two microalgae oils using developed mathematical equations to calculate the oil mass blending ratio and simultaneously estimated the weight percentage (wt.%) of desirable fatty acid compositions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Concentration fluctuations in miscible polymer blends: Influence of temperature and chain rigidity

International Nuclear Information System (INIS)

Dudowicz, Jacek; Freed, Karl F.; Douglas, Jack F.

2014-01-01

In contrast to binary mixtures of small molecule fluids, homogeneous polymer blends exhibit relatively large concentration fluctuations that can strongly affect the transport properties of these complex fluids over wide ranges of temperatures and compositions. The spatial scale and intensity of these compositional fluctuations are studied by applying Kirkwood-Buff theory to model blends of linear semiflexible polymer chains with upper critical solution temperatures. The requisite quantities for determining the Kirkwood-Buff integrals are generated from the lattice cluster theory for the thermodynamics of the blend and from the generalization of the random phase approximation to compressible polymer mixtures. We explore how the scale and intensity of composition fluctuations in binary blends vary with the reduced temperature τ ≡ (T − T c )/T (where T c is the critical temperature) and with the asymmetry in the rigidities of the components. Knowledge of these variations is crucial for understanding the dynamics of materials fabricated from polymer blends, and evidence supporting these expectations is briefly discussed

A quasi-direct methanol fuel cell system based on blend polymer membrane electrolytes

DEFF Research Database (Denmark)

Li, Qingfeng; Hjuler, Hans Aage; Hasiotis, C.

2002-01-01

, compared to less than 100 ppm CO for the Nafion-based technology at 80degrees C. The high CO tolerance makes it possible to use the reformed hydrogen directly from a simple methanol reformer without further CO removal. That both the fuel cell and the methanol reformer operate at temperatures around 200......On the basis of blend polymer electrolytes of polybenzimidazole and sulfonated polysulfone, a polymer electrolyte membrane fuel cell was developed with an operational temperature up to 200degrees C. Due to the high operational temperature, the fuel cell can tolerate 1.0-3.0 vol % CO in the fuel...

Properties of PET/PLA Electrospun Blends

Science.gov (United States)

Li, Kevin; Cebe, Peggy

2012-02-01

Electrospun membranes were fabricated from poly(ethylene terephthalate), PET, co-spun with poly(lactic acid), PLA. The PLA contained 2% of the D-isomer, which served to limit the overall degree of crystallinity. Membranes were deposited from blended solutions of PET/PLA in hexafluoroisopropanol. The PET/PLA composition ranged from 0/100, 75/25, 50/50, 25/75, and 100/0. Electrospun membranes were made using either a static flat plate or a rotating wheel as the counter electrode, yielding unoriented mats or highly oriented tapes, respectively. We report on our investigation of the crystallinity, crystal perfection, and mechanical properties of these materials using differential scanning calorimetry, wide and small angle X-ray scattering, and dynamic mechanical analysis. In particular, we study the ability of one blend component (PET) to crystallize in the presence of existing crystals of the second blend component (PLA) which crystallizes first and at a lower temperature than PET.

Modelling of NO formation in the combustion of coal blends

Energy Technology Data Exchange (ETDEWEB)

Arenillas, A.; Backreedy, R.I.; Jones, J.M.; Pis, J.J.; Pourkashanian, M.; Rubiera, F.; Williams, A. [CSIC, Instituto Nacional del Carbon, Oviedo (Spain)

2002-03-01

Coal blending is becoming of increasing importance in power stations firing pulverised coal as a result of increasing competition, stricter emission legislation and is an attractive way of improving plant economic and combustion performance. Presently, the two general methods used by power station operators to assess or predict the performance of an unknown coal blend to be fired in power station boilers are by the use of experimental large scale rig tests or correlation indices derived from experience of firing other coal blends in the power station environment. The first is expensive and the second is of doubtful accuracy in some cases. This paper evaluates the application of mathematical modelling of the combustion of a series of binary coal blends in the test situation of a drop tube reactor to predict the NO emissions and degree of char burnout. Its applicability to low NOx burners used in power stations is discussed and it is concluded that present mathematical coal combustion models are not developed sufficiently to enable an adequate description of the binary blends and the physical and chemical processes, which may include interactions, during combustion of the blend. This means that accurate predictions cannot be made. 20 refs., 4 figs., 5 tabs.

Sulfonated PEEK and fluorinated polymer based blends for fuel cell applications: Investigation of the effect of type and molecular weight of the fluorinated polymers on the membrane's properties

Energy Technology Data Exchange (ETDEWEB)

Inan, Tuelay Y.; Dogan, Hacer; Unveren, Elif E. [The Scientific and Technological Research Council of Turkey (TUBITAK), Marmara Research Center, Chemistry Institute, 41470 Gebze, Kocaeli (Turkey); Eker, Ersoy [Tuerk Demirdoekuem Fabrikalari A.S., 11300 Bozueyuek, Bilecik (Turkey)

2010-11-15

This work clearly demonstrates the effect of the type and molecular weight of the fluorinated polymer of SPEEK/Fluorinated polymer blends for low temperature (<80 C) Fuel Cell Applications. Comparisons with trademarks (e.g., Nafion {sup registered}) suggests that the membranes we have prepared in this study have good compatibility in all application respects. Membranes were prepared by solution casting method from four different fluorinated polymers; poly (vinylidene fluoride) with three different molecular weights (PVDF, M{sub w}: 180.000, M{sub w}: 275.000, M{sub w}: 530.000); Poli(vinylidene fluoride-co-Hexafluoro propylen) (PVDF-HFP M{sub n}:130.000) and sulfonated poly(ether ether ketone) (SPEEK) with sulfonation degree (SD) of 70. The sulfonation degree (SD) of SPEEK was determined by FTIR, {sup 1}H NMR and ion exchange capacity (IEC) measurements. Thermo-oxidative stability and proton conductivity of the membranes were determined by using thermal gravimetric analysis (TGA) and BT-512 BekkTech membrane test systems, respectively. Chemical degradation of SPEEK membranes was investigated via Fenton test. The morphology of the membranes were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Water uptake and proton conductivity values decreased with the addition of fluorinated polymers (PVDF, PVDF-HFP) as expected, but proton conductivity values were still comparable to that of Nafion 117 {sup registered} membrane. Addition of fluorinated polymers improved chemical degradation of the blend membranes in all ratios while addition of PVDF-HFP to the SPEEK70 caused phase separations in all ratios. Methanol permeability value of SPEEK70/PVDF(M{sub w} = 275.000) blend membrane (3.13E-07 (cm{sup 2}/s)) was much lower than Nafion 117 {sup registered} (1.21E-06 (cm{sup 2}/s)). PVDF addition to the SPEEK polymers caused increase in elongation of the membranes. Increase in the molecular weight of the PVDF did not show any effect on

Composites and blends from biobased materials

Energy Technology Data Exchange (ETDEWEB)

Kelley, S.S. [National Renewable Energy Laboratory, Golden, CO (United States)

1995-05-01

The program is focused on the development of composites and blends from biobased materials to use as membranes, high value plastics, and lightweight composites. Biobased materials include: cellulose derivative microporous materials, cellulose derivative copolymers, and cellulose derivative blends. This year`s research focused on developing an improved understanding of the molecular features that cellulose based materials with improved properties for gas separation applications. Novel cellulose ester membrane composites have been developed and are being evaluated under a collaborative research agreement with Dow Chemicals Company.

Preparation and characterization of tragacanth-locust bean gum edible blend films.

Science.gov (United States)

Mostafavi, Fatemeh Sadat; Kadkhodaee, Rassoul; Emadzadeh, Bahareh; Koocheki, Arash

2016-03-30

The present work introduces the structure and physicomechanical properties of a novel blend film made from binary solutions of gum tragacanth (GT) and locust bean gum (LBG) at different mixing ratios. Apparent viscosities and surface tensions of individual and blend gum solutions were also investigated. The viscosity data indicated that there was a distinct synergism between the two gums at all mixing ratios. FTIR spectra showed the existence of noncovalent intermolecular interactions between gums. The surface tensions of binary solutions were significantly lower than those of individual gums which is advantageous for coating applications. All films had homogenous and smooth surface morphology and their transparency, water vapour barrier and mechanical properties were improved by incorporating LBG in blend. The results of this study suggest that GT-LBG blend film, owing to its desirable properties, has the potential to be used as a new degradable food packaging material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Poly(vinylbenzylchloride) Based Anion-Exchange Blend Membranes (AEBMs): Influence of PEG Additive on Conductivity and Stability.

Science.gov (United States)

Kerres, Jochen A; Krieg, Henning M

2017-06-16

In view of the many possible applications such as fuel cells and electrolysers, recent interest in novel anion exchange membranes (AEMs) has increased significantly. However, their low conductivity and chemical stability limits their current suitability. In this study, the synthesis and characterization of several three- and four-component anion exchange blend membranes (AEBMs) is described, where the compositions have been systematically varied to study the influence of the AEBM's composition on the anion conductivities as well as chemical and thermal stabilities under strongly alkaline conditions. It was shown that the epoxide-functionalized poly(ethylene glycol)s that were introduced into the four-component AEBMs resulted in increased conductivity as well as a marked improvement in the stability of the AEBMs in an alkaline environment. In addition, the thermal stability of the novel AEBMs was excellent showing the suitability of these membranes for several electrochemical applications.

Studies on as separation behaviour of polymer blending PI/PES hybrid mixed membrane: Effect of polymer concentration and zeolite loading

Directory of Open Access Journals (Sweden)

Ahmad Fauzi Ismail

2014-04-01

Full Text Available This study is performed primarily to investigate the effect of polymer concentration of polyimide/polyethersulfone (PI/PES blending on the gas separation performance of hybrid mixed matrix membrane. In this study, PI/ (PES–zeolite 4A mixed matrix membranes were casted using dry/wet phase inversion technique. The efefct of PI/PES concentrations and zeolite loading on the dope solution were investigated for gas separation performance. The results from the Field Emission Scanning Electron Microscopy (FESEM analysis confirmed that polymer concentration and zeolite loading was affected the morphology of membrane and gas separation performance. ‘Sieve-in-a-cage’ morphology observed the poor adhesion between polymer and zeolite at higher zeolite loading. The gas separation performance of the mixed matrix membranes were relatively higher compared to that of the neat polymeric membrane.

Crosslinked poly(vinyl alcohol)/sulfonated poly(ether ether ketone) blend membranes for fuel cell applications - Surface energy characteristics and proton conductivity

Energy Technology Data Exchange (ETDEWEB)

Kanakasabai, P.; Vijay, P.; Deshpande, Abhijit P.; Varughese, Susy [Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)

2011-02-01

Ionic polymers, their blends and composites are considered potential candidates for application as electrolytes in fuel cells. While developing new materials for membranes, it is important to understand the interactions of these electrolytic materials with electrodes/catalysts and with reactants/products. Some of these interactions can be understood by estimating the surface energy and wettability of the membrane materials. In this work, polyvinyl alcohol with varying degrees of sulfonation and its blend with sulfonated poly(ether ether ketone) are prepared and studied for their wettability characteristics using goniometry. The surface energy and its components are estimated using different approaches and compared. Properties such as the ion-exchange capacity, the proton conductivity and the water sorption/desorption behaviour are also investigated to understand the relationship with wettability and surface energy and its components. Among the different methods, the van Oss acid-base and the modified Berthelot approaches yield comparable estimates for the total surface energy. (author)

High power generation and COD removal in a microbial fuel cell operated by a novel sulfonated PES/PES blend proton exchange membrane

International Nuclear Information System (INIS)

Zinadini, S.; Zinatizadeh, A.A.; Rahimi, M.; Vatanpour, V.; Rahimi, Z.

2017-01-01

In this paper, firstly sulfonated polyethersulfone (SPES) was synthesized from polyethersulfone (PES) with sulfonation by chlorosulfonic acid as a sulfonating agent dissolved in concentrated sulfuric acid. PES/SPES blend proton exchange membranes (PEMs) were prepared at four different compositions with the non-solvent induced phase separation technique as alternative materials to Nafion membrane for application in a microbial fuel cell (MFC). The prepared PEMs were characterized by FTIR spectroscopy, AFM, SEM, contact angle, water uptake and oxygen permeability. Performances of the fabricated PEMs and commercial Nafion 117 were evaluated in a dual chamber MFC for treating of wastewater and electricity generation. Maximum generated power and current of the fabricated membranes were 58.726 mWm −2  at current density of 317.111 mAm −2 , while it was 45.512 mWm −2  at 228.673 mAm −2 for Nafion 117 at the similar experimental condition. The observed properties of low biofouling, low oxygen permeability, high power generation, high COD removal and coulombic efficiency (CE) indicated that the SPES membrane has potential to improve significantly the productivity of MFCs. - Highlights: • Sulfonated PES (SPES) was synthesized by chlorosulfonic acid in concentrated H 2 SO 4 . • PES/SPES blend proton exchange membranes (PEMs) were prepared for use in MFC. • Performance of PEMs and commercial Nafion 117 were tested to treat of wastewater. • Maximum generated power and current of SPES membrane was higher than Nafion 117.

Novel Pendant Benzene Disulfonic Acid Blended SPPO Membranes for Alkali Recovery: Fabrication and Properties.

Science.gov (United States)

Mondal, Abhishek N; Dai, Chunhua; Pan, Jiefeng; Zheng, Chunlei; Hossain, Md Masem; Khan, Muhammad Imran; Wu, Liang; Xu, Tongwen

2015-07-29

To reconcile the trade-off between separation performance and availability of desired material for cation exchange membranes (CEMs), we designed and successfully prepared a novel sulfonated aromatic backbone-based cation exchange precursor named sodium 4,4'-(((((3,3'-disulfo-[1,1'-biphenyl]-4,4'-diyl)bis(oxy)) bis(4,1-phenylene))bis(azanediyl))bis(methylene))bis(benzene-1,3-disulfonate) [DSBPB] from 4,4'-bis(4-aminophenoxy)-[1,1'-biphenyl]-3,3'-disulfonic acid [BAPBDS] by a three-step procedure that included sulfonation, Michael condensation followed by reduction. Prepared DSBPB was used to blend with sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) to get CEMs for alkali recovery via diffusion dialysis. Physiochemical properties and electrochemical performance of prepared membranes can be tuned by varying the dosage of DSBPB. All the thermo-mechanical properties like DMA and TGA were investigated along with water uptake (WR), ion exchange capacity (IEC), dimensional stability, etc. The effect of DSBPB was discussed in brief in connection with alkali recovery and ion conducting channels. The SPPO/DSBPB membranes possess both high water uptake as well as ion exchange capacity with high thermo-mechanical stability. At 25 °C the dialysis coefficients (UOH) appeared to be in the range of 0.0048-0.00814 m/h, whereas the separation factor (S) ranged from 12.61 to 36.88 when the membranes were tested for base recovery in Na2WO4/NaOH waste solution. Prepared membranes showed much improved DD performances compared to traditional SPPO membrane and possess the potentiality to be a promising candidate for alkali recovery via diffusion dialysis.

Blends of polyester ionomers with polar polymers: Interactions, reactions, and compatibilization

Science.gov (United States)

Boykin, Timothy Lamar

The compatibility of amorphous and semicrystalline polyester ionomers with various polar polymers (i.e., polyesters and polyamides) has been investigated for their potential use as minor component compatibilizers. The degree of compatibility (i.e., ranging from incompatible to miscible) between the polyester ionomers and the polar polymers was determined by evaluating the effect of blend composition on the melting behavior and phase behavior of binary blends. In addition, the origin of compatibility and/or incompatibility for each of the binary blends (i.e., polyamide/ionomer and polyester/ionomer) was determined by evaluating blends prepared by both solution and melt mixed methods. Subsequent to investigation of the binary blends, the effect of polyester ionomer addition on the compatibility of polyamide/polyester blends was investigated by evaluating the mechanical properties and phase morphology of ionomer compatibilized polyamide/polyester blends. Polyester ionomers (amorphous and semicrystalline) were shown to exhibit a high degree of compatibility (even miscibility) with polyamides, such as nylon 6,6 (N66). Compatibility was attributed to specific interactions between the metal counterion of the polyester ionomer and the amide groups of N66. The degree of compatibility (or miscibility) was shown to be dependent on the counterion type of the ionomer, with the highest degree exhibited by blends containing the divalent form of the polyester ionomers. Although polyester ionomers were shown to exhibit incompatibility with both poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), increasing the time of melt processing significantly enhanced the compatibility of the polyester ionomers with both PET and PBT. The observed enhancement in compatibility was attributed to ester-ester interchange between the polyester blend components, which was confirmed by NMR spectroscopy. The addition of polyester ionomers as a minor component compatibilizer (i

The pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 at high pressure: a mechanism for the zinc blende to cinnabar reconstructive phase transition

CERN Document Server

Kozlenko, D P; Ehm, L; Hull, S; Savenko, B N; Shchennikov, V V; Voronin, V I

2003-01-01

The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by x-ray and neutron powder diffraction at pressures up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. A phenomenological model of this reconstructive phase transition based on a displacement mechanism is proposed. Analysis of the geometrical relationship between the zinc blende and the cinnabar phases has shown that the possible order parameter for the zinc blende-cinnabar structural transformation is the spontaneous strain e sub 4. This assignment agrees with the previously observed high pressure behaviour of the elastic constants of some mercury chalcogenides.

Theory of polymer blends

International Nuclear Information System (INIS)

Curro, J.G.; Schweizer, K.S.

1989-01-01

We have recently developed a new theoretical approach to the study of polymer liquids. The theory is based on the ''reference interaction site model'' (RISM theory) of Chandler and Andersen, which has been successful in describing the structure of small molecule liquids. We have recently extended our polymer RISM theory to the case of polymer blends. In the present investigation we have applied this theory to two special binary blends: (1) the athermal mixture where we isolate structural effects, and (2) the isotopic mixture in which structurally identical polymer chains interact with dissimilar attractive interactions. By studying these two special cases we are able to obtain insights into the molecular factors which control the miscibility in polymer mixtures. 18 refs., 2 figs

Flexible and strong ternary blends of poly(vinyl chloride), poly(butylene adipate)and nanoparticle-plasticizers

OpenAIRE

Yin, Bo; Hakkarainen, Minna

2013-01-01

Multiple property enhancement was achieved for ternary blends of PVC, poly(butylene adipate) (PBA) plasticizer and PBA-grafted nanofillers as compared to ternary blends with untreated nanofillers. The blends with surface modified halloysite, kaolin or silicon dioxide nanofillers all exhibited higher stress at break and higher strain at break as compared to the corresponding composites with untreated nanoparticles. The strain at break was similar or improved compared to binary PVC/PBA blends. ...

Blends of caprolactam/caprolactone copolymers and chlorinated polymers

NARCIS (Netherlands)

Alberda van Ekenstein, G.O.R.; Deuring, H.; ten Brinke, G.; Ellis, T.S.

The phase behaviour of blends of chlorinated polyethylene, polyvinyl chloride (PVC) and chlorinated PVC with random copolymers of caprolactone and caprolactam has been investigated and the results correlated with a binary interaction model. The known miscibility of polycaprolactone in the

Development and characterization of polymeric membranes for water desalination

International Nuclear Information System (INIS)

Bresciani, Danusa; Guimaraes, Danilo H.; Santos, Diego K.M.; Brioude, Michel M.; Jose, Nadia M.; Prado, Luis A.S.A.

2009-01-01

This work reports a development of polymeric membranes for water desalination by reverse osmosis. The polyester was synthesized by the reaction between glycerol, and dicarboxylic acids, and was coded PAF. Cellulose acetate/PAF blends containing 10% and 30% of polyester PAF blends were prepared using compression molding. The materials were characterized by DRX, DSC, TGA and SEM techniques. The results blends showed good thermal resistance and thermal events due to the individual components of the blends. The membranes exhibited a good performance in comparison to the neat cellulose acetate membrane. The addition of PAF in the polyester composition of the polymeric blends caused a significant increase of the salt retention of the studied samples. (author)

Solution casting Nafion/polytetrafluoroethylene membrane for vanadium redox flow battery application

International Nuclear Information System (INIS)

Teng, Xiangguo; Sun, Cui; Dai, Jicui; Liu, Haiping; Su, Jing; Li, Faqiang

2013-01-01

Highlights: ► Nafion/polytetrafluoroethylene (PTFE) blend membranes were prepared by solution casting method. ► The blend membranes were tested for vanadium redox flow battery (VRB) application. ► The blend membranes show lower vanadium ion permeability than that of recast Nafion membrane. ► In VRB single cell test, the blend membrane shows superior performances than that of pure recast Nafion. -- Abstract: Solution casting method was adopted using Nafion and polytetrafluoroethylene (PTFE) solution to prepare Nafion/PTFE blend membranes for vanadium redox flow battery application. The physicochemical properties of the membranes were characterized by using water uptake, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal analysis (TA). The electrochemical properties of the membranes were examined by using electrochemical impedance spectroscopy (EIS) and single cell test. Despite the high miscibility of PTFE with Nafion, the addition of hydrophobic PTFE reduces the water uptake, ion exchange capacity (IEC) and conductivity of blend membranes. But PTFE can increase the crystallinity, thermal stability of Nafion/PTFE membranes and reduce the vanadium permeability. The blend membrane with PTFE (30 wt%, N 0.7 P 0.3 ) was chosen and investigated for VRB single cell test. The energy efficiency of this VRB with N 0.7 P 0.3 membrane was 85.1% at current density of 50 mA cm −2 , which was superior to that of recast Nafion (r-Nafion) membrane (80.5%). Self-discharge test shows that the decay of open circuit potential of N 0.7 P 0.3 membrane is much lower than that of r-Nafion membrane. More than 50 cycles charge–discharge test proved that the N 0.7 P 0.3 membrane possesses high stability in long time running. Chemical stabilities of the chosen N 0.7 P 0.3 membrane are further proved by soaking the membrane for 3 weeks in highly oxidative V(V) solution. All results suggest that the addition of PTFE is a simple and effective way to

Preparation and characterization of a novel PVDF ultrafiltration membrane by blending with TiO_2-HNTs nanocomposites

International Nuclear Information System (INIS)

Zeng, Guangyong; He, Yi; Yu, Zongxue; Zhan, Yingqing; Ma, Lan; Zhang, Lei

2016-01-01

Highlights: • A novel TiO_2-HNTs/PVDF ultrafiltration membrane was prepared. • TiO_2 dispersed well in membrane matrix by loading on the surface of HNTs. • The hydrophilicity of membrane was improved with the addition of TiO_2-HNTs. • TiO_2-HNTs/PVDF membranes showed good antifouling performance. - Abstract: Novel polyvinylidene fluoride (PVDF) ultrafiltration membranes were prepared by blending with different contents of titanium dioxide-halloysite nanotubes (TiO_2-HNTs) composites into the PVDF matrix. The effects of TiO_2-HNTs content on the membrane performances, such as hydrophilicity, rejection ratio and antifouling properties were investigated in detail. X-ray diffraction (XRD), thermo-gravimetric analyzer (TGA) and scanning electron microscope (SEM) analyses showed that TiO_2 was loaded on the surface of HNTs successfully and homogeneously by sol-gel method. The morphologies and microstructure of the membranes were characterized by SEM and atomic force microscopy (AFM). The contact angle (CA) tests indicated that the hydrophilicity of membranes was significantly increased with the addition of TiO_2-HNTs. The pure water flux of 3%TiO_2-HNTs/PVDF was increased by 264.8% and 35.6%, respectively, compared with pure PVDF membrane and 3%TiO_2/PVDF membrane, although the rejection of bovine serum albumin (BSA) was slightly decreased. More importantly, TiO_2-HNTs/PVDF membrane exhibited an excellent anti-fouling performance, which was attributed to the hydrophobic contaminants being resisted by hydrophilic nanoparticles. It can be expected that this work may provide some references to solve the dispersion of nanoparticle in the membrane and improve the anti-fouling performance of membrane in the field of wastewater treatment.

Modification of combustion behaviour and NO emissions by coal blending

Energy Technology Data Exchange (ETDEWEB)

Rubiera, Fernando; Arenillas, Ana; Arias, Borja; Pis, Jose J. [Department of Energy and Environment, Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

2002-06-20

Combustion profiles determined by TGA and experiments in a laminar entrained flow reactor (EFR) were used in this work to assess the relative combustion reactivities of different rank coals and their binary coal blends. The combustion behaviour of coal blends in TGA was greatly influenced by coal rank and the proportion of each component in the blend. Higher volatile coals exerted more influence in the low-temperature region and less reactive coals in the char combustion zone. The results in the EFR indicated that coal blends burnout and NO emissions show additivity in the case of similar nature coals. When one of the components was a high-rank coal, the burnout of the blend exhibited, in some cases, positive synergistic effects, while a clear deviation from linearity was found in NO emissions.

Positron annihilation lifetime study of interfaces in ternary polymer blends

International Nuclear Information System (INIS)

Meghala, D; Ramya, P; Pasang, T; Raj, J M; Ranganathaiah, C; Williams, J F

2013-01-01

A new method based on positron lifetime spectroscopy is developed to characterize individual interfaces in ternary polymer blends and hence determine the composition dependent miscibility level. The method owes its origin to the Kirkwood-Risemann-Zimm (KRZ) model for the evaluation of the hydrodynamic interaction parameters (α ij ) which was used successfully for a binary blend with a single interface. The model was revised for the present work for ternary polymer blends to account for three interfaces. The efficacy of this method is shown for two ternary blends namely poly(styrene-co-acrylonitrile)/poly (ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and polycaprolactone /poly(styrene-co-acrylonitrile)/poly(vinyl chloride) (PCL/SAN/PVC) at different compositions. An effective hydrodynamic interaction parameter, α eff , was introduced to predict the overall miscibility of ternary blends.

Miscibility of polymer blends with engineering models

DEFF Research Database (Denmark)

Vassilis, Harismiadis; van Bergen, A. R. D.; Goncalves, Ana Saraiva

1996-01-01

compared. The van der Waals equation of state was recently shown to accurately correlate and predict vapor-liquid and liquid-liquid equilibria for binary polymer/solvent solutions. In this work, it is demonstrated that it correlates the upper critical solution behavior of polymer blends with excellent...... accuracy using the usual mixing and combining rules and a single temperature- and composition-independent binary interaction parameter. This interaction parameter can be predicted via a generalized expression that uses only the pure component equation-of-state parameters. Using this generalized expression...

Incorporation of Human Recombinant Tropoelastin into Silk Fibroin Membranes with the View to Repairing Bruch’s Membrane

Directory of Open Access Journals (Sweden)

Audra M. A. Shadforth

2015-09-01

Full Text Available Bombyx mori silk fibroin membranes provide a potential delivery vehicle for both cells and extracellular matrix (ECM components into diseased or injured tissues. We have previously demonstrated the feasibility of growing retinal pigment epithelial cells (RPE on fibroin membranes with the view to repairing the retina of patients afflicted with age-related macular degeneration (AMD. The goal of the present study was to investigate the feasibility of incorporating the ECM component elastin, in the form of human recombinant tropoelastin, into these same membranes. Two basic strategies were explored: (1 membranes prepared from blended solutions of fibroin and tropoelastin; and (2 layered constructs prepared from sequentially cast solutions of fibroin, tropoelastin, and fibroin. Optimal conditions for RPE attachment were achieved using a tropoelastin-fibroin blend ratio of 10 to 90 parts by weight. Retention of tropoelastin within the blend and layered constructs was confirmed by immunolabelling and Fourier-transform infrared spectroscopy (FTIR. In the layered constructs, the bulk of tropoelastin was apparently absorbed into the initially cast fibroin layer. Blend membranes displayed higher elastic modulus, percentage elongation, and tensile strength (p < 0.01 when compared to the layered constructs. RPE cell response to fibroin membranes was not affected by the presence of tropoelastin. These findings support the potential use of fibroin membranes for the co-delivery of RPE cells and tropoelastin.

Controlling the Solidification of Organic Photovoltaic Blends with Nucleating Agents

KAUST Repository

Nekuda Malik, Jennifer A.; Treat, Neil D.; Abdelsamie, Maged; Yu, Liyang; Li, Ruipeng; Smilgies, Detlef-M.; Amassian, Aram; Hawker, Craig J.; Chabinyc, Michael L.; Stingelin, Natalie

2014-01-01

Blending fullerenes with a donor polymer for the fabrication of organic solar cells often leads to at least partial vitrification of one, if not both, components. For prototypical poly(3-hexylthiophene):fullerene blend, we show that the addition of a commercial nucleating agent, di(3,4-dimethyl benzylidene)sorbitol, to such binary blends accelerates the crystallization of the donor, resulting in an increase in its degree of crystallinity in as-cast structures. This allows manipulation of the extent of intermixing/ phase separation of the donor and acceptor directly from solution, offering a tool to improve device characteristics such as power conversion efficiency.

Controlling the Solidification of Organic Photovoltaic Blends with Nucleating Agents

KAUST Repository

Nekuda Malik, Jennifer A.

2014-11-20

Blending fullerenes with a donor polymer for the fabrication of organic solar cells often leads to at least partial vitrification of one, if not both, components. For prototypical poly(3-hexylthiophene):fullerene blend, we show that the addition of a commercial nucleating agent, di(3,4-dimethyl benzylidene)sorbitol, to such binary blends accelerates the crystallization of the donor, resulting in an increase in its degree of crystallinity in as-cast structures. This allows manipulation of the extent of intermixing/ phase separation of the donor and acceptor directly from solution, offering a tool to improve device characteristics such as power conversion efficiency.

Production of silk sericin/silk fibroin blend nanofibers

Directory of Open Access Journals (Sweden)

Zhang Xianhua

2011-01-01

Full Text Available Abstract Silk sericin (SS/silk fibroin (SF blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75 blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50 blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100 blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.

Development and characterization of acid-doped polybenzimidazole/sulfonated polysulfone blend polymer electrolytes for fuel cells

DEFF Research Database (Denmark)

Hasiotis, C.; Li, Qingfeng; Deimede, V.

2001-01-01

Polymeric membranes from blends of sulfonated polysulfones (SPSF) and polybenzimidazole (PBI) doped with phosphoric acid were developed as potential high-temperature polymer electrolytes for fuel cells and other electrochemical applications. The water uptake and acid doping of these polymeric...... membranes were investigated. Ionic conductivity of the membranes was measured in relation to temperature, acid doping level, sulfonation degree of SPSF, relative humidity, and blend composition. The conductivity of SPSF was of the order of 10/sup -3/ S cm/sup -1/. In the case of blends of PBI and SPSF...

Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

Energy Technology Data Exchange (ETDEWEB)

Li Jianhua, E-mail: jhli_2005@163.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Zhang Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China) and Institute of Biomedical Engineering, Chinese Academy of Medical Science, Peking Union Medical College, Tianjin 300192 (China)

2012-06-15

An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

International Nuclear Information System (INIS)

Li Jianhua; Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng; Zhang Qiqing

2012-01-01

An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

MICROENCAPSULATION OF TURMERIC OLEORESIN IN BINARY AND TERNARY BLENDS OF GUM ARABIC, MALTODEXTRIN AND MODIFIED STARCH

Directory of Open Access Journals (Sweden)

Diana Maria Cano-Higuita

2015-04-01

Full Text Available Spray-drying is a suitable method to obtain microencapsulated active substances in the powdered form, resulting in powders with improved protection against environmental factors as well as with higher solubility in water, as in the case of turmeric oleoresin. The present study investigated the spray-drying process of turmeric oleoresin microencapsulated with binary and ternary mixtures of different wall materials: gum Arabic, maltodextrin, and modified corn starch. A statistical simplex centroid experimental design was used considering the encapsulation efficiency, curcumin retention, process yield, water content, solubility, and particle morphology as the analyzed responses. Wall matrices containing higher proportions of modified starch and gum Arabic resulted in higher encapsulation efficiency and curcumin retention, whereas the process yield and water content increased with higher proportions of maltodextrin and gum Arabic, respectively. Regression models of the responses were obtained using a surface response method (ANOVA way, showing statistical values of R2 > 0.790. Also, mean analysis was carried out by Tukey's test, permitting to observe some statistical differences between the blends

Topological and morphological analysis of gamma rays irradiated chitosan-poly (vinyl alcohol) blends using atomic force microscopy

International Nuclear Information System (INIS)

Bhatt, Rinkesh; Bisen, D.S.; Bajpai, R.; Bajpai, A.K.

2017-01-01

In the present communication, binary blends of poly (vinyl alcohol) (PVA) and chitosan (CS) were prepared by solution cast method and the roughness parameters of PVA, native CS and CS-PVA blend films were determined using atomic force microscopy (AFM). Moreover, the changes in the morphology of the samples were also investigated after irradiation of gamma rays at absorbed dose of 1 Mrad and 10 Mrad for the scanning areas of 5×5 µm 2 , 10×10 µm 2 and 20×20 µm 2 . Amplitude, statistical and spatial parameters, including line, 3D and 2D image profiles of the experimental surfaces were examined and compared to un-irradiated samples. For gamma irradiated CS-PVA blends the larger waviness over the surface was found as compared to un-irradiated CS-PVA blends but the values of average roughness for both the films were found almost same. The coefficient of skewness was positive for gamma irradiated CS-PVA blends which revealed the presence of more peaks than valleys on the blend surfaces. - Highlights: • Binary polymer blends of chitosan and PVA were prepared. • Irradiation by gamma rays exhibited a significant change in surface morphology. • Various topographical and morphological parameters were investigated. • The prepared irradiated blends may find biomedical applications.

Preparation of poly(3-hydroxybutyrate)/carboxymethyl cellulose acetate butyrate blends using gel formation

International Nuclear Information System (INIS)

Gomes, A.L.; Rodrigues, G.V.; Goncalves, M.C.

2009-01-01

This study investigates poly(3-hydroxybutyrate) (PHB) gel formation with a binary combination of solvents and its use on the preparation of PHB and carboxymethyl cellulose acetate butyrate (CMCAB) blends. The gel preparation method was compared to a precipitation method followed by hot pressing. The results from DSC and X-ray diffractions showed that both methodologies produced blends with very similar thermal properties and crystallization behavior. Scanning electron microscopy indicated better homogeneity in gel formation blends. Apart from this, the gel formation methodology provided new ways to prepare immiscible blends with the advantage of using friendlier solvents. (author)

Exploration of permeability and antifouling performance on modified cellulose acetate ultrafiltration membrane with cellulose nanocrystals.

Science.gov (United States)

Lv, Jinling; Zhang, Guoquan; Zhang, Hanmin; Yang, Fenglin

2017-10-15

Cellulose nanocrystals (CNCs) were introduced into cellulose diacetate (CDA) matrix via immerged phase-inversion process, aiming to improve the filtration and antifouling performance of CNCs/CDA blending membrane. The effects of CNCs on membrane morphologies, hydrophilicity, permeability and antifouling property were investigated. Results showed that the incorporation of CNCs into CDA membrane could effectively enhance the permeability and antifouling property of CNCs/CDA blending membrane by optimizing membrane microstructure and improving membrane hydrophilicity. A high pure water flux of 173.8L/m 2 h was achieved for the CNCs/CDA blending membrane at 200KPa, which is 24 times that of the CDA membrane (7.2L/m 2 h). The bovine serum albumin (BSA) adsorption amount of the CNCs/CDA blending membrane decreased about 48% compared to that of the CDA membrane. Additionally, the CNCs/CDA blending membrane exhibited better antifouling performance with the flux recovery ratio (FRR) of 89.5% after three fouling cycles, compared to 59.7% for the CDA membrane. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation and characterization of a novel PVDF ultrafiltration membrane by blending with TiO{sub 2}-HNTs nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Zeng, Guangyong [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); He, Yi, E-mail: heyi@swpu.edu.cn [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Yu, Zongxue; Zhan, Yingqing; Ma, Lan [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Zhang, Lei, E-mail: zgc166929@sohu.com [College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, Sichuan 610500 (China)

2016-05-15

Highlights: • A novel TiO{sub 2}-HNTs/PVDF ultrafiltration membrane was prepared. • TiO{sub 2} dispersed well in membrane matrix by loading on the surface of HNTs. • The hydrophilicity of membrane was improved with the addition of TiO{sub 2}-HNTs. • TiO{sub 2}-HNTs/PVDF membranes showed good antifouling performance. - Abstract: Novel polyvinylidene fluoride (PVDF) ultrafiltration membranes were prepared by blending with different contents of titanium dioxide-halloysite nanotubes (TiO{sub 2}-HNTs) composites into the PVDF matrix. The effects of TiO{sub 2}-HNTs content on the membrane performances, such as hydrophilicity, rejection ratio and antifouling properties were investigated in detail. X-ray diffraction (XRD), thermo-gravimetric analyzer (TGA) and scanning electron microscope (SEM) analyses showed that TiO{sub 2} was loaded on the surface of HNTs successfully and homogeneously by sol-gel method. The morphologies and microstructure of the membranes were characterized by SEM and atomic force microscopy (AFM). The contact angle (CA) tests indicated that the hydrophilicity of membranes was significantly increased with the addition of TiO{sub 2}-HNTs. The pure water flux of 3%TiO{sub 2}-HNTs/PVDF was increased by 264.8% and 35.6%, respectively, compared with pure PVDF membrane and 3%TiO{sub 2}/PVDF membrane, although the rejection of bovine serum albumin (BSA) was slightly decreased. More importantly, TiO{sub 2}-HNTs/PVDF membrane exhibited an excellent anti-fouling performance, which was attributed to the hydrophobic contaminants being resisted by hydrophilic nanoparticles. It can be expected that this work may provide some references to solve the dispersion of nanoparticle in the membrane and improve the anti-fouling performance of membrane in the field of wastewater treatment.

Styrene-Based Copolymer for Polymer Membrane Modifications

OpenAIRE

Harsha Srivastava; Harshad Lade; Diby Paul; G. Arthanareeswaran; Ji Hyang Kweon

2016-01-01

Poly(vinylidene fluoride) (PVDF) was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffr...

Changes on the Solid Fat Content of Palm Oil/ Sunflower Oil Blends via Inter esterification

International Nuclear Information System (INIS)

Suria Ramli; Azwani Mohd Lazim; Siti Aishah Hasbullah

2013-01-01

Physicochemical characteristics of binary blends containing refined-deodorized-bleached palm oil (RBDPO) and sunflower oil (SFO) were studied before and after chemical inter esterification at different temperature (110 degree Celsius (CIE1) and 80 degree Celsius (CIE2)) using sodium methoxide as catalyst. Thirty-three samples with different ratios were analyzed for triacylglycerol (TAG) composition, fatty acid composition (FAC) and solid fat content (SFC) profile. Upon CIE, extensive rearrangements of fatty acids among triacylglycerol (TAG) were seen. Generally, CIE not induced enormous changes in the TAG compositions of ratio 8:2 and 5:5 of RBDPO:SFO blends. However, CIE induced enormous changes in the TAG compositions of the 9:1, 7:3, 6:4, 4:6, 3:7, 2:8 and 1:9 blends, which some of the TAGs were increasing while the other decreasing. These changes in TAG profiles resulted in some changes in the physical properties (especially SFC) of the blends. Generally, the SFC of inter esterified blend were decreased after CIE1 and increased after CIE2, except for sample 10:0, 8:2, 7:3, 5:5 and 9:1 which were decreased after CIE1 and CIE2. As a conclusion, CIE1 and CIE2 successfully changed the physicochemical characteristics of the binary blends. (author)

Selective removal of carbon dioxide from wet CO{sub 2}/H{sub 2} mixtures via facilitated transport membranes containing amine blends as carriers

Energy Technology Data Exchange (ETDEWEB)

Heydari Gorji, A. [Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran); Kargari, A. [Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran (Iran); Kaghazchi, T.

2009-01-15

The selective separation of carbon dioxide (CO{sub 2}) from a wet gaseous mixture of CO{sub 2}/H{sub 2} through facilitated transport membranes containing immobilized aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), ethylenediamine (EDA) and monoprotonated ethylenediamine (EDAH{sup +}) and their blends was experimentally investigated. The effect of CO{sub 2} partial pressure, amine concentration, feed side pressure and amine species on the CO{sub 2} and H{sub 2} permeances were studied. The CO{sub 2} permeability through amine solution membranes decreased with increasing CO{sub 2} feed partial pressure but the H{sub 2} permeance was almost independent of the H{sub 2} partial pressure. A comparison of experimental results showed that single or blended amines with low viscosity and a moderate equilibrium constant, i.e., large forward and reverse reaction rate of CO{sub 2}-amine, are suitable for effective separation of CO{sub 2}. The permeability of CO{sub 2} generally increased with an increase in amine concentration, although this increase may be compromised by the salting out effect and decrease in diffusivities of species. The results obtained indicated that CO{sub 2} permeance across a variety of amines are in the order of DEA (2 M)>MD(2M) >MD(1 M)>MEA(2 M) >MEA(4 M)>MD (4 M)>DEA (1 M)> DEA(4 M)>MEA (1 M) for various concentrations of MEA+DEA blend and are in the order of EDAH{sup +}(2 M)> DEA(2 M) >MH(2 M)>DH (2 M)>ED (2 M)>EDA (2 M)> MEA(2 M) for various blends of amine. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Thermal profiles, crystallization behaviors and microstructure of diacylglycerol-enriched palm oil blends with diacylglycerol-enriched palm olein.

Science.gov (United States)

Xu, Yayuan; Zhao, Xiaoqing; Wang, Qiang; Peng, Zhen; Dong, Cao

2016-07-01

To elucidate the possible interaction mechanisms between DAG-enriched oils, this study investigated how mixtures of DAG-enriched palm-based oils influenced the phase behavior, thermal properties, crystallization behaviors and the microstructure in binary fat blends. DAG-enriched palm oil (PO-DAGE) was blended with DAG-enriched palm olein (POL-DAGE) in various percentages (0%, 10%, 30%, 50%, 70%, 90%, 100%). Based on the observation of iso-solid diagram and phase diagram, the binary mixture of PO-DAGE/POL-DAGE showed a better compatibility in comparison with their corresponding original blends. DSC thermal profiles exhibited that the melting and crystallization properties of PO-DAGE/POL-DAGE were distinctively different from corresponding original blends. Crystallization kinetics revealed that PO-DAGE/POL-DAGE blends displayed a rather high crystallization rate and exhibited no spherulitic crystal growth. From the results of polarized light micrographs, PO-DAGE/POL-DAGE blends showed more dense structure with very small needle-like crystals than PO/POL. X-ray diffraction evaluation revealed when POL-DAGE was added in high contents to PO-DAGE, above 30%, β-polymorph dominated, and the mount of β' forms crystals was decreasing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enchansing the Ionic Purity of Hydrophilic Channels by Blending Fully Sulfonated Graft Copolymers with PVDF Homopolymer

DEFF Research Database (Denmark)

Nielsen, Mads Møller; Ching-Ching Yang, Ami; Jankova Atanasova, Katja

2013-01-01

The influence of tuning the ionic content of membranes by blending, as opposed to varying the degree of sulfonation, is evaluated. Membranes of fully sulfonated poly(vinylidene fluoride-co-chlorotrifluoroethylene)-g-poly(styrene sulfonic acid) blended with PVDF were prepared and investigated...

Preparation and characterization of blends containing silk fibroin and chitosan

International Nuclear Information System (INIS)

Moraes, Mariana A. de; Nogueira, Grinia M.; Weska, Raquel F.; Beppu, Marisa M.

2009-01-01

The aim of this study was to prepare and characterize blend membranes of silk fibroin and chitosan. Moreover, a conformation of fibroin to a more stable form induced by the addition of chitosan was verified. Blend membranes of fibroin/chitosan were prepared in different proportions and had their crystallinity, structural conformation and thermal stability characterized. The results of crystallographic analysis (XRD) indicated the tendency to higher structural organization caused by the addition of chitosan. FTIR showed that, mainly in a content of chitosan of only 25%, fibroin is present in a more stable form. Thermal analyzes indicate that fibroin is thermally stable and that when its proportion in the blend increases, the temperature in which the degradation is initiated also does so. (author)

Catalytic phosphonation of high performance polymers and POSS. Novel components for polymer blend and nanocomposite fuel cell membranes

Energy Technology Data Exchange (ETDEWEB)

Bock, T.R.

2006-10-15

Aim of this thesis was the preparation and evaluation of phosphonated high performance (HP) polyelectrolytes and polyhedral oligomeric silsesquioxanes (POSS) for polyelectrolyte membrane fuel cell (PEMFC) application. Brominated derivatives of the commercial high performance (HP) polymers poly(ethersulfone) (PES), poly(etheretherketone) (PEEK), poly(phenylsulfone) (PPSu), poly(sulfone) (PSU) and of octaphenyl-POSS of own production were phosphonated by Ni-catalysed Arbuzov reaction. Phosphonated PSU was cast into pure and blend films with sulfonated PEEK (s-PEEK) to investigate H+-conductivity, water uptake and film morphology. Blend films' properties were referenced to films containing unmodified blend partners. Solution-compounding of phosphonated octaphenyl-POSS and s-PEEK was used to produce novel nanocomposite films. An in-situ zirconisation method was assessed as convenient strategy for novel ionically crosslinked membranes of enhanced swelling resistance. Dibromo isocyanuric acid (DBI) and N-bromo succinimide (NBS) as brominating agents allowed polymer analogous preparation of the novel brominated PES and PEEK with precise reaction control. A random distribution of functional groups, i.e. polyelectrolytes' microstructural homogeneity was revealed as decisive factor concerning solubility of phosphonated PSU. Brominated phT8 was prepared with Br2 by a high temperature approach in tetrachloroethane (TCE). Brominated polymers were phosphonated by Ni-catalysis in non-coordinating high temperature solvents, such as diphenylether, benzophenone and diphenylsulfone without notable solvent influence. The lack of solvent - catalyst complexes and high reaction temperatures of 180-200 C led to halogen-free phosphonates with unprecedented high functionalities. Polymer analogous application of P(OSiMe3)3 offered a novel direct access to easily cleavable disilyl ester derivatives. These were obtained from PEEK and PSU in near quantitative yields at NiCl2-loads as

Exciplex dynamics in a conjugated polymer blend of MDMO-PPV and PCNEPV

NARCIS (Netherlands)

Offermans, T.; Hal, van P.A.; Koetse, M.M.; Meskers, S.C.J.; Janssen, R.A.J.; Kafafi, Z.H.

2005-01-01

The photophysical properties of a solution processed blend of two semiconducting polymers with electron donating and electron accepting properties, respectively, as used in polymer photovoltaic devices have been investigated. In the binary mixture of

Non-isothermal crystallization of PET/PLA blends

International Nuclear Information System (INIS)

Chen, Huipeng; Pyda, Marek; Cebe, Peggy

2009-01-01

Binary blends of poly(ethylene terephthalate) with poly(lactic acid), PET/PLA, were studied by differential scanning calorimetry and X-ray scattering. The PET/PLA blends, prepared by solution casting, were found to be miscible in the melt over the entire composition range. Both quenched amorphous and semicrystalline blends exhibit a single, composition dependent glass transition temperature. We report the non-isothermal crystallization of (a) PET, with and without the presence of PLA crystals and (b) PLA, with and without the presence of PET crystals. PET can crystallize in all blends, regardless of whether PLA is amorphous or crystalline, and degree of crystallinity of PET decreases as PLA content increases. In contrast, PLA crystallization is strongly affected by the mobility of the PET fraction. When PET is wholly amorphous, PLA can crystallize even in 70/30 blends, albeit weakly. But when PET is crystalline, PLA cannot crystallize when its own content drops below 0.90. These different behaviors may possibly be related to the tendency of each polymer to form constrained chains, i.e., to form the rigid amorphous fraction, or RAF. PET is capable of forming a large amount of RAF, whereas relatively smaller amount of RAF forms in PLA. Like the crystals, the rigid amorphous fraction of one polymer component may inhibit the growth of crystals of the other blend partner.

Generation of Length Distribution, Length Diagram, Fibrogram, and Statistical Characteristics by Weight of Cotton Blends

Directory of Open Access Journals (Sweden)

B. Azzouz

2007-01-01

Full Text Available The textile fibre mixture as a multicomponent blend of variable fibres imposes regarding the proper method to predict the characteristics of the final blend. The length diagram and the fibrogram of cotton are generated. Then the length distribution, the length diagram, and the fibrogram of a blend of different categories of cotton are determined. The length distributions by weight of five different categories of cotton (Egyptian, USA (Pima, Brazilian, USA (Upland, and Uzbekistani are measured by AFIS. From these distributions, the length distribution, the length diagram, and the fibrogram by weight of four binary blends are expressed. The length parameters of these cotton blends are calculated and their variations are plotted against the mass fraction x of one component in the blend .These calculated parameters are compared to those of real blends. Finally, the selection of the optimal blends using the linear programming method, based on the hypothesis that the cotton blend parameters vary linearly in function of the components rations, is proved insufficient.

Compatibilizing Bulk Polymer Blends by Using Organoclays

Science.gov (United States)

Si, Mayu; Gersappe, Dilip; Zhang, Wenhua; Ade, Harald; Rafailovich, Miriam; Sokolov, Jonathan; Rudomen, Gregory; Schwartz, Bradley; Fisher, Robert

2004-03-01

We investigated the compatiblizing performance of organoclays on melt mixed binary and tertiary polymer blends, such as, PS/PMMA, PC/SAN, PS/PMMA/PVC and PS/PMMA/PE. These polymer blends were characterized by TEM, STXM, DSC and DMA. TEM and STXM photographs show that the addition of organoclays into polymer blends drastically reduces the average domain size of the component phases. And the organoclay goes to the interfacial region between the different polymers and effectively slows down the domain size increasing during high temperature annealing. DMA and DSC results show the effect of organoclays on the mechanical properties and glass transitions temperature, which indicates the compatibilization on the molecular level. The generalized compatibilization induced by the nanoscale fillers for blends can be explained in terms of mean field models where the reduction of interfacial tension induced by in-situ grafting is counterbalanced by the increased bending energy due to the rigidity of the filler. This in turn can be shown to be a function of the degree of exfoliation, aspect ratio, and polymer filler interactions. Supported by NSF funded MRSEC at Stony Brook

Novel poly(vinylidene fluoride-trifluoroethylene)/poly(ethylene oxide) blends for battery separators in lithium-ion applications

International Nuclear Information System (INIS)

Costa, C.M.; Nunes-Pereira, J.; Rodrigues, L.C.; Silva, M.M.; Ribelles, J.L. Gomez; Lanceros-Méndez, S.

2013-01-01

Highlights: ► New P(VDF-TrFE)/PEO polymer blends were prepared for battery separator. ► The porosity and hydrophilicity degree are tailored within this blend. ► Ionic conductivity depends on PEO presence and is stable with temperature. ► High ionic conductivity of 0.25 mS cm −1 for the 60/40 blend. -- Abstract: Polymer blends based on poly(vinylidene fluoride-trifluoroethylene)/poly(ethylene oxide), P(VDF-TrFE)/PEO for Li-ion battery separator applications have been prepared through solvent casting technique. The microstructure, hydrophilicity and electrolyte uptake strongly depend on PEO content within the blend. The best value of ionic conductivity at room temperature was 0.25 mS cm −1 for the 60/40 membrane. The membranes are electrochemically stable

Dynamic filtration and static adsorption of lead ions in aqueous solution by use of blended polysulfone membranes with nano size MCM-41 particles coated by polyaniline.

Science.gov (United States)

Toosi, Mohammad Reza; Emami, Mohammad Reza Sarmasti; Hajian, Sudeh

2018-05-11

MCM-41 mesopore was prepared by hydrothermal method and used for synthesis of polyaniline/MCM-41 nanocomposite via in situ polymerization. The nanocomposite was blended with polysulfone to prepare mixed matrix membrane in different content of nanocomposite by phase inversion method. Structural and surface properties of the samples were characterized by SEM, XRD, FTIR, AFM, TGA, BET, and zeta potential measurements. Effect of the nanocomposite content on the hydrophilicity, porosity, and permeability of the membrane was determined. Membrane performance was evaluated for removal of lead ions in dynamic filtration and static adsorption. The membranes were found as effective adsorptive filters for removal of lead ions via interactions between active sites of nanocomposite in membrane structure and lead ions during filtration. Results of batch experiments proved adsorptive mechanism of membranes for removal of lead ions with the maximum adsorption capacity of 19.6 mg/g.

Neuronal Differentiation Modulated by Polymeric Membrane Properties.

Science.gov (United States)

Morelli, Sabrina; Piscioneri, Antonella; Drioli, Enrico; De Bartolo, Loredana

2017-01-01

In this study, different collagen-blend membranes were successfully constructed by blending collagen with chitosan (CHT) or poly(lactic-co-glycolic acid) (PLGA) to enhance their properties and thus create new biofunctional materials with great potential use for neuronal tissue engineering and regeneration. Collagen blending strongly affected membrane properties in the following ways: (i) it improved the surface hydrophilicity of both pure CHT and PLGA membranes, (ii) it reduced the stiffness of CHT membranes, but (iii) it did not modify the good mechanical properties of PLGA membranes. Then, we investigated the effect of the different collagen concentrations on the neuronal behavior of the membranes developed. Morphological observations, immunocytochemistry, and morphometric measures demonstrated that the membranes developed, especially CHT/Col30, PLGA, and PLGA/Col1, provided suitable microenvironments for neuronal growth owing to their enhanced properties. The most consistent neuronal differentiation was obtained in neurons cultured on PLGA-based membranes, where a well-developed neuronal network was achieved due to their improved mechanical properties. Our findings suggest that tensile strength and elongation at break are key material parameters that have potential influence on both axonal elongation and neuronal structure and organization, which are of fundamental importance for the maintenance of efficient neuronal growth. Hence, our study has provided new insights regarding the effects of membrane mechanical properties on neuronal behavior, and thus it may help to design and improve novel instructive biomaterials for neuronal tissue engineering. © 2017 S. Karger AG, Basel.

Preparation of a Facilitated Transport Membrane Composed of Carboxymethyl Chitosan and Polyethylenimine for CO2/N2 Separation

Directory of Open Access Journals (Sweden)

Jiang-Nan Shen

2013-02-01

Full Text Available The miscibility of carboxymethyl chitosan/polyethylenimine (CMCS/PEI blends was analyzed by FT-IR, TGA and SEM. Defect-free CMCS/PEI blend membranes were prepared with polysulfone (PSf ultrafiltration membranes as support layer for the separation of CO2/N2 mixtures. The results demonstrate that the CMCS/PEI blend is miscible, due to the hydrogen bonding interaction between the two targeted polymers. For the blended membrane without water, the permeability of CO2 gas is 3.6 × 10−7 cm3 cm−2 s−1 cmHg−1 and the corresponding separation factor for CO2 and N2 gas is about 33 at the pressure of 15.2 cmHg. Meanwhile, the blended membrane with water has the better permselectivity. The blended membrane containing water with PEI content of 30 wt% has the permeance of 6.3 × 10−4 cm3 cm−2 s−1 cmHg−1 for CO2 gas and a separation factor of 325 for CO2/N2 mixtures at the same feed pressure. This indicates that the CO2 separation performance of the CMCS/PEI blend membrane is higher than that of other facilitated transport membranes reported for CO2/N2 mixture separation.

Pretreatment and Membrane Hydrophilic Modification to Reduce Membrane Fouling

Directory of Open Access Journals (Sweden)

Huaqiang Chu

2013-09-01

Full Text Available The application of low pressure membranes (microfiltration/ultrafiltration has undergone accelerated development for drinking water production. However, the major obstacle encountered in its popularization is membrane fouling caused by natural organic matter (NOM. This paper firstly summarizes the two factors causing the organic membrane fouling, including molecular weight (MW and hydrophilicity/hydrophobicity of NOM, and then presents a brief introduction of the methods which can prevent membrane fouling such as pretreatment of the feed water (e.g., coagulation, adsorption, and pre-oxidation and membrane hydrophilic modification (e.g., plasma modification, irradiation grafting modification, surface coating modification, blend modification, etc.. Perspectives of further research are also discussed.

Pressure and temperature effects in homopolymer blends and diblock copolymers

DEFF Research Database (Denmark)

Frielinghaus, H.; Schwahn, D.; Mortensen, K.

1997-01-01

Thermal composition fluctuations in a homogeneous binary polymer blend and in a diblock copolymer were measured by small-angle neutron scattering as a function of temperature and pressure. The experimental data were analyzed with theoretical expressions, including the important effect of thermal...... fluctuations. Phase boundaries, the Flory-Huggins interaction parameter and the Ginzburg number were obtained. The packing of the molecules changes with pressure. Therefore, the degree of thermal fluctuation as a function of packing and temperature was studied. While in polymer blends packing leads, in some...... respects, to a universal behaviour, such behaviour is not found in diblock copolymers. It is shown that the Ginzburg number decreases with pressure sensitively in blends, while it is constant in diblock copolymers. The Ginzburg number is an estimation of the transition between the universality classes...

Dual-Functional Ultrafiltration Membrane for Simultaneous Removal of Multiple Pollutants with High Performance.

Science.gov (United States)

Pan, Shunlong; Li, Jiansheng; Noonan, Owen; Fang, Xiaofeng; Wan, Gaojie; Yu, Chengzhong; Wang, Lianjun

2017-05-02

Simultaneous removal of multiple pollutants from aqueous solution with less energy consumption is crucial in water purification. Here, a novel concept of dual-functional ultrafiltration (DFUF) membrane is demonstrated by entrapment of nanostructured adsorbents into the finger-like pores of ultrafiltration (UF) membrane rather than in the membrane matrix in previous reports of blend membranes, resulting in an exceptionally high active content and simultaneous removal of multiple pollutants from water due to the dual functions of rejection and adsorption. As a demonstration, hollow porous Zr(OH) x nanospheres (HPZNs) were immobilized in poly(ether sulfone) (PES) UF membranes through polydopamine coating with a high content of 68.9 wt %. The decontamination capacity of DFUF membranes toward multiple model pollutants (colloidal gold, polyethylene glycol (PEG), Pb(II)) was evaluated against a blend membrane. Compared to the blend membrane, the DFUF membranes showed 2.1-fold increase in the effective treatment volume for the treatment of Pb(II) contaminated water from 100 ppb to below 10 ppb (WHO drinking water standard). Simultaneously, the DFUF membranes effectively removed the colloidal gold and PEG below instrument detection limit, however the blend membrane only achieved 97.6% and 96.8% rejection for colloidal gold and PEG, respectively. Moreover, the DFUF membranes showed negligible leakage of nanoadsorbents during testing; and the membrane can be easily regenerated and reused. This study sheds new light on the design of high performance multifunction membranes for drinking water purification.

Effect of the grinding behaviour of coal blends on coal utilisation for combustion

Energy Technology Data Exchange (ETDEWEB)

Rubiera, F.; Arenillas, A.; Fuente, E.; Pis, J.J. [Inst. Nacional del Carbon, CSIC, Oviedo (Spain); Miles, N. [School of Chemical, Environmental and Mining Engineering, Nottingham Univ. (United Kingdom)

1999-11-01

Grinding of a high volatile bituminous coal was performed in three comminution devices: Raymond Mill (RM), Rolls Crusher (RC) and Ball Mill (BM). The pulverised samples were sieved to obtain four particle size fractions, and temperature-programmed combustion (TPC) was used for the evaluation of their combustion behaviour. In addition, three coals of different hardness and rank were mixed in various proportions in order to compare the combustibility characteristics of the binary coal blends with those of the individual coals. The effect of coal blending on grindability was also studied. It was found that grindability was non-additive especially when coals of very different hardgrove grindability index (HGI) were blended. The combustion studies also suggested that there exists an interaction between individual coals when they are burnt as a blend. (orig.)

Supertoughened renewable PLA reactive multiphase blends system: phase morphology and performance.

Science.gov (United States)

Zhang, Kunyu; Nagarajan, Vidhya; Misra, Manjusri; Mohanty, Amar K

2014-08-13

Multiphase blends of poly(lactic acid) (PLA), ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) terpolymer, and a series of renewable poly(ether-b-amide) elastomeric copolymer (PEBA) were fabricated through reactive melt blending in an effort to improve the toughness of the PLA. Supertoughened PLA blend showing impact strength of ∼500 J/m with partial break impact behavior was achieved at an optimized blending ratio of 70 wt % PLA, 20 wt % EMA-GMA, and 10 wt % PEBA. Miscibility and thermal behavior of the binary blends PLA/PEBA and PLA/EMA-GMA, and the multiphase blends were also investigated through differential scanning calorimetric (DSC) and dynamic mechanical analysis (DMA). Phase morphology and fracture surface morphology of the blends were studied through scanning electron microscopy (SEM) and atomic force microscopy (AFM) to understand the strong corelation between the morphology and its significant effect on imparting tremendous improvement in toughness. A unique "multiple stacked structure" with partial encapsulation of EMA-GMA and PEBA minor phases was observed for the PLA/EMA-GMA/PEBA (70/20/10) revealing the importance of particular blend composition in enhancing the toughness. Toughening mechanism behind the supertoughened PLA blends have been established by studying the impact fractured surface morphology at different zones of fracture. Synergistic effect of good interfacial adhesion and interfacial cavitations followed by massive shear yielding of the matrix was believed to contribute to the enormous toughening effect observed in these multiphase blends.

Enhanced antifouling and antibacterial properties of poly (ether sulfone) membrane modified through blending with sulfonated poly (aryl ether sulfone) and copper nanoparticles

Science.gov (United States)

Zhang, Jingjing; Xu, Ya'nan; Chen, Shouwen; Li, Jiansheng; Han, Weiqing; Sun, Xiuyun; Wu, Dihua; Hu, Zhaoxia; Wang, Lianjun

2018-03-01

A series of novel blend ultrafiltration (UF) membranes have been successfully prepared from commercial poly (ether sulfone), lab-synthesized sulfonated poly (aryl ether sulfone) (SPAES, 1 wt%) and copper nanoparticles (0 ∼ 0.4 wt%) via immersion precipitation phase conversion. The micro-structure and separation performance of the membranes were characterized by field emission scanning electron microscopy (SEM) and cross-flow filtration experiments, respectively. Sodium alginate, bovine serum albumin and humic acid were chosen as model organic foulants to investigate the antifouling properties, while E. coil was used to evaluate the antibacterial property of the fabricated membranes. By the incorporation with SPAES and copper nanoparticles, the hydrophilicity, antifouling and antibacterial properties of the modified UF membranes have been profoundly improved. At a copper nanoparticles content of 0.4 wt%, the PES/SPAES/nCu(0.4) membrane exhibited a high pure water flux of 193.0 kg/m2 h, reaching the smallest contact angle of 52°, highest flux recovery ratio of 79% and largest antibacterial rate of 78.9%. Furthermore, the stability of copper nanoparticles inside the membrane matrix was also considerably enhanced, the copper nanoparticles were less than 0.08 mg/L in the effluent during the whole operation.

Integrating seawater desalination and wastewater reclamation forward osmosis process using thin-film composite mixed matrix membrane with functionalized carbon nanotube blended polyethersulfone support layer.

Science.gov (United States)

Choi, Hyeon-Gyu; Son, Moon; Choi, Heechul

2017-10-01

Thin-film composite mixed matrix membrane (TFC MMM) with functionalized carbon nanotube (fCNT) blended in polyethersulfone (PES) support layer was synthesized via interfacial polymerization and phase inversion. This membrane was firstly tested in lab-scale integrating seawater desalination and wastewater reclamation forward osmosis (FO) process. Water flux of TFC MMM was increased by 72% compared to that of TFC membrane due to enhanced hydrophilicity. Although TFC MMM showed lower water flux than TFC commercial membrane, enhanced reverse salt flux selectivity (RSFS) of TFC MMM was observed compared to TFC membrane (15% higher) and TFC commercial membrane (4% higher), representing membrane permselectivity. Under effluent organic matter (EfOM) fouling test, 16% less normalized flux decline of TFC MMM was observed compared to TFC membrane. There was 8% less decline of TFC MMM compared to TFC commercial membrane due to fCNT effect on repulsive foulant-membrane interaction enhancement, caused by negatively charged membrane surface. After 10 min physical cleaning, TFC MMM displayed higher recovered normalized flux than TFC membrane (6%) and TFC commercial membrane (4%); this was also supported by visualized characterization of fouling layer. This study presents application of TFC MMM to integrated seawater desalination and wastewater reclamation FO process for the first time. It can be concluded that EfOM fouling of TFC MMM was suppressed due to repulsive foulant-membrane interaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tough Blends of Polylactide and Castor Oil

Energy Technology Data Exchange (ETDEWEB)

Robertson, Megan L.; Paxton, Jessica M.; Hillmyer, Marc A. (UMM)

2012-10-10

Poly(l-lactide) (PLLA) is a renewable resource polymer derived from plant sugars with several commercial applications. Broader implementation of the material is limited due to its inherent brittleness. We show that the addition of 5 wt % castor oil to PLLA significantly enhances the overall tensile toughness with minimal reductions in the modulus and no plasticization of the PLLA matrix. In addition, we used poly(ricinoleic acid)-PLLA diblock copolymers, synthesized entirely from renewable resources, as compatibilizers for the PLLA/castor oil blends. Ricinoleic acid, the majority fatty acid comprising castor oil, was polymerized through a lipase-catalyzed condensation reaction. The resulting polymers contained a hydroxyl end-group that was subsequently used to initiate the ring-opening polymerization of L-lactide. The binary PLLA/castor oil blend exhibited a tensile toughness seven times greater than neat PLLA. The addition of block copolymer allowed for control over the morphology of the blends, and even further improvement in the tensile toughness was realized - an order of magnitude larger than that of neat PLLA.

Tough blends of polylactide and castor oil.

Science.gov (United States)

Robertson, Megan L; Paxton, Jessica M; Hillmyer, Marc A

2011-09-01

Poly(l-lactide) (PLLA) is a renewable resource polymer derived from plant sugars with several commercial applications. Broader implementation of the material is limited due to its inherent brittleness. We show that the addition of 5 wt % castor oil to PLLA significantly enhances the overall tensile toughness with minimal reductions in the modulus and no plasticization of the PLLA matrix. In addition, we used poly(ricinoleic acid)-PLLA diblock copolymers, synthesized entirely from renewable resources, as compatibilizers for the PLLA/castor oil blends. Ricinoleic acid, the majority fatty acid comprising castor oil, was polymerized through a lipase-catalyzed condensation reaction. The resulting polymers contained a hydroxyl end-group that was subsequently used to initiate the ring-opening polymerization of l-lactide. The binary PLLA/castor oil blend exhibited a tensile toughness seven times greater than neat PLLA. The addition of block copolymer allowed for control over the morphology of the blends, and even further improvement in the tensile toughness was realized-an order of magnitude larger than that of neat PLLA.

Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

International Nuclear Information System (INIS)

Susanto, H.; Roihatin, A.; Aryanti, N.; Anggoro, D.D.; Ulbricht, M.

2012-01-01

This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 ± 4.2 o to 37.8 ± 4.2 o to 42.5 ± 4.3 o depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65 deg. to 54 deg. for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix. Highlights: ► We compared different methods to prepare low fouling ultrafiltration (UF) membranes. �

Study of the Transformations of Micro/Nano-crystalline Acetaminophen Polymorphs in Drug-Polymer Binary Mixtures.

Science.gov (United States)

Maniruzzaman, Mohammed; Lam, Matthew; Molina, Carlos; Nokhodchi, Ali

2017-07-01

This study elucidates the physical properties of sono-crystallised micro/nano-sized acetaminophen/paracetamol (PMOL) and monitors its possible transformation from polymorphic form I (monoclinic) to form II (orthorhombic). Hydrophilic Plasdone® S630 copovidone (S630), N-vinyl-2-pyrrolidone and vinyl acetate copolymer, and methacrylate-based cationic copolymer, Eudragit® EPO (EPO), were used as polymeric carriers to prepare drug/polymer binary mixtures. Commercially available PMOL was crystallised under ultra sound sonication to produce micro/nano-sized (0.2-10 microns) crystals in monoclinic form. Homogeneous binary blends of drug-polymer mixtures at various drug concentrations were obtained via a thorough mixing. The analysis conducted via the single X-ray crystallography determined the detailed structure of the crystallised PMOL in its monoclinic form. The solid state and the morphology analyses of the PMOL in the binary blends evaluated via differential scanning calorimetry (DSC), modulated temperature DSC (MTDSC), scanning electron microscopy (SEM) and hot stage microscopy (HSM) revealed the crystalline existence of the drug within the amorphous polymeric matrices. The application of temperature controlled X-ray diffraction (VTXRPD) to study the polymorphism of PMOL showed that the most stable form I (monoclinic) was altered to its less stable form II (orthorhombic) at high temperature (>112°C) in the binary blends regardless of the drug amount. Thus, VTXRD was used as a useful tool to monitor polymorphic transformations of crystalline drug (e.g. PMOL) to assess their thermal stability in terms of pharmaceutical product development and research.

Highly antifouling and antibacterial performance of poly (vinylidene fluoride) ultrafiltration membranes blending with copper oxide and graphene oxide nanofillers for effective wastewater treatment.

Science.gov (United States)

Zhao, Chuanqi; Lv, Jinling; Xu, Xiaochen; Zhang, Guoquan; Yang, Yuesuo; Yang, Fenglin

2017-11-01

Innovation and effective wastewater treatment technology is still in great demand given the emerging contaminants frequently spotted from the aqueous environment. By blending with poly (vinylidene fluoride) (PVDF), the strong hydrophilic graphene oxide (GO) and antibacterial copper oxide (Cu x O) were used as nanofillers to develop the novel, highly antifouling composite membranes via phase inversion process in our latest work. The existence and dispersion of GO and Cu x O posed a significant role on morphologies, structures, surface composition and hydrophilicity of the developed composite membranes, confirmed by SEM, TEM, FTIR and XPS in depth characterization. The SEM images showed that the modified membranes presented a lower resistant structure with developed finger-like macrovoids and thin-walled even interconnected sponge-like pores after adding nanofillers, much encouraging membrane permeation. The XPS results revealed that Cu x O contained Cu 2 O and CuO in the developed membrane and the Cu 2 O nanoparticles were dominant accounting for about 79.3%; thus the modified membrane specifically exhibited an efficient antibacterial capacity. Due to the hydrophilic and bactericidal membrane surface, the composite membranes demonstrated an excellent antifouling performance, including higher flux recovery rate, more resistant against accumulated contaminants and lower filtration resistance, especially lower irreversible resistance. The antifouling property, especially anti-irreversible fouling, was significantly improved, showing a significant engineering potential. Copyright © 2017 Elsevier Inc. All rights reserved.

Highly toughened polypropylene/ethylene–propylene-diene monomer/zinc dimethacrylate ternary blends prepared via peroxide-induced dynamic vulcanization

Energy Technology Data Exchange (ETDEWEB)

Chen, Yukun, E-mail: cyk@scut.edu.cn [The Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Xu, Chuanhui [College of Material Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Cao, Liming [The Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Cao, Xiaodong [College of Material Science and Engineering, South China University of Technology, Guangzhou 510640 (China)

2013-02-15

Polypropylene (PP)/ethylene–propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blends with remarkable toughness and extensibility were successfully prepared via peroxide dynamical vulcanization. A unique structure with the EPDM particles surrounded by a transition zone containing numerous polymerized ZDMA (PZDMA) nano-particles was observed for the first time by using transmission electron microscopy (TEM) examination, which contributed to the dramatically increase of Izod impact strength. Dynamic mechanical analysis (DMA) confirmed that the possible PZDMA graft products resulted from peroxide dynamical vulcanization improved the compatibility between EPDM and PP phases. The specific morphology of the PP/EPDM/ZDMA blends indicated that ZDMA can lead to size reduction and good distribution uniformity of the crosslinked rubber particles and the increase of adhesion between PP matrix and EPDM phases during deformation. The synergic effect of the increase in the effective volume of the EPDM phase, the improved compatibility and adhesion between EPDM and PP phases and the deformation of those fine rubber particles is believed to result in the remarkable high toughness and extensibility of the PP/EPDM/ZDMA blends. Particularly for the PP/EPDM ratio of 70/30, the PP/EPDM/ZDMA (70/30/9, w/w/w) ternary blends with the Izod impact strength nearly 2 times higher than PP/EPDM (70/30, w/w) binary blends and 15–20 times higher than PP are achieved; besides, the elongation at break of PP/EPDM/ZDMA ternary blends is 4–5 times higher than that of PP/EPDM binary blends. - Highlights: ► ZDMA largely toughen peroxide dynamically vulcanized PP/EPDM blend. ► PZDMA graft products improved the compatibility and adhesion between EPDM and PP. ► Size reduction and good distribution uniformity of crosslinked rubber particles.

Highly toughened polypropylene/ethylene–propylene-diene monomer/zinc dimethacrylate ternary blends prepared via peroxide-induced dynamic vulcanization

International Nuclear Information System (INIS)

Chen, Yukun; Xu, Chuanhui; Cao, Liming; Cao, Xiaodong

2013-01-01

Polypropylene (PP)/ethylene–propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blends with remarkable toughness and extensibility were successfully prepared via peroxide dynamical vulcanization. A unique structure with the EPDM particles surrounded by a transition zone containing numerous polymerized ZDMA (PZDMA) nano-particles was observed for the first time by using transmission electron microscopy (TEM) examination, which contributed to the dramatically increase of Izod impact strength. Dynamic mechanical analysis (DMA) confirmed that the possible PZDMA graft products resulted from peroxide dynamical vulcanization improved the compatibility between EPDM and PP phases. The specific morphology of the PP/EPDM/ZDMA blends indicated that ZDMA can lead to size reduction and good distribution uniformity of the crosslinked rubber particles and the increase of adhesion between PP matrix and EPDM phases during deformation. The synergic effect of the increase in the effective volume of the EPDM phase, the improved compatibility and adhesion between EPDM and PP phases and the deformation of those fine rubber particles is believed to result in the remarkable high toughness and extensibility of the PP/EPDM/ZDMA blends. Particularly for the PP/EPDM ratio of 70/30, the PP/EPDM/ZDMA (70/30/9, w/w/w) ternary blends with the Izod impact strength nearly 2 times higher than PP/EPDM (70/30, w/w) binary blends and 15–20 times higher than PP are achieved; besides, the elongation at break of PP/EPDM/ZDMA ternary blends is 4–5 times higher than that of PP/EPDM binary blends. - Highlights: ► ZDMA largely toughen peroxide dynamically vulcanized PP/EPDM blend. ► PZDMA graft products improved the compatibility and adhesion between EPDM and PP. ► Size reduction and good distribution uniformity of crosslinked rubber particles

Electrospun nanofibrous SF/P(LLA-CL) membrane: a potential substratum for endothelial keratoplasty.

Science.gov (United States)

Chen, Junzhao; Yan, Chenxi; Zhu, Mengyu; Yao, Qinke; Shao, Chunyi; Lu, Wenjuan; Wang, Jing; Mo, Xiumei; Gu, Ping; Fu, Yao; Fan, Xianqun

2015-01-01

Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF) has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-ε-caprolactone) (P(LLA-CL)) has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL) can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty. Five scaffolds containing different SF:P(LLA-CL) blended ratios (100:0, 75:25, 50:50, 25:75, 0:100) were manufactured. A human corneal endothelial (B4G12) cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test), cell proliferation (Ki-67, BrdU staining), and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction. Different blended ratios of scaffolds had different light transmittance properties. The 25:75 blended ratio membrane had the best transmittance among these scaffolds. All electrospun nanofibrous membranes showed improved speed of cell adherence when compared with the control group, especially when the P(LLA-CL) ratio increased. The 25:75 blended ratio membranes also had the highest cell proliferation. B4G12 cells could form a monolayer on all scaffolds, and most functional genes were also stably expressed on all scaffolds. Only two genes

Component dynamics in polymer blends a combined QENS and dielectric spectroscopy investigation

CERN Document Server

Hofmann, S; Arbe, A; Colmenero, J; Faragó, B

2002-01-01

The individual dynamics of the two constituents of a binary polymer blend was studied by means of quasielastic neutron scattering and dielectric spectroscopy (DS). The combination of neutron spin-echo and backscattering techniques allowed us to cover the complete crossover from entropy-driven chain dynamics on mesoscopic scales to the alpha relaxation on local length scales. The observed blending effects on the respective relaxation times suggest a purely dynamic origin of the dynamic heterogeneity in polymer blends at temperatures well above the glass-transition temperature without the need to assume local phase separation. In contrast, the results from DS experiments towards much lower temperatures indicate systematic deviations of the segmental dynamics in the blend from its mean-field-like behavior at high temperatures. This additionally increases the dynamic heterogeneity in the segmental dynamics of the two components in the mixture. In the case of the chain dynamics, no similar effect could be observed...

Miscibility Studies on Polymer Blends Modified with Phytochemicals

Science.gov (United States)

Chandrasekaran, Neelakandan; Kyu, Thein

2009-03-01

The miscibility studies related to an amorphous poly(amide)/poly(vinyl pyrrolidone) [PA/PVP] blend with a crystalline phytochemical called ``Mangiferin'' is presented. Phytochemicals are plant derived chemicals which intrinsically possess multiple salubrious properties that are associated with prevention of diseases such as cancer, diabetes, cardiovascular disease, and hypertension. Incorporation of phytochemicals into polymers has shown to have very promising applications in wound healing, drug delivery, etc. The morphology of these materials is crucial to applications like hemodialysis, which is governed by thermodynamics and kinetics of the phase separation process. Hence, miscibility studies of PA/PVP blends with and without mangiferin have been carried out using dimethyl sulfoxide as a common solvent. Differential scanning calorimetry studies revealed that the binary PA/PVP blends were completely miscible at all compositions. However, the addition of mangiferin has led to liquid-liquid phase separation and liquid-solid phase transition in a composition dependent manner. Fourier transformed infrared spectroscopy was undertaken to determine specific interaction between the polymer constituents and the role of possible hydrogen bonding among three constituents will be discussed.

Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

Energy Technology Data Exchange (ETDEWEB)

Susanto, H., E-mail: heru.susanto@undip.ac.id [Department of Chemical Engineering, Universitas Diponegoro, Jl. Prof. Sudarto-Tembalang, Semarang (Indonesia); Roihatin, A.; Aryanti, N.; Anggoro, D.D. [Department of Chemical Engineering, Universitas Diponegoro, Jl. Prof. Sudarto-Tembalang, Semarang (Indonesia); Ulbricht, M. [Lehrstuhl fuer Technische Chemie, Universitaet Duisburg-Essen, Germany, Universitaetstr. 5, Essen (Germany)

2012-10-01

This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 {+-} 4.2{sup o} to 37.8 {+-} 4.2{sup o} to 42.5 {+-} 4.3{sup o} depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65 deg. to 54 deg. for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix. Highlights: Black-Right-Pointing-Pointer We compared different methods to prepare low

Film-thickness dependence of structure formation in ultra-thin polymer blend films

CERN Document Server

Gutmann, J S; Stamm, M

2002-01-01

We investigated the film-thickness dependence of structure formation in ultra-thin polymer blend films prepared from solution. As a model system we used binary blends of statistical poly(styrene-co-p-bromostyrene) copolymers of different degrees of bromination. Ultra-thin-film samples differing in miscibility and film thickness were prepared via spin coating of common toluene solutions onto silicon (100) substrates. The resulting morphologies were investigated with scanning force microscopy, reflectometry and grazing-incidence scattering techniques using both X-rays and neutrons in order to obtain a picture of the sample structure at and below the sample surface. (orig.)

Separation of Binary Mixtures of Propylene and Propane by Facilitated Transport through Silver Incorporated Poly(Ether-Block-Amide Membranes

Directory of Open Access Journals (Sweden)

Surya Murali R.

2015-02-01

Full Text Available The separation of propylene and propane is a challenging task in petroleum refineries due to the similar molecular sizes and physical properties of two gases. Composite Poly(ether-block-amide (Pebax-1657 membranes incorporated with silver tetra fluoroborate (AgBF4 in concentrations of 0-50% of the polymer weight were prepared by solution casting and solvent evaporation technique. The membranes were characterized by Scanning Electron Microscopy (SEM, Fourier Transform InfraRed (FTIR and wide-angle X-ray Diffraction (XRD to study surface and cross-sectional morphologies, effect of incorporation on intermolecular interactions and degree of crystallinity, respectively. Experimental data was measured with an indigenously built high-pressure gas separation manifold having an effective membrane area of 42 cm2. Permeability and selectivity of membranes were determined for three different binary mixtures of propylene-propane at pressures varying in the range 2-6 bar. Selectivity of C3H6/C3H8 enhanced from 2.92 to 17.22 and 2.11 to 20.38 for 50/50 and 66/34 C3H6+C3H8 feed mixtures, respectively, with increasing loading of AgBF4. Pebax membranes incorporated with AgBF4 exhibit strong potential for the separation of C3H6/C3H8 mixtures in petroleum refineries.

Oral sustained release tablets of zidovudine using binary blends of natural and synthetic polymers.

Science.gov (United States)

Emeje, Martins; Olaleye, Olajide; Isimi, Christiana; Fortunak, Joseph; Byrn, Stephen; Kunle, Olobayo; Ofoefule, Sabinus

2010-01-01

Oral sustained release matrix tablets of zidovudine (ZDV) were prepared using different types, proportions and blends of carbopol 71G (C71) and a plant gum obtained from Abelmoschus esculentus (AEG). The effect of various formulation factors like polymer proportion, polymer type and pH of the dissolution medium on the in vitro release of the drug was studied, using the half change technique, in 900 ml of dissolution medium, at 100 rpm. Release kinetics were analyzed using Zero-order, Higuchi's square-root and Ritger-Peppas' empirical equations. In vitro release performance as revealed by the time taken for 70% of the drug to be released (t70%), showed that the release rate decreased with increase in polymer proportion. Matrix tablets containing 10 and 20% AEG were found to exhibit immediate-release characteristics. Matrix tablets containing 30% AEG showed t70% value of 204 min and extended the release up to 5 h, while matrix tablets containing 30% carbopol showed t70% value of 234 min and extended the release up to 6 h. Three blends of AEG and C71 at the ratio of 1:2, 2:1 and 1:3 showed t70% values of 132, 312 and 102 min respectively and extended the release up to 8 h. Mathematical analysis of the release kinetics indicated that the nature of drug release from the matrix tablets followed Fickian and anomalous release. Drug release from matrix tablets of zidovudine containing blends of AEG and C71 demonstrates the advantage of blending a natural and synthetic polymer over single polymer use.

Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

DEFF Research Database (Denmark)

Aili, David; Javakhishvili, Irakli; Han, Junyoung

2016-01-01

A new amino-functional polybenzimidazole copolymer is synthesized by homogeneous solution condensation polymerization from a novel monomer, N,N′-bis (2,4-diaminophenyl)-1,3-diaminopropane. The copolymer readily dissolves in organic solvents and shows good film forming characteristics. To balance...... the phosphoric acid uptake and to obtain mechanically robust membranes, the amino-functional polybenzimidazole derivative is blended with high molecular weight poly [2,2′-(m-phenylene)-5,5′-bisbenzimidazole] at different ratios. Due to the high acid uptake, the homogenous blend membranes show enhanced proton...

Partially fluorinated aarylene polyethers and their ternary blends with PBI and H3PO4

DEFF Research Database (Denmark)

Li, Qingfeng; Jensen, Jens Oluf; Pan, Chao

2008-01-01

Ternary blend membranes based on sulphonated partially fluorinated arylene polyether, polybenzimidazole (PBI) and phosphoric acid were prepared and characterised as electrolyte for high temperature proton exchange membrane fuel cells. Partially fluorinated arylene polyether was first prepared from...

Use of Novel Reinforced Cation Exchange Membranes for Microbial Fuel Cells

International Nuclear Information System (INIS)

Kamaraj, Sathish-Kumar; Romano, Sergio Mollá; Moreno, Vicente Compañ; Poggi-Varaldo, H.M.; Solorza-Feria, O.

2015-01-01

This work has been focused on the synthesis and characterization of different blended membranes SPEEK-35PVA (Water), SPEEK-35PVA (DMAc) prepared by casting and nanofiber-reinforced proton exchange membranes Nafion-PVA-15, Nafion-PVA-23 and SPEEK/PVA-PVB. The two first reinforced membranes were made up of Nafion® polymer deposited between polyvinyl alcohol (PVA) nanofibers. The last composite membrane is considered because the PVA is a hydrophilic polymer which forms homogeneous blends with SPEEK suitable to obtain high proton conductivity, while the hydrophobic PVB can produce blends in a phase separation morphology in which very low water uptake can be found. The synthesized membranes showed an outstanding stability, high proton conductivity, and enhanced mechanical and barrier properties. The membranes were characterized in single chamber microbial fuel cells (SCMFCs) using electrochemically enriched high sodic saline hybrid H-inocula (Geobacter metallireducen, Desulfurivibrio alkaliphilus, and Marinobacter adhaerens) as biocatalyst. The best performance was obtained with Nafion-PVA-15 membrane, which achieved a maximum power density of 1053 mW/m 3 at a cell voltage of 340 mV and displayed the lowest total internal resistance (Rint ≈ 522 Ω). This result is in agreement with the low oxygen permeability and the moderate conductivity found in this kind of membranes. These results are encouraging towards obtaining high concentrated sodic saline model wastewater exploiting MFCs

Fullerene alloy formation and the benefits for efficient printing of ternary blend organic solar cells

DEFF Research Database (Denmark)

Angmo, Dechan; Bjerring, Morten; Nielsen, Niels Chr.

2015-01-01

behaving as pseudo-binary mixtures due to alloying of the fullerene components. This finding has vast implications for the understanding of polymer–fullerene mixtures and quite certainly also their application in organic solar cells where performance hinges critically on the blend behaviour which is also...

Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

H Ma; B Hsiao; B Chu

2011-12-31

The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

Development and characterisation of electrically conductive polymeric-based blends for proton exchange membrane fuel cell bipolar plates

Energy Technology Data Exchange (ETDEWEB)

Bouatia, S.; Mighri, F. [Center for Applied Research on Polymers and Composites, CREPEC, Department of Chemical Engineering, Laval University, Quebec (Canada); Bousmina, M. [Center for Applied Research on Polymers and Composites, CREPEC, Department of Chemical Engineering, Laval University, Quebec (Canada); Canada Research Chair on Polymer Physics and Nanomaterials, Department of Chemical Engineering, Laval University, Quebec (Canada); Hassan II Academy of Science and Technology, Rabat (Morocco)

2008-04-15

The main objective of this work was to develop films with controlled dimensions for proton exchange membrane fuel cell (PEMFC) bipolar plates (BPPs) using the twin-screw extrusion process. These films consisted of a low-viscosity polyethylene terephthalate (PET) in which a mixture of high specific surface area carbon black (CB) and synthetic flake graphite (GR) were dispersed. A third conductive additive, consisting of silver-coated glass particles (SCG) or multi-walled carbon nanotubes (MWCNT), was also added at a low concentration (5 wt.-%) in order to study its synergistic effect on the PET-based blend electrical conductivity. As the developed blends had to meet properties suitable for PEMFC bipolar plate applications, they were characterised for their electrical through-plane resistivity, mechanical properties and oxygen permeability. Through-plane electrical resistivity of about 0.3 {omega}.cm and oxygen permeation rate of 3.5 x 10{sup -8} cc cm{sup -2} s{sup -1} were obtained for only 30 wt.-% of a 60:40 mixture of CB/GR conductive additives. Although the substitution of 5 wt.-% of CB/GR by the same amount of MWCNT had no significant effect on BPPs' electrical resistivity, it helped to improve their mechanical properties and especially their oxygen permeation, which was decreased from 3.5 x 10{sup -8} cc cm{sup -2} s{sup -1} to around 0.6 x 10{sup -8} cc cm{sup -2}s{sup -1}. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Dynamics and order-disorder transitions in bidisperse diblock copolymer blends

International Nuclear Information System (INIS)

Wang Yueqiang; Li Xuan; Tang Ping; Yang Yuliang

2011-01-01

We employ the dynamic extension of self-consistent field theory (DSCFT) to study dynamics and order-disorder transitions (ODT) in AB diblock copolymer binary mixtures of two different monodisperse chain lengths by imitating the dynamic storage modulus G' corresponding to any given morphology in the oscillatory shear measurements. The different polydispersity index (PDI) is introduced by binary blending AB diblock copolymers with variations in chain lengths and chain number fractions. The simulation results show that the increase of polydispersity in the minority or symmetric block introduces a decrease in the segregation strength at the ODT, (χN) ODT , whereas the increase of polydispersity in the majority block results in a decrease, then increase and final decrease again in (χN) ODT . To the best of our knowledge, our DSCFT simulations, for the first time, predict an increase in (χN) ODT with the PDI in the majority block, which produces the experimental results. The simulations by previous SCFT, which generally speaking, is capable of describing equilibrium morphologies, however, contradict the experimental data. The polydispersity acquired by properly tuning the chain lengths and number fractions of binary diblock copolymer blends should be a convenient and efficient way to control the microphase separation strength at the ODT. -- Research highlights: → Order-disorder transition in AB diblock copolymer mixtures is investigated using DSCFT. → Microphase separation strength at the ODT increases with PDI in the majority block. → Microphase separation strength at the ODT decreases with PDI in the minority block. → Introduction of polydispersity is efficient to control microphase separation strength at the ODT.

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

Science.gov (United States)

Hirota, Yuichiro; Maeda, Yohei; Yamamoto, Yusuke; Miyamoto, Manabu; Nishiyama, Norikazu

2017-08-03

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H₂/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H₂ (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

THE EFFECT OF TYPE ZEOLITE ON THE GAS TRANSPORT PROPERTIES OF POLYIMIDE-BASED MIXED MATRIX MEMBRANES

Directory of Open Access Journals (Sweden)

Tutuk Djoko Kusworo

2012-01-01

Full Text Available The permeation rates of O2, N2, CO2 and CH4 has been studied for polyimide-polyethersulfone (PI/PES blends-zeolite mixed matrix membranes synthesized in our laboratory. The study investigated the effect of zeolite loading and different zeolite type on the gas separation performance of these mixed matrix membranes. Frequency shifts and absorption intensity changes in the FTIR spectra of the PI/PES blends as compared with those of the pure polymers indicate that there is a mixing of polymer blends at the molecular level. Differential scanning calorimetry measurements of pure and PI/PES blends membranes have showed one unique glass transition temperature that supports the miscible character of the PI/PES mixture. The PI/PES-zeolite 4A mixed matrix membrane with 25 wt % zeolite loading produced the highest O2/N2 and CO2/CH4 selectivity of around 7.45 and 46.05, respectively.

The durability of concrete containing a high-level of fly ash or a ternary blend of supplementary cementing materials

Science.gov (United States)

Gilbert, Christine M.

The research for this study was conducted in two distinct phases as follows: Phase 1: The objective was to determine the effect of fly ash on the carbonation of concrete. The specimens made for this phase of the study were larger in size than those normally used in carbonation studies and were are meant to more accurately reflect real field conditions. The results from early age carbonation testing indicate that the larger size specimens do not have a measured depth of carbonation as great as that of the smaller specimens typically used in carbonation studies at the same age and under the same conditions. Phase 2: The objective was to evaluate the performance of ternary concrete mixes containing a ternary cement blend consisting of Portland cement, slag and Type C fly ash. It was found that concrete mixtures containing the fly ash with the lower calcium (CaO) content (in binary or ternary blends) provided superior durability performance and resistance to ASR compared to that of the fly ash with the higher CaO content. Ternary blends (regardless of the CaO content of the fly ash) provided better overall durability performance than binary blends of cementing materials or the control.

Hydrophilicity improvement in polyphenylsulfone nanofibrous filtration membranes through addition of polyethylene glycol

Energy Technology Data Exchange (ETDEWEB)

Kiani, Shirin [Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Membrane Processes and Membrane Research Center, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Mousavi, Seyed Mahmoud, E-mail: mmousavi@um.ac.ir [Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Shahtahmassebi, Nasser [Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Nanoresearch Center, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Saljoughi, Ehsan [Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

2015-12-30

Highlights: • Novel hydrophilic polyphenylsulfone electrospun nanofibrous membrane was prepared. • Blending the PPSU solution with 10 wt.% PEG 400 led to the optimum results. • Water contact angle of the optimum membrane was determined as 8.9°. • Remarkable increase in pure water flux and flux recovery was achieved. • Rejection values of the wastewater pollution indices remained almost unchanged. - Abstract: Novel hydrophilic polyphenylsulfone (PPSU) nanofibrous membrane was prepared by electrospinning of the PPSU solution blended with polyethylene glycol 400 (PEG 400). The influence of the PEG concentration on the membrane characteristics was studied using scanning electron microscopy (SEM), water contact angle measurement, and tensile test. Filtration performance of the membranes was investigated by measurement of pure water flux (PWF) and determination of the rejection values of the pollution indices during treatment of canned beans production wastewater. According to the results, blending the PPSU solution with 10 wt.% PEG 400 resulted in formation of a nanofibrous membrane with high porosity and increased mechanical strength which exhibited a low water contact angle of 8.9° and high water flux of 7920 L/m{sup 2}h. Flux recovery of the mentioned membrane which was assessed by filtration of a solution containing bovine serum albumin (BSA) was 83% indicating a noticeable antifouling property.

How Chain Intermixing Dictates the Polymorphism of PVDF in Poly(vinylidene fluoride/Polymethylmethacrylate Binary System during Recrystallization: A Comparative Study on Core–Shell Particles and Latex Blend

Directory of Open Access Journals (Sweden)

Yue Li

2017-09-01

Full Text Available In the past few decades, Poly(vinylidene fluoride/Polymethylmethacrylate (PVDF/PMMA binary blend has attracted substantial attention in the scientific community due to possible intriguing mechanical, optical and ferroelectric properties that are closely related to its multiple crystal structures/phases. However, the effect of PMMA phase on the polymorphism of PVDF, especially the relationship between miscibility and polymorphism, remains an open question and is not yet fully understood. In this work, three series of particle blends with varied levels of miscibility between PVDF and PMMA were prepared via seeded emulsion polymerization: PVDF–PMMA core–shell particle (PVDF@PMMA with high miscibility; PVDF/PMMA latex blend with modest miscibility; and PVDF@c–PMMA (crosslinked PMMA core–shell particle with negligible miscibility. The difference in miscibility, and the corresponding morphology and polymorphism were systematically studied to correlate the PMMA/PVDF miscibility with PVDF polymorphism. It is of interest to observe that the formation of polar β/γ phase during melt crystallization could be governed in two ways: dipole–dipole interaction and fast crystallization. For PVDF@PMMA and PVDF/PMMA systems, in which fast crystallization was unlikely triggered, higher content of β/γ phase, and intense suppression of crystallization temperature and capacity were observed in PVDF@PMMA, because high miscibility favored a higher intensity of overall dipole–dipole interaction and a longer interaction time. For PVDF@c–PMMA system, after a complete coverage of PVDF seeds by PMMA shells, nearly pure β/γ phase was obtained owing to the fast homogeneous nucleation. This is the first report that high miscibility between PVDF and PMMA could favor the formation of β/γ phase.

Ultraporous interweaving electrospun microfibers from PCL-PEO binary blends and their cellular response

DEFF Research Database (Denmark)

Chen, Menglin; Li, Yanfang; Besenbacher, Flemming

2015-01-01

from a blend of polycaprolactone (PCL) and polyethylene oxide (PEO) in a DCM-DMF mixed solution when the ratio between each component reached a threshold and when the electrospinning parameters were delicately controlled. We further investigated their influence on cell infiltration and colonization...

Exhaust gas emissions and mutagenic effects of modern diesel fuels, GTL, biodiesel and biodiesel blends

Energy Technology Data Exchange (ETDEWEB)

Munack, Axel; Ruschel, Yvonne; Schroeder, Olaf [Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig (Germany)], E-mail: axel.munack@vti.bund.de; Krahl, Juergen [Coburg Univ. of Applied Sciences (Germany); Buenger, Juergen [University of Bochum (Germany)

2008-07-01

Biodiesel can be used alone (B100) or blended with petroleum diesel in any proportion. The most popular biodiesel blend in the U.S.A. is B20 (20% biodiesel, 80% diesel fuel), which can be used for Energy Policy Act of 1992 (EPAct) compliance. In the European Union, the use of biofuel blends is recommended and was introduced by federal regulations in several countries. In Germany, biodiesel is currently blended as B5 (5% biodiesel) to common diesel fuel. In 2008, B7 plus three percent hydrotreated vegetable oil (HVO) as well is intended to become mandatory in Germany. To investigate the influence of blends on the emissions and possible health effects, we performed a series of studies with several engines (Euro 0, III and IV) measuring regulated and non-regulated exhaust compounds and determining their mutagenic effects. Emissions of blends showed an approximate linear dependence on the blend composition, in particular when regulated emissions are considered. However, a negative effect of blends was observed with respect to mutagenicity of the exhaust gas emissions. In detail, a maximum of the mutagenic potency was found in the range of B20. From this point of view, B20 must be considered as a critical blend, in case diesel fuel and biodiesel are used as binary mixtures. (author)

Degradation behavior of polymer blend of isotactic polypropylenes with and without unsaturated chain end group

International Nuclear Information System (INIS)

Nakatani, Hisayuki; Kurniawan, Dodik; Taniike, Toshiaki; Terano, Minoru

2008-01-01

In this work, the relationship between the unsaturated chain end group content and the thermal oxidative degradation rate was systematically studied with binary polymer blends of isotactic polypropylene (iPP) with and without the unsaturated chain end group. The iPPs with and without the unsaturated chain end group were synthesized by a metallocene catalyst in the absence of hydrogen and by a Ziegler catalyst in the presence of one, respectively. The thermal oxidative degradation rate of the binary iPP blends was estimated from the molecular weight and the apparent activation energy (ΔE), which were obtained through size exclusion chromatography (SEC) and thermogravimetric analysis (TGA) measurements, respectively. These values exhibited a negative correlation against the mole content of the unsaturated chain end group. The thermal oxidative degradation rate apparently depends on the content of the unsaturated chain end group. This tendency suggests that the unsaturated chain end acts as a radical initiator of the iPP degradation reaction.

Effect of Gamma Irradiation on Blends Based on Thermoset or Thermoplast Polymers for Using in Some Useful Applications

International Nuclear Information System (INIS)

EMAN MOHAMED SHEHATA, E.M.

2013-01-01

Modification of polymers via blending and gamma irradiation crosslinking opens the door for solving many industrial problems and broad the application and markets for the products of modified materials. From this point of view, the present work is divided into two main parts. The first part is dealing with the preparation and characterization of alkaline polymer electrolyte membrane based on polyethylene oxide and polyvinylpyrrolidone. The alkaline polymer electrolyte membranes were prepared by two different techniques: immersing the irradiated prepared membranes in different concentration of KOH solutions, and addition of various amounts of KOH to (PEO/PVP) mixture solution during the preparation step. Exposing the prepared membranes to different gamma irradiation doses causes an improvement in the membranes properties such as water solubility and thermal properties. The structure and morphology of the prepared polymer membranes were studied by FTIR spectroscopy and scanning electron microscope. Furthermore, the ionic conductivity of alkaline (PEO/PVP) electrolyte membranes was calculated from Ac impedance spectra. The results obtained showed that the membranes prepared by immersion technique have better properties than the membranes prepared by addition technique. Concerning the second part, urea formaldehyde (UF) as a thermoset amino resin, was modified by exposing to different gamma irradiation doses and blending with various amounts of vinyl acetate versatic ester latex (VAcVe). Gamma irradiation induced the crosslinking of pure UF and (UF/VAcVe) blends. The change in the structure of pure UF and (UF/VAcVe) blends before and after irradiation was investigated by FTIR spectroscopy. Moreover, physical properties such as insoluble fraction percent, water absorption behavior, and effect of dilute acid and alkali were studied. Thermal and mechanical properties were investigated in terms of thermogravimetric analysis and compacting strength measurement. The results

Effect of Evaporation Time on Separation Performance of Polysulfone/Cellulose Acetate (PSF/CA) Membrane

Science.gov (United States)

Syahbanu, Intan; Piluharto, Bambang; Khairi, Syahrul; Sudarko

2018-01-01

Polysulfone and cellulose acetate are common material in separation. In this research, polysulfone/cellulose actetate (PSF/CA) blend membrane was prepared. The aim of this research was to study effect of evaporation time in casting of PSF/CA membrane and its performance in filtration. CA was obtained by acetylation process of bacterial cellulose (BC) from fermentation of coconut water. Fourier Transform Infra Red (FTIR) Spectroscopy was used to examine functional groups of BC, CA and commercial cellulose acetate. Subtitution of acetyl groups determined by titration method. Blend membranes were prepared through phase inversion technique in which composition of PSF/PEG/CA/NMP(%w) was 15/5/5/75. Polyethyleneglycol (PEG) and N-methyl-2-pyrrolidone (NMP) were act as pore forming agent and solvent, respectively. Variation of evaporation times were used as parameter to examine water uptake, flux, and morphology of PSF/CA blend membranes. FTIR spectra of CA show characteristic peak of acetyl group at 1220 cm-1 indicated that BC was acetylated succesfully. Degree of subtitution of BCA was found at 2.62. Highest water flux was performed at 2 bar obtained at 106.31 L.m-2.h-1 at 0 minute variation, and decrease as increasing evaporation time. Morphology of PSF/BCA blend membranes were investigated by Scanning Electron Microscopy (SEM) showed that porous asymetric membrane were formed.

Chain confinement, phase transitions, and lamellar structure in semicrystalline polymers, polymer blends and polymer nanocomposites

Science.gov (United States)

Chen, Huipeng

Recent studies suggest that there are three phase fractions in semicrystalline polymers, the crystalline, the mobile amorphous and the rigid amorphous phases. Due to the distinct properties of the rigid amorphous fraction, RAF, it has been investigated for more than twenty years. In this thesis, a general method using quasi-isothermal temperature-modulated differential scaning calorimetry, DSC, is provided for the first time to obtain the temperature dependent RAF and the other two fractions, crystalline fraction and mobile amorphous fraction, MAF. For poly(ethylene terephthalate), PET, our results show RAF was vitrified during quasi-isothermal cooling after crystallization had been completed and became totally devitrified during quasi-isothermal heating before the start of melting. Several years after people initially discovered the existence of RAF, another issue arose relating to the physical location of RAF and mobile amorphous fraction, MAF, within a lamellar stack model. Two very different models to describe the location of RAF were proposed. In the Heterogeneous Stack Model, HET, RAF is located outside the lamellar stacks. In the Homogeneous Stack Model, HSM, RAF was located inside the lamellar stacks. To determine the lamellar structure of semicrystalline polymers comprising three phase, a general method is given in this thesis by using a combination of the DSC and small angle X-ray scattering, SAXS techniques. It has been applied to Nylon 6, isotactic polystyrene, iPS, and PET. It was found for all of these materials, the HSM model is correct to describe the lamellar structure. In addition to the determination of lamellar structures, this method can also provide the exact fraction of MAF inside and outside lamellar stacks for binary polymer blends. For binary polymer blends, MAF, normally is located partially inside and partially outside the lamellar stacks. However, the quantification of the MAF inside and outside the lamellar stacks has now been provided

Presence of Fe-Al binary oxide adsorbent cake layer in ceramic membrane filtration and their impact for removal of HA and BSA.

Science.gov (United States)

Kim, Kyung-Jo; Jang, Am

2018-04-01

To enhance the removal of natural organic matter (NOM) in ceramic (Ce) membrane filtration, an iron-aluminum binary oxide (FAO) was applied to the ceramic membrane surface as the adsorbent cake layer, and it was compared with heated aluminum oxide (HAO) for the evaluation of the control of NOM. Both the HAO and FAO adsorbent cake layers efficiently removed the NOM regardless of NOM's hydrophobic/hydrophilic characteristics, and the dissolved organic carbon (DOC) removal in NOM for FAO was 1-1.12 times greater than that for HAO, which means FAO was more efficient in the removal of DOC in NOM. FAO (0.03 μm), which is smaller in size than HAO (0.4 μm), had greater flux reduction than HAO. The flux reduction increased as the filtration proceeded because most of the organic foulants (colloid/particles and soluble NOM) were captured by the adsorbent cake layer, which caused fouling between the membrane surface and the adsorbent cake layer. However, no chemically irreversible fouling was observed on the Ce membrane at the end of the FAO adsorbent cake layer filtration. This means that a stable adsorbent cake layer by FAO formed on the Ce membrane, and that the reduced pure water flux of the Ce membrane, resulting from the NOM fouling, can easily be recovered through physicochemical cleaning. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamic mechanical analysis of binary and ternary polymer blends based on nylon copolymer/EPDM rubber and EPM grafted maleic anhydride compatibilizer

Directory of Open Access Journals (Sweden)

2007-10-01

Full Text Available The dynamic mechanical properties such as storage modulus, loss modulus and damping properties of blends of nylon copolymer (PA6,66 with ethylene propylene diene (EPDM rubber was investigated with special reference to the effect of blend ratio and compatibilisation over a temperature range –100°C to 150°C at different frequencies. The effect of change in the composition of the polymer blends on tanδ was studied to understand the extent of polymer miscibility and damping characteristics. The loss tangent curve of the blends exhibited two transition peaks, corresponding to the glass transition temperature (Tg of individual components indicating incompatibility of the blend systems. The morphology of the blends has been examined by using scanning electron microscopy. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends. Finally, attempts have been made to compare the experimental data with theoretical models.

Predicting the composition of red wine blends using an array of multicomponent Peptide-based sensors.

Science.gov (United States)

Ghanem, Eman; Hopfer, Helene; Navarro, Andrea; Ritzer, Maxwell S; Mahmood, Lina; Fredell, Morgan; Cubley, Ashley; Bolen, Jessica; Fattah, Rabia; Teasdale, Katherine; Lieu, Linh; Chua, Tedmund; Marini, Federico; Heymann, Hildegarde; Anslyn, Eric V

2015-05-20

Differential sensing using synthetic receptors as mimics of the mammalian senses of taste and smell is a powerful approach for the analysis of complex mixtures. Herein, we report on the effectiveness of a cross-reactive, supramolecular, peptide-based sensing array in differentiating and predicting the composition of red wine blends. Fifteen blends of Cabernet Sauvignon, Merlot and Cabernet Franc, in addition to the mono varietals, were used in this investigation. Linear Discriminant Analysis (LDA) showed a clear differentiation of blends based on tannin concentration and composition where certain mono varietals like Cabernet Sauvignon seemed to contribute less to the overall characteristics of the blend. Partial Least Squares (PLS) Regression and cross validation were used to build a predictive model for the responses of the receptors to eleven binary blends and the three mono varietals. The optimized model was later used to predict the percentage of each mono varietal in an independent test set composted of four tri-blends with a 15% average error. A partial least square regression model using the mouth-feel and taste descriptive sensory attributes of the wine blends revealed a strong correlation of the receptors to perceived astringency, which is indicative of selective binding to polyphenols in wine.

Predicting the Composition of Red Wine Blends Using an Array of Multicomponent Peptide-Based Sensors

Directory of Open Access Journals (Sweden)

Eman Ghanem

2015-05-01

Full Text Available Differential sensing using synthetic receptors as mimics of the mammalian senses of taste and smell is a powerful approach for the analysis of complex mixtures. Herein, we report on the effectiveness of a cross-reactive, supramolecular, peptide-based sensing array in differentiating and predicting the composition of red wine blends. Fifteen blends of Cabernet Sauvignon, Merlot and Cabernet Franc, in addition to the mono varietals, were used in this investigation. Linear Discriminant Analysis (LDA showed a clear differentiation of blends based on tannin concentration and composition where certain mono varietals like Cabernet Sauvignon seemed to contribute less to the overall characteristics of the blend. Partial Least Squares (PLS Regression and cross validation were used to build a predictive model for the responses of the receptors to eleven binary blends and the three mono varietals. The optimized model was later used to predict the percentage of each mono varietal in an independent test set composted of four tri-blends with a 15% average error. A partial least square regression model using the mouth-feel and taste descriptive sensory attributes of the wine blends revealed a strong correlation of the receptors to perceived astringency, which is indicative of selective binding to polyphenols in wine.

Elaboration, characterization and application of polysulfone and polyacrylic acid blends as ultrafiltration membranes for removal of some heavy metals from water.

Science.gov (United States)

Mbareck, Chamekh; Nguyen, Quang Trong; Alaoui, Ouafa Tahiri; Barillier, Daniel

2009-11-15

Polysulfone (PSf)/polyacrylic acid ultrafiltration (PSf/PAA) membranes were prepared from a polymer blend in dimethylformamide by coagulation in water according to the wet phase inversion method. Immobilization of water-soluble PAA within the non-soluble PSf matrix was proven by the increase of ion exchange capacity and the intensity of the carboxyl groups' peak with the increase of PAA content as shown by Fourier transform infrared spectra. These results lead to consider that PSf and PAA form a semi-interpenetrating polymer networks. The obtained membranes showed a decrease of mean surface-pore sizes, the overall porosity and the hydraulic permeability with the increase in PAA content. Such results were imputed to the morphologic modifications of PSf film with the immobilization of increasing PAA amount. PSf/PAA membranes showed high lead, cadmium and chromium rejection which reaches 100% at pH superior to 5.7 and a low rejection at low pH. Moreover, the heavy metal rejection decreases with feed solution concentration and applied pressure increases. These behaviors were attributed to the role of carboxylic groups in ion exchange or complexation. As a matter of fact, the strong lead ion-PAA interactions were revealed by the scanning electron microscopy with energy dispersive X-rays (SEM-EDX).

Topological and morphological analysis of gamma rays irradiated chitosan-poly (vinyl alcohol) blends using atomic force microscopy

Science.gov (United States)

Bhatt, Rinkesh; Bisen, D. S.; Bajpai, R.; Bajpai, A. K.

2017-04-01

In the present communication, binary blends of poly (vinyl alcohol) (PVA) and chitosan (CS) were prepared by solution cast method and the roughness parameters of PVA, native CS and CS-PVA blend films were determined using atomic force microscopy (AFM). Moreover, the changes in the morphology of the samples were also investigated after irradiation of gamma rays at absorbed dose of 1 Mrad and 10 Mrad for the scanning areas of 5×5 μm2, 10×10 μm2 and 20×20 μm2. Amplitude, statistical and spatial parameters, including line, 3D and 2D image profiles of the experimental surfaces were examined and compared to un-irradiated samples. For gamma irradiated CS-PVA blends the larger waviness over the surface was found as compared to un-irradiated CS-PVA blends but the values of average roughness for both the films were found almost same. The coefficient of skewness was positive for gamma irradiated CS-PVA blends which revealed the presence of more peaks than valleys on the blend surfaces.

Carbon capture from natural gas using multi-walled CNTs based mixed matrix membranes.

Science.gov (United States)

Hussain, Abid; Farrukh, Sarah; Hussain, Arshad; Ayoub, Muhammad

2017-12-05

Most of the polymers and their blends, utilized in carbon capture membranes, are costly, but cellulose acetate (CA) being inexpensive is a lucrative choice. In this research, pure and mixed matrix membranes (MMMs) have been fabricated to capture carbon from natural gas. Polyethylene glycol (PEG) has been utilized in the fabrication of membranes to modify the chain flexibility of polymers. Multi-walled carbon nanotubes (MWCNTs) provide mechanical strength, thermal stability, an extra free path for CO 2 molecules and augment CO 2 /CH 4 selectivity. Membranes of pure CA, CA/PEG blend of different PEG concentrations (5%, 10%, 15%) and CA/PEG/MWCNTs blend of 10% PEG with different MWCNTs concentrations (5%, 10%, 15%) were prepared in acetone using solution casting techniques. Fabricated membranes were characterized using SEM, TGA and tensile testing. Permeation results revealed remarkable improvement in CO 2 /CH 4 selectivity. In single gas experiments, CO 2 /CH 4 selectivity is enhanced 8 times for pure membranes containing 10% PEG and 14 times for MMMs containing 10% MWCNTs. In mix gas experiments, the CO 2 /CH 4 selectivity is increased 13 times for 10% PEG and 18 times for MMMs with 10% MWCNTs. Fabricated MMMs have a tensile strength of 13 MPa and are more thermally stable than CA membranes.

Influence of non-covalent modification of multiwalled carbon nanotubes on the crystallization behaviour of binary blends of polypropylene and polyamide 6.

Science.gov (United States)

Mukhopadhyay, Nabaneeta; Panwar, Ajay S; Kumar, Gulshan; Samajdar, I; Bhattacharyya, Arup R

2015-02-14

Blends of polypropylene (PP) and polyamide 6 (PA6) with multiwalled carbon nanotubes (MWNTs) were prepared using different processing strategies in a twin-screw micro-compounder. The effect of MWNTs on the crystallization behaviour of the PP phase and the PA6 phase of the blend has been investigated through non-isothermal crystallization studies by differential scanning calorimetric analysis. Furthermore, the effect of the addition of the compatibilizer (PP-g-MA) and the modification of MWNTs (m-MWNTs) with a non-covalent organic modifier (Li-salt of 6 amino hexanoic acid, Li-AHA) has also been studied in context to the crystallization behaviour of the PP and PA6 phase in the blend. The crystallization studies have indicated a significant increase in bulk crystallization temperature of the PP phase in the blend in the presence of MWNTs. Moreover, the formation of 'trans-lamellar crystalline' structure consisting of PA6 'trans-crystalline lamellae' on MWNTs surface was facilitated in the case of blends prepared via 'protocol 2' as compared to the corresponding blends prepared via 'protocol 1'. Wide angle X-ray diffraction analysis has showed the existence of a β-polymorph of the PP phase due to incorporation of the PA6 phase in the blend. Addition of MWNTs in the blends has facilitated further β-crystalline structure formation of the PP phase. In the presence of m-MWNTs, a higher β-fraction was observed in the PP phase as compared to the blend with pristine MWNTs. Addition of PP-g-MA has suppressed the β-phase formation in the PP phase in the blend. X-ray bulk texture analysis revealed that incorporation of PA6 as well as pristine/modified MWNTs has influenced the extent of orientation of the PP chains towards specific crystalline planes in various blend compositions of PP and PA6.

Modified SPEEK membranes for direct ethanol fuel cell

KAUST Repository

Maab, Husnul

2010-07-01

Membranes with low ethanol crossover were prepared aiming their application for direct ethanol fuel cell (DEFC). They were based on (1) sulfonated poly(ether ether ketone) (SPEEK) coated with carbon molecular sieves (CMS) and (2) on SPEEK/PI homogeneous blends. The membranes were characterized concerning their water and ethanol solution uptake, water and ethanol permeability in pervaporation experiments and their performance in DEFC tests. The ethanol permeabilities for the CMS-coated (180 nm and 400 nm thick layers) SPEEK were 8.5 and 3.1 x 10(-10) kg m s(-1) m(-2) and for the homogeneous SPEEK/PI blends membranes with 10, 20 and 30 wt.% of PI were 4.4, 1.0 and 0.4 x 10(-10) kg m s(-1) m(-2) respectively, which is 2- to 50-fold lower than that for plain SPEEK (19 x 10(-10) kg m s(-1) m(-2)). Particularly the SPEEK/PI membranes had substantially better performance than Nafion 117 membranes in DEFC tests at 60 degrees C and 90 degrees C. (C) 2010 Elsevier B.V. All rights reserved.

Exciplex dynamics in a blend of π-conjugated polymers with electron donating and accepting properties: MDMO-PPV and PCNEPV

NARCIS (Netherlands)

Offermans, T.; Hal, van P.A.; Meskers, S.C.J.; Koetse, M.M.; Janssen, R.A.J.

2005-01-01

The photophysical properties of a solution processed blend of two semiconducting polymers with electron donating and electron accepting properties, respectively, as used in polymer photovoltaic devices have been investigated. We show that in the binary mixture of

Formulation and characterization of poly(propylacrylic acid)/poly(lactic-co-glycolic acid) blend microparticles for pH-dependent membrane disruption and cytosolic delivery.

Science.gov (United States)

Fernando, Lawrence P; Lewis, Jamal S; Evans, Brian C; Duvall, Craig L; Keselowsky, Benjamin G

2018-04-01

Poly(lactic-co-glycolic acid) (PLGA) is widely used as a vehicle for delivery of pharmaceutically relevant payloads. PLGA is readily fabricated as a nano- or microparticle (MP) matrix to load both hydrophobic and hydrophilic small molecular drugs as well as biomacromolecules such as nucleic acids and proteins. However, targeting such payloads to the cell cytosol is often limited by MP entrapment and degradation within acidic endolysosomes. Poly(propylacrylic acid) (PPAA) is a polyelectrolyte polymer with the membrane disruptive capability triggered at low pH. PPAA has been previously formulated in various carrier configurations to enable cytosolic payload delivery, but requires sophisticated carrier design. Taking advantage of PPAA functionality, we have incorporated PPAA into PLGA MPs as a simple polymer mixture to enhance cytosolic delivery of PLGA-encapsulated payloads. Rhodamine loaded PLGA and PPAA/PLGA blend MPs were prepared by a modified nanoprecipitation method. Incorporation of PPAA into PLGA MPs had little to no effect on the size, shape, or loading efficiency, and evidenced no toxicity in Chinese hamster ovary epithelial cells. Notably, incorporation of PPAA into PLGA MPs enabled pH-dependent membrane disruption in a hemolysis assay, and a three-fold increased endosomal escape and cytosolic delivery in dendritic cells after 2 h of MP uptake. These results demonstrate that a simple PLGA/PPAA polymer blend is readily fabricated into composite MPs, enabling cytosolic delivery of an encapsulated payload. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1022-1033, 2018. © 2017 Wiley Periodicals, Inc.

Investigation of polyvinylchloride and cellulose acetate blend membranes for desalination

Science.gov (United States)

El-Gendi, Ayman; Abdallah, Heba; Amin, Ashraf; Amin, Shereen Kamel

2017-10-01

The pollution of water resources, severe climate changes, rapid population growth, increasing agricultural demands, and rapid industrialization insist the development of innovative technologies for generating potable water. Polyvinylchloride/cellulose acetate (PVC/CA) membranes were prepared using phase inversion technique for seawater reverse osmosis (SWRO). The membrane performance was investigated using Red Sea water (El-Ein El-Sokhna-Egypt). The membrane performance indicated that the prepared membranes were endowed to work under high pressure; increasing in feeding operating pressure led to increase permeate flux and rejection. Increasing feed operating pressure from zero to 40 bar led to increase in the salt rejection percent. Salt rejection percent reached to 99.99% at low feed concentration 5120 ppm and 99.95% for Red Sea water (38,528 ppm). The prepared membranes were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrophotometry, and mechanical properties. SEM, FTIR and mechanical results were used to distinguish the best membrane for desalination. According to characterization results, one prepared membrane was selected to run performance test in desalination testing unit. The membrane (M3) showed excellent performance and stability under different operating conditions and during the durability test for 36 days.

Modeling of Multicomponent Mixture Separation Processes Using Hollow fiber Membrane

Energy Technology Data Exchange (ETDEWEB)

Kim, Sin-Ah; Kim, Jin-Kuk; Lee, Young Moo; Yeo, Yeong-Koo [Hanyang University, Seoul (Korea, Republic of)

2015-02-15

So far, most of research activities on modeling of membrane separation processes have been focused on binary feed mixture. But, in actual separation operations, binary feed is hard to find and most separation processes involve multicomponent feed mixture. In this work models for membrane separation processes treating multicomponent feed mixture are developed. Various model types are investigated and validity of proposed models are analysed based on experimental data obtained using hollowfiber membranes. The proposed separation models show quick convergence and exhibit good tracking performance.

The blending and segregation of coal for the U.K. industrial market

Energy Technology Data Exchange (ETDEWEB)

McGlinchey, D.; Jones, M.G.; Marjanovic, P. [Glasgow Caledonian Univ. (United Kingdom). Dept. of Physical Sciences

1999-09-01

The two most common methods of 'blending' industrial coals is either by use of feeder belts discharging onto a central conveyor belt, or by a compartment hopper discharging onto a common belt. These two methodologies were shown to give very similar levels of variance in the proportioning of component coals, over a wide range of discharge conditions. Limited work suggested that belt sampling from the end of the belt gave similar results to the stopped belt and frame technique. The segregation found in heaps formed from binary mixtures of coals was quantified by various statistical methods. These results demonstrated that very high levels of segregation can be expected in almost any heap formed when material is discharged from the belt in either of the two 'blending' methods described above. This can reasonably be expected to be a major factor in the inconsistent supply of a specified blend to a consumer. (orig.)

Electrospun nanofibrous SF/P(LLA-CL membrane: a potential substratum for endothelial keratoplasty

Directory of Open Access Journals (Sweden)

Chen JZ

2015-05-01

Full Text Available Junzhao Chen,1,* Chenxi Yan,1,* Mengyu Zhu,1,* Qinke Yao,1 Chunyi Shao,1 Wenjuan Lu,1 Jing Wang,2 Xiumei Mo,2 Ping Gu,1 Yao Fu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry and Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-Ɛ-caprolactone (P(LLA-CL has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty.Methods: Five scaffolds containing different SF:P(LLA-CL blended ratios (100:0, 75:25, 50:50, 25:75, 0:100 were manufactured. A human corneal endothelial (B4G12 cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test, cell proliferation (Ki-67, BrdU staining, and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction.Results: Different blended ratios of scaffolds

Ternary Blend Composed of Two Organic Donors and One Acceptor for Active Layer of High-Performance Organic Solar Cells.

Science.gov (United States)

Lee, Jong Won; Choi, Yoon Suk; Ahn, Hyungju; Jo, Won Ho

2016-05-04

Ternary blends composed of two donor absorbers with complementary absorptions provide an opportunity to enhance the short-circuit current and thus the power conversion efficiency (PCE) of organic solar cells. In addition to complementary absorption of two donors, ternary blends may exhibit favorable morphology for high-performance solar cells when one chooses properly the donor pair. For this purpose, we develop a ternary blend with two donors (diketopyrrolopyrrole-based polymer (PTDPP2T) and small molecule ((TDPP)2Ph)) and one acceptor (PC71BM). The solar cell made of a ternary blend with 10 wt % (TDPP)2Ph exhibits higher PCE of 7.49% as compared with the solar cells with binary blends, PTDPP2T:PC71BM (6.58%) and (TDPP)2Ph:PC71BM (3.21%). The higher PCE of the ternary blend solar cell is attributed mainly to complementary absorption of two donors. However, a further increase in (TDPP)2Ph content in the ternary blend (>10 wt %) decreases the PCE. The ternary blend with 10 wt % (TDPP)2Ph exhibits well-developed morphology with narrow-sized fibrils while the blend with 15 wt % (TDPP)2Ph shows phase separation with large-sized domains, demonstrating that the phase morphology and compatibility of ternary blend are important factors to achieve a high-performance solar cell made of ternary blends.

Studies of PVC/ENR blends: blend compositions

International Nuclear Information System (INIS)

Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan; Nasir, M.; Baharin, A.

2002-01-01

Blends of poly(vinyl chloride/epoxidized natural rubber (PVC/ENR) were prepared by using Bra bender Plasticorder at compositions ranging from 0-100% PVC. They were blended at 150 degree C mixing temperature, 50 rpm rotor speed and 10 minutes mixing time. The blends were characterized for tensile strength , elongation at break, glass transition temperatures and Fourier transform infra red spectroscopy (FTIR). Results revealed that as the PVC content increases the blend behaviour changes from elastomeric to glassy. However the blends found to be compatible at all compositions. (Author)

Phase boundary in compatible and incompatible polymer blends studied by micro indentation test and microscopic observations

International Nuclear Information System (INIS)

Mina, M. F.; Akhtar, F.; Haque, M.E.

2003-10-01

The phase boundary of incompatible polymer blends such as poly (methyl methacrylate) (PMMA)/natural rubber (NR) and polyestyrene (PS)/NR as well as compatible blends such as PMMA/NR/epoxidizer NR (compatibilizer) and PS/NR/styrene-butadiene-styrene (SBS) block copolymer (compatibilizer) was studied by means of microhardness (H) technique and microscopy. Solution grown films of neat PMMA, PS and blended films of PMMA/NR, PS/NR, PMMA/NR/ENR and PS/NR/SBS were cast using a common solvent (toluene). While the neat PMMA and PS provide constant hardness values of 178 and 173 MPa, respectively, the binary (incompatible) and the ternary (compatible) blends show a conspicuous H-decrease (PMMA/NR=140 MPa, PS/NR=167 MPa, PMMA/NR/ENR=109 MPa and PS/NR/SBS=127 MPa). Scanning electron microscopy and optical microscopy reveal clear difference of the phase boundary of compatible (smooth boundary) and incompatible (sharp boundary) blends. Besides, the compatibilizer blends are characterised by the thinnest phase boundary (30 μm), which is found about 60 μm in the incompatible blends, showing a final hardness value that demonstrates the compatibilizer to be smoothly distributed in the interface between the two blend components. Results highlight that microindentation technique, in combination with microscopic observations, is a sensitive tool for studying the breadth and quality of the interphase boundary in non- or compatibilized polymer blends and other inhomogeneous materials. (author)

Transport through track etched polymeric blend membrane

Indian Academy of Sciences (India)

Unknown

Department of Physics, University of Rajasthan, Jaipur 302 004, India. MS received 10 June 2005 ... Both the track and bulk etching takes place in the irradiated membrane. ... using rotating flywheel attachment, the details having been given ...

Self-Assembled Asymmetric Block Copolymer Membranes: Bridging the Gap from Ultra- to Nanofiltration

KAUST Repository

Yu, Haizhou; Qiu, Xiaoyan; Moreno, Nicolas; Ma, Zengwei; Calo, Victor M.; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

2015-01-01

-assembled block copolymer membranes to below 5 nm without post-treatment. It is now reported that the self-assembly of blends of two chemically interacting copolymers can lead to highly porous membranes with pore diameters as small as 1.5 nm. The membrane

Application of a radioactive sourced semi portable X-ray spectrometer to the solution of binary mix compositions

International Nuclear Information System (INIS)

Butcher, B.M.

1988-01-01

In many cases it is far more economically viable to transport individual constituents to a blending plant and produce a series of custom made products than to manufacture at site. This situation exists in many heavy chemical industries or on large building sites. In the cement industry inter-mixed or interground blends containing slag, fly ash, or limestone are produced. These mixes are designed to enhance certain physical properties and to reduce costs. This paper summarises experience of the application of portable isotope source X-ray analysers in achieving quality control of binary mixes

Interstitial micelles in binary blends of A B A triblock copolymers and homopolymers

Science.gov (United States)

Wołoszczuk, S.; Banaszak, M.

2018-01-01

We investigate triblock-homopolymer blends of types A1BA2/A and A1BA2/B, using a lattice Monte Carlo method. While the simulated triblock chains are compositionally symmetric in terms of the A-to-B volume ratio, the A1 block is significantly shorter than the A2 block. For the pure A1BA2 melt and the A1BA2 solutions in selective solvent the phase behavior is relatively well known, including existence and stability of the interstitial micelles which were discovered in previous Monte Carlo simulations. In this paper we study the stability of the interstitial micelles as a function of triblock volume fraction in selective homopolymers of either type A or type B, using two significantly different homopolymer chain lengths. We found that adding selective homopolymer of type A shifts the stability of the interstitial micelles into significantly higher temperatures. We also obtained, via self-assembly, intriguing new nanostructures which can be identified as ordered truncated octahedra. Finally, we established that the phase behavior of the triblock-homopolymer blends depends relatively weakly on the chain length of the added homopolymer.

High flux polyethersulfone-polyimide blend hollow fiber membranes for gas separation

NARCIS (Netherlands)

Kapantaidakis, G.; Koops, G.H.

2002-01-01

In this work, the preparation of gas separation hollow fibers based on polyethersulfone Sumikaexcel (PES) and polyimide Matrimid 5218 (PI) blends, for three different compositions (i.e. PES/PI: 80/20, 50/50 and 20/80 wt.%), is reported. The dry/wet spinning process has been applied to prepare

Hydrophilicity improvement in polyphenylsulfone nanofibrous filtration membranes through addition of polyethylene glycol

Science.gov (United States)

Kiani, Shirin; Mousavi, Seyed Mahmoud; Shahtahmassebi, Nasser; Saljoughi, Ehsan

2015-12-01

Novel hydrophilic polyphenylsulfone (PPSU) nanofibrous membrane was prepared by electrospinning of the PPSU solution blended with polyethylene glycol 400 (PEG 400). The influence of the PEG concentration on the membrane characteristics was studied using scanning electron microscopy (SEM), water contact angle measurement, and tensile test. Filtration performance of the membranes was investigated by measurement of pure water flux (PWF) and determination of the rejection values of the pollution indices during treatment of canned beans production wastewater. According to the results, blending the PPSU solution with 10 wt.% PEG 400 resulted in formation of a nanofibrous membrane with high porosity and increased mechanical strength which exhibited a low water contact angle of 8.9° and high water flux of 7920 L/m2h. Flux recovery of the mentioned membrane which was assessed by filtration of a solution containing bovine serum albumin (BSA) was 83% indicating a noticeable antifouling property.

Observations of crystallization and melting in poly(ethylene oxide)/poly(methyl methacrylate) blends by hot-stage atomic-force microscopy

NARCIS (Netherlands)

Pearce, R.; Vancso, Gyula J.

1998-01-01

The binary blend of poly(ethylene oxide)/atactic poly(methyl methacrylate) is examined using hot-stage atomic-force microscopy (AFM) in conjunction with differential scanning calorimetry and optical microscopy. It was found possible to follow in real time the melting process, which reveals itself to

Strategies for cell manipulation and skeletal tissue engineering using high-throughput polymer blend formulation and microarray techniques.

Science.gov (United States)

Khan, Ferdous; Tare, Rahul S; Kanczler, Janos M; Oreffo, Richard O C; Bradley, Mark

2010-03-01

A combination of high-throughput material formulation and microarray techniques were synergistically applied for the efficient analysis of the biological functionality of 135 binary polymer blends. This allowed the identification of cell-compatible biopolymers permissive for human skeletal stem cell growth in both in vitro and in vivo applications. The blended polymeric materials were developed from commercially available, inexpensive and well characterised biodegradable polymers, which on their own lacked both the structural requirements of a scaffold material and, critically, the ability to facilitate cell growth. Blends identified here proved excellent templates for cell attachment, and in addition, a number of blends displayed remarkable bone-like architecture and facilitated bone regeneration by providing 3D biomimetic scaffolds for skeletal cell growth and osteogenic differentiation. This study demonstrates a unique strategy to generate and identify innovative materials with widespread application in cell biology as well as offering a new reparative platform strategy applicable to skeletal tissues. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Characteristics of the Nafion (registered) - impregnated polycarbonate composite membranes for PEMFCs

International Nuclear Information System (INIS)

Kim, Ki-Hwan; Ahn, Sang-Yeoul; Oh, In-Hwan; Ha, Heung Yong; Hong, Seong-Ahn; Kim, Moon-Sun; Lee, Youngkwan; Lee, Yong-Chul

2004-01-01

In this work, polycarbonate composite membranes were prepared for proton exchange membrane fuel cells (PEMFCs). In the preparation of membranes, a small amount of poly(ethylene glycol) (PEG) was blended with polycarbonate (PC) solution and then cast to make membranes. PEG contained in the membrane was removed by the high solubility of supercritical CO 2 to afford porosity in the membrane. Then, porous PC membranes were soaked in Nafion (registered) solution to yield the PC/Nafion (registered) composite membranes. The PC composite membrane had lower ion conductivity but higher conductance than Nafion (registered)

LDPE/PHB blends filled with castor oil cake

Science.gov (United States)

Burlein, Gustavo A.; Rocha, Marisa C. G.

2015-05-01

The response surface methodology (RSM) is a collection of mathematical techniques useful for developing, improving and optimizing process. In this study, RSM technique was applied to evaluate the effect of the components proportion on the mechanical properties of low density polyethylene (LDPE)/ poly (3-hydroxy-butyrate) (PHB) blends filled with castor oil cake (CC). The blends were prepared by melt mixing in a twin screw extruder. Low density polyethylene, poly (3-hydroxy-butyrate) and castor oil pressed cake were represented by the input variables designated as LDPE, PHB and CC, respectively. As it was desirable to consider the largest LDPE content in the ternary system, the components of the mixture were subjected to the following constraints: 0.7 ≤ LDPE ≤ 1.0, 0≤ PHB≤0.3 e 0 ≤ CC ≤0.3. The mechanical properties of the different mixtures were determined by conventional ASTM tests and were evaluated through analysis of variance performed by the Minitab software. Some polynomial equations were tested in order to describe the mechanical behavior of the samples. The quadratic model in pseudo components was selected for describing the tensile behavior because it was the most efficient from a statistical point of view (p-value ≤ 0.05; coefficient of determination (r2) close to 1 and variation inflation factor (VIF) values PHB or CC. The tensile strength values of binary mixtures of LDPE lie in the range from 8.9 to 10 MPa. As some commercial grades of LDPE have mechanical strength in this range, it may be inferred that the addition of a certain amount of PHB or CC to LDPE may be considered as a possibility for obtaining LDPE based materials with increased susceptibility to biodegradation. The cubic model in pseudo components was selected for describe the flexural strength of the samples because it was the most adequate from a statistical point of view. However, the linear model in pseudo components was the most efficient to describe the flexural modulus

Blend or not to blend: a study investigating faculty members perceptions of blended teaching

Directory of Open Access Journals (Sweden)

Mehmet A Ocak

2010-12-01

Full Text Available This study examined faculty members’ perceptions of blended teaching from several perspectives. A total of 73 faculty members in Turkish Higher Education context participated in the study by completing an online survey that combined quantitative and qualitative approaches. Based on a data analysis, the faculty members’ perceptions were sorted into six categories: (a satisfaction with blended teaching, (b perceived impact on the role of the faculty, (c perceived impact on student learning, (d perceived impact on student motivation, (e advantages of blended teaching, and (f disadvantages of blended teaching. Findings indicated that faculty members were likely to agree that blended teaching provides a high degree of satisfaction and that it requires more time and commitment from the faculty. The faculty members perceived that blended teaching improves student learning and, to some extent, improves motivation. The faculty members also emphasized the importance of institutional support and the use of technology to mitigate student problems. This study presents these faculty members’ perceptions, which are helpful for those planning to implement a blended teaching approach, and makes suggestions for trouble-shooting and taking advantage of the opportunities in a blended environment successfully.

PVA/Polysaccharides Blended Films: Mechanical Properties

Directory of Open Access Journals (Sweden)

Fábio E. F. Silva

2013-01-01

Full Text Available Blends of polyvinyl alcohol (PVA and angico gum (AG and/or cashew gum (CG were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO. The films presented thickness varying from 70 to 140 μm (PVA/AG and 140 to 200 μm (PVA/CG. Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher values of tensile strength (TS and elastic modulus (EM were observed in the film. On the other hand, PVA/CG and PVA/CG-AG presented the highest value of percentage of elongation (E%. Pearson’s Correlation Analysis revealed a positive correlation between TS and EM and a negative correlation between E% and EM. The PVA/CG film presented mechanical properties very similar to MBO, with the advantage of a higher E% (11.96 than MBO (2.94. The properties of the PVA blended films depended on the polysaccharide added in the blend, as well as the acid used as a catalyst. However, all produced films presented interesting mechanical characteristics which enables several biotechnological applications.

Influence of electrostatic interactions on the morphology and properties of blends containing perfluorinated ionomers

Science.gov (United States)

Taylor, Eric Paul

2002-01-01

The first goal of this research project was to investigate the influence of the electrostatic interactions within the ion-containing domains of Nafion RTM perfluorosulfonate ionomer (PFSI) on the morphology and resultant properties of blend systems with poly(propylene imine) dendrimers of a variety of generational sizes and poly(vinylidene fluoride) (PVDF). Perfluorosulfonate ionomers (PFSIs) are a commercially successful class of semi-crystalline, ion-containing polymers whose most extensive application is in use as a polymer electrolytic membrane in fuel cell applications. NafionRTM was blended and high temperature solution processed with poly(propylene imine) dendrimer as the minor component in order to increase the efficiency of direct methanol fuel cells by decreasing methanol crossover without significant loss of protonic conductivity. The preferential insertion of the dendrimer into the ionic cluster due to proton transfer reactions and the creation of ammonium-sulfonate ion pairs served to alter the transport properties through the ionic network of the membrane. In the second major system investigated, blends of poly(vinylidene fluoride) (PVDF) with NafionRTM, a perfluorosulfonate ionomer, have been prepared and examined in terms of the crystallization kinetics and crystal morphology of the PVDF component in the blend. DSC analysis showed faster rates of bulk crystallization when PVDF was crystallized in the presence of Na+-form NafionRTM suggesting a high degree of phaseseparation in this blend system and an increase in the nucleation density. NafionRTM neutralized with alkylammonium-form counterions display an increase in blend compatibility with PVDF with an increase in the alkylammonium counterion size. As the alkylammonium counterion size increases, the strength of the electrostatic network within the ionic domains of Nafion RTM decrease resulting in a reduction in the driving force for ionic aggregation. Thus, a decrease is observed in the crystal

Equilibrating high-molecular-weight symmetric and miscible polymer blends with hierarchical back-mapping

Science.gov (United States)

Ohkuma, Takahiro; Kremer, Kurt; Daoulas, Kostas

2018-05-01

Understanding properties of polymer alloys with computer simulations frequently requires equilibration of samples comprised of microscopically described long molecules. We present the extension of an efficient hierarchical backmapping strategy, initially developed for homopolymer melts, to equilibrate high-molecular-weight binary blends. These mixtures present significant interest for practical applications and fundamental polymer physics. In our approach, the blend is coarse-grained into models representing polymers as chains of soft blobs. Each blob stands for a subchain with N b microscopic monomers. A hierarchy of blob-based models with different resolution is obtained by varying N b. First the model with the largest N b is used to obtain an equilibrated blend. This configuration is sequentially fine-grained, reinserting at each step the degrees of freedom of the next in the hierarchy blob-based model. Once the blob-based description is sufficiently detailed, the microscopic monomers are reinserted. The hard excluded volume is recovered through a push-off procedure and the sample is re-equilibrated with molecular dynamics (MD), requiring relaxation on the order of the entanglement time. For the initial method development we focus on miscible blends described on microscopic level through a generic bead-spring model, which reproduces hard excluded volume, strong covalent bonds, and realistic liquid density. The blended homopolymers are symmetric with respect to molecular architecture and liquid structure. To parameterize the blob-based models and validate equilibration of backmapped samples, we obtain reference data from independent hybrid simulations combining MD and identity exchange Monte Carlo moves, taking advantage of the symmetry of the blends. The potential of the backmapping strategy is demonstrated by equilibrating blend samples with different degree of miscibility, containing 500 chains with 1000 monomers each. Equilibration is verified by comparing

Auto-Ignition of Iso-Stoichiometric Blends of Gasoline-Ethanol-Methanol (GEM) in SI, HCCI and CI Combustion Modes

KAUST Repository

Waqas, Muhammad

2017-03-28

Gasoline-ethanol-methanol (GEM) blends, with constant stoichiometric air-to-fuel ratio (iso-stoichiometric blending rule) and equivalent to binary gasoline-ethanol blends (E2, E5, E10 and E15 in % vol.), were defined to investigate the effect of methanol and combined mixtures of ethanol and methanol when blended with three FACE (Fuels for Advanced Combustion Engines) Gasolines, I, J and A corresponding to RON 70.2, 73.8 and 83.9, respectively, and their corresponding Primary Reference Fuels (PRFs). A Cooperative Fuel Research (CFR) engine was used under Spark Ignition and Homogeneous Charge Compression Ignited modes. An ignition quality tester was utilized in the Compression Ignition mode. One of the promising properties of GEM blends, which are derived using the iso-stoichiometric blending rule, is that they maintain a constant octane number, which has led to the introduction of methanol as a drop-in fuel to supplement bio-derived ethanol. A constant RON/HCCI fuel number/derived Research octane number property was observed in all three combustion modes for high RON fuels, but for low RON fuels, the iso-stoichiometric blending rule for constant octane number did not appear to be valid. The chemical composition and octane number of the base fuel also influenced the behavior of the GEM blends under different conditions.

Auto-Ignition of Iso-Stoichiometric Blends of Gasoline-Ethanol-Methanol (GEM) in SI, HCCI and CI Combustion Modes

KAUST Repository

Waqas, Muhammad; Naser, Nimal; Sarathy, Mani; Feijs, Jeroen; Morganti, Kai; Nyrenstedt, Gustav; Johansson, Bengt

2017-01-01

Gasoline-ethanol-methanol (GEM) blends, with constant stoichiometric air-to-fuel ratio (iso-stoichiometric blending rule) and equivalent to binary gasoline-ethanol blends (E2, E5, E10 and E15 in % vol.), were defined to investigate the effect of methanol and combined mixtures of ethanol and methanol when blended with three FACE (Fuels for Advanced Combustion Engines) Gasolines, I, J and A corresponding to RON 70.2, 73.8 and 83.9, respectively, and their corresponding Primary Reference Fuels (PRFs). A Cooperative Fuel Research (CFR) engine was used under Spark Ignition and Homogeneous Charge Compression Ignited modes. An ignition quality tester was utilized in the Compression Ignition mode. One of the promising properties of GEM blends, which are derived using the iso-stoichiometric blending rule, is that they maintain a constant octane number, which has led to the introduction of methanol as a drop-in fuel to supplement bio-derived ethanol. A constant RON/HCCI fuel number/derived Research octane number property was observed in all three combustion modes for high RON fuels, but for low RON fuels, the iso-stoichiometric blending rule for constant octane number did not appear to be valid. The chemical composition and octane number of the base fuel also influenced the behavior of the GEM blends under different conditions.

Improved PVDF membrane performance by doping extracellular polymeric substances of activated sludge.

Science.gov (United States)

Guan, Yan-Fang; Huang, Bao-Cheng; Qian, Chen; Wang, Long-Fei; Yu, Han-Qing

2017-04-15

Polyvinylidene fluoride (PVDF) membrane has been widely applied in water and wastewater treatment because of its high mechanical strength, thermal stability and chemical resistance. However, the hydrophobic nature of PVDF membrane makes it readily fouled, substantially reducing water flux and overall membrane rejection ability. In this work, an in-situ blending modifier, i.e., extracellular polymeric substances (EPS) from activated sludge, was used to enhance the anti-fouling ability of PVDF membrane. Results indicate that the pure water flux of the membrane and its anti-fouling performance were substantially improved by blending 8% EPS into the membrane. By introducing EPS, the membrane hydrophilicity was increased and the cross section morphology was changed when it interacted with polyvinl pyrrolidone, resulting in the formation of large cavities below the finger-like pores. In addition, the fraction of pores with a size of 100-500 nm increased, which was also beneficial to improving membrane performance. Surface thermodynamic calculations indicate the EPS-functionalized membrane had a higher cohesion free energy, implying its good pollutant rejection and anti-fouling ability. This work provides a simple, efficient and cost-effective method to improve membrane performance and also extends the applications of EPS. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of temperature gradient on liquid-liquid phase separation in a polyolefin blend.

Science.gov (United States)

Jiang, Hua; Dou, Nannan; Fan, Guoqiang; Yang, Zhaohui; Zhang, Xiaohua

2013-09-28

We have investigated experimentally the structure formation processes during phase separation via spinodal decomposition above and below the spinodal line in a binary polymer blend system exposed to in-plane stationary thermal gradients using phase contrast optical microscopy and temperature gradient hot stage. Below the spinodal line there is a coupling of concentration fluctuations and thermal gradient imposed by the temperature gradient hot stage. Also under the thermal gradient annealing phase-separated domains grow faster compared with the system under homogeneous temperature annealing on a zero-gradient or a conventional hot stage. We suggest that the in-plane thermal gradient accelerates phase separation through the enhancement in concentration fluctuations in the early and intermediate stages of spinodal decomposition. In a thermal gradient field, the strength of concentration fluctuation close to the critical point (above the spinodal line) is strong enough to induce phase separation even in one-phase regime of the phase diagram. In the presence of a temperature gradient the equilibrium phase diagrams are no longer valid, and the systems with an upper critical solution temperature can be quenched into phase separation by applying the stationary temperature gradient. The in-plane temperature gradient drives enhanced concentration fluctuations in a binary polymer blend system above and below the spinodal line.

OGLE-2015-BLG-0479LA,B: BINARY GRAVITATIONAL MICROLENS CHARACTERIZED BY SIMULTANEOUS GROUND-BASED AND SPACE-BASED OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Soszyński, I.; Skowron, J.; Mróz, P.; Poleski, R. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, A.; Zhu, Wei; Fausnaugh, M.; Gaudi, B. S.; Wibking, B. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Street, R. A. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Beichman, C.; Novati, S. Calchi [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Bryden, C.; Henderson, Calen B.; Shvartzvald, Y. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Carey, S. [Spitzer Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Collaboration: (The Spitzer Microlensing Team; (The OGLE Collaboration; (The RoboNet collaboration; (The MiNDSTEp Consortium; (The μ FUN Collaboration; and others

2016-09-01

We present a combined analysis of the observations of the gravitational microlensing event OGLE-2015-BLG-0479 taken both from the ground and by the Spitzer Space Telescope . The light curves seen from the ground and from space exhibit a time offset of ∼13 days between the caustic spikes, indicating that the relative lens-source positions seen from the two places are displaced by parallax effects. From modeling the light curves, we measure the space-based microlens parallax. Combined with the angular Einstein radius measured by analyzing the caustic crossings, we determine the mass and distance of the lens. We find that the lens is a binary composed of two G-type stars with masses of ∼1.0 M {sub ⊙} and ∼0.9 M {sub ⊙} located at a distance of ∼3 kpc. In addition, we are able to constrain the complete orbital parameters of the lens thanks to the precise measurement of the microlens parallax derived from the joint analysis. In contrast to the binary event OGLE-2014-BLG-1050, which was also observed by Spitzer, we find that the interpretation of OGLE-2015-BLG-0479 does not suffer from the degeneracy between (±, ±) and (±, ∓) solutions, confirming that the four-fold parallax degeneracy in single-lens events collapses into the two-fold degeneracy for the general case of binary-lens events. The location of the blend in the color–magnitude diagram is consistent with the lens properties, suggesting that the blend is the lens itself. The blend is bright enough for spectroscopy and thus this possibility can be checked from future follow-up observations.

PBI/Nafion/SiO2 hybrid membrane for high-temperature low-humidity fuel cell applications

International Nuclear Information System (INIS)

Wang, Liang; Advani, Suresh G.; Prasad, Ajay K.

2013-01-01

A novel composite membrane for fuel cell applications was prepared by incorporating SiO 2 in PBI/Nafion resin by the sol–gel method. Polybenzimidazole (PBI) was blended with Nafion to improve the membrane stability. The presence of PBI also improves the dimensional stability of the composite membrane over a wide range of hydration conditions. Being highly hygroscopic, SiO 2 enhances water absorption and retention in the membrane which improves fuel cell performance under low relative humidity conditions. Scanning electron microscopy showed that the PBI and Nafion polymers can be blended uniformly. Energy dispersive X-ray spectroscopy confirmed the presence of SiO 2 in the composite membrane. Thermal gravimetric analysis confirmed the improved thermal stability of the SiO 2 /PBI/Nafion membrane. Tensile strength, water uptake and swelling of the composite membrane were also measured at 60 °C and compared with Nafion. The fuel cell performance of the novel SiO 2 /PBI/Nafion composite membrane at 120 °C and 35% relative humidity significantly improved over a pure Nafion membrane of the same thickness

Phase-Resolved Spectroscopy of the Low-Mass X-ray Binary V801 Ara

Science.gov (United States)

Brauer, Kaley; Vrtilek, Saeqa Dil; Peris, Charith; McCollough, Michael

2018-06-01

We present phase-resolved optical spectra of the low mass X-ray binary system V801 Ara. The spectra, obtained in 2014 with IMACS on the Magellan/Baade telescope at Las Campanas Observatory, cover the full binary orbit of 3.8 hours. They contain strong emission features allowing us to map the emission of Hα, Hβ, He II λ4686, and the Bowen blend at λ4640. The radial velocity curves of the Bowen blend shows significantly stronger modulation at the orbital period than Hα as expected for the former originating on the secondary with the latter consistent with emission dominated by the disk. Our tomograms of Hα and Hβ are the most detailed studies of these lines for V801 to date and they clearly detect the accretion disk. The Hβ emission extends to higher velocities than Hα, suggesting emission from closer to the neutron star and differentiating temperature variance in the accretion disk for the first time. The center of the accretion disk appears offset from the center-of-mass of the neutron star as has been seen in several other X-ray binaries. This is often interpreted to imply disk eccentricity. Our tomograms do not show strong evidence for a hot spot at the point where the accretion stream hits the disk. This could imply a reduced accretion rate or could be due to the spot being drowned out by bright accretion flow around it. There is enhanced emission further along the disk, however, which implies gas stream interaction downstream of the hot spot.

Topology and Shape Control for Assemblies of Block Copolymer Blends in Solution

KAUST Repository

Moreno Chaparro, Nicolas; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor; Calo, Victor M.

2015-01-01

We study binary blends of asymmetric diblock copolymers (AB/AC) in selective solvents with a mesoscale model. We investigate the morphological transitions induced by the concentration of the AC block copolymer and the difference in molecular weight between the AB and AC copolymers, when segments B and C exhibit hydrogen-bonding interactions. To the best of our knowledge, this is the first work modeling mixtures of block copolymers with large differences in molecular weight. The coassembly mechanism localizes the AC molecules at the interface of A and B domains and induces the swelling of the B-rich domains. The coil size of the large molecular weight block copolymer depends only on the concentration of the short block copolymer (AC or AB), regardless of the B–C interactions. However, the B–C interactions control the morphological transitions that occur in these blends.

Topology and Shape Control for Assemblies of Block Copolymer Blends in Solution

KAUST Repository

Moreno Chaparro, Nicolas

2015-10-27

We study binary blends of asymmetric diblock copolymers (AB/AC) in selective solvents with a mesoscale model. We investigate the morphological transitions induced by the concentration of the AC block copolymer and the difference in molecular weight between the AB and AC copolymers, when segments B and C exhibit hydrogen-bonding interactions. To the best of our knowledge, this is the first work modeling mixtures of block copolymers with large differences in molecular weight. The coassembly mechanism localizes the AC molecules at the interface of A and B domains and induces the swelling of the B-rich domains. The coil size of the large molecular weight block copolymer depends only on the concentration of the short block copolymer (AC or AB), regardless of the B–C interactions. However, the B–C interactions control the morphological transitions that occur in these blends.

High throughput study of fuel cell proton exchange membranes: Poly(vinylidene fluoride)/acrylic polyelectrolyte blends and nanocomposites with zirconium

Science.gov (United States)

Zapata B., Pedro Jose

Sustainability is perhaps one of the most heard buzzwords in the post-20 th century society; nevertheless, it is not without a reason. Our present practices for energy supply are largely unsustainable if we consider their environmental and social impact. In view of this unfavorable panorama, alternative sustainable energy sources and conversion approaches have acquired noteworthy significance in recent years. Among these, proton exchange membrane fuel cells (PEMFCs) are being considered as a pivotal building block in the transition towards a sustainable energy economy in the 21st century. The polyelectrolyte membrane or proton exchange membrane (PEM) is a vital component, as well as a performance-limiting factor, of the PEMFC. Consequently, the development of high-performance PEM materials is of utmost importance for the advance of the PEMFC field. In this work, alternative PEM materials based on semi-interpenetrated networks from blends of poly(vinyledene fluoride) (PVDF) (inert phase) and sulfonated crosslinked acrylic polyelectrolytes (PE) (proton-conducting phase), as well as tri-phase PVDF/PE/zirconium-based composites, are studied. To alleviate the burden resulting from the vast number of possible combinations of the different precursors utilized in the preparation of the membranes (PVDF: 5x, PE: 2x, Nanoparticle: 3x), custom high-throughput (HT) screening systems have been developed for their characterization. By coupling the data spaces obtained via these systems with the appropriate statistical and data analysis tools it was found that, despite not being directly involved in the proton transport process, the inert PVDF phase plays a major role on proton conductivity. Particularly, a univocal inverse correlation between the PVDF crystalline characteristics (i.e., crystallinity and crystallite size) and melt viscosity, and membrane proton conductivity was discovered. Membranes based on highly crystalline and viscous PVDF homopolymers exhibited reduced proton

Membrane technology and applications

International Nuclear Information System (INIS)

Khalil, F.H.

1997-01-01

The main purpose of this dissertation is to prepare and characterize some synthetic membranes obtained by radiation-induced graft copolymerization of and A Am unitary and binary system onto nylon-6 films. The optimum conditions at which the grafting process proceeded homogeneously were determined. Some selected properties of the prepared membranes were studied. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), x-ray diffraction (XRD), mechanical properties and U.V./vis, instruments and techniques were used to characterize the prepared membranes. The use of such membranes for the decontamination of radioactive waste and some heavy metal ions as water pollutants were investigated. These grafted membranes showed good cation exchange properties and may be of practical interest in waste water treatment whether this water was radioactive or not. 4 tabs., 68 figs., 146 refs

PVA/Polysaccharides Blended Films: Mechanical Properties

OpenAIRE

Silva, Fábio E. F.; Di-Medeiros, Maria Carolina B.; Batista, Karla A.; Fernandes, Kátia F.

2013-01-01

Blends of polyvinyl alcohol (PVA) and angico gum (AG) and/or cashew gum (CG) were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO). The films presented thickness varying from 70 to 140 μm (PVA/AG) and 140 to 200 μm (PVA/CG). Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher valu...

Ice formation in model biological membranes in the presence of cryoprotectors

Energy Technology Data Exchange (ETDEWEB)

Kiselev, M.A. E-mail: kiselev@nf.jinr.ru; Lesieur, P.; Kisselev, A.M.; Ollivon, M

2000-06-21

Ice formation in model biological membranes is studied by SAXS and WAXS in the presence of cryoprotectors: dimethyl sulfoxide and glycerol. Three types of phospholipid membranes: DPPC, DMPC, DSPC are chosen for the investigation as well-studied model biological membranes. A special cryostat is used for sample cooling from 14.1 deg. C to -55.4 deg. C. The ice formation is detected only by WAXS in binary phospholipid/water and ternary phospholipid/cryoprotector/water systems in the condition of excess solvent. Ice formation in a binary phospholipid/water system creates an abrupt decrease of the membrane repeat distance by {delta}d, the so-called ice-induced dehydration of intermembrane space. The value of {delta}d decreases as the cryoprotector concentration increases. The formation of ice does not influence the membrane structure ({delta}d=0) for cryoprotector mole fractions higher than 0.05.

Modified SPEEK membranes for direct ethanol fuel cell

KAUST Repository

Maab, Husnul; Nunes, Suzana Pereira

2010-01-01

/PI homogeneous blends. The membranes were characterized concerning their water and ethanol solution uptake, water and ethanol permeability in pervaporation experiments and their performance in DEFC tests. The ethanol permeabilities for the CMS-coated (180 nm

Preparation of PVDF porous membranes by using PVDF-g-PVP powder as an additive and their antifouling property

International Nuclear Information System (INIS)

Xu, Chenqi; Huang, Wei; Lu, Xin; Yan, Deyue; Chen, Shutao; Huang, Hua

2012-01-01

The hydrophilic PVDF-g-PVP powder was used as additive to prepare a series of PVDF/PVDF-g-PVP blend porous membranes via an immersion precipitation phase inversion process. FTIR-ATR measurements confirmed that the hydrophilic PVP preferentially segregated to the interface between membrane and coagulant. SEM images showed that there was no big change in the membrane cross-section with the amount of PVDF-g-PVP increased. However, the membrane surface roughness increased with the amount of PVDF-g-PVP increased according to AFM data. The mean pore size of membranes reached max when the amount of PVDF-g-PVP was 10 wt%. The water contact angle and filtration experiments revealed that the surface enrichment of PVP endowed the membranes with significantly enhanced surface hydrophilicity and protein-adsorption resistance. The flux recovery of the porous membranes was increased from 37.50% to 77.23% with the amount of PVDF-g-PVP increased from 0 to 50 wt%, also indicating that the antifouling property of the porous membranes was improved. - Highlights: ► The hydrophilic PVDF-g-PVP powder is used as additive to prepare PVDF/PVDF-g-PVP blend porous membranes. ► The immersion precipitation phase inversion process is adopted to prepare the blend membranes. ► The hydrophilicity of the porous membranes surface is enhanced with increasing the amount of PVDF-g-PVP. ► The pure water flux of the porous membranes depends on the amount of PVDF-g-PVP in the porous membranes. ► Antifouling property of the porous membranes is improved obviously comparing with a pristine PVDF membrane.

The ‘ideal selectivity’ vs ‘true selectivity’ for permeation of gas mixture in nanoporous membranes

Science.gov (United States)

He, Zhou; Wang, Kean

2018-03-01

In this study, we proposed and validated a novel and non-destructive experimental technology for measuring the permeation of binary gas mixture in nanoporous membranes. The traditional time lag rig was modified to examine the permeation characteristics of each gas component as well as that of the binary gas mixtures. The difference in boiling points of each species were explored. Binary gas mixtures of CO2/He were permeated through the nanoporous carbon molecular sieve membrane (CMSM). The results showed that, due to the strong interaction among different molecules and with the porous network of the membrane, the measured perm-selectivity or ‘true selectivity’ of a binary mixture can significantly deviate from the ‘ideal selectivity’ calculated form the permeation flux of each pure species, and this deviation is a complicated function of the molecular properties and operation conditions.

Predicted bond length variation in wurtzite and zinc-blende InGaN and AlGaN alloys

International Nuclear Information System (INIS)

Mattila, T.; Zunger, A.

1999-01-01

Valence force field simulations utilizing large supercells are used to investigate the bond lengths in wurtzite and zinc-blende In x Ga 1-x N and Al x Ga 1-x N random alloys. We find that (i) while the first-neighbor cation endash anion shell is split into two distinct values in both wurtzite and zinc-blende alloys (R Ga-N 1 ≠R In-N 1 ), the second-neighbor cation endash anion bonds are equal (R Ga-N 2 =R In-N 2 ). (ii) The second-neighbor cation endash anion bonds exhibit a crucial difference between wurtzite and zinc-blende binary structures: in wurtzite we find two bond distances which differ in length by 13% while in the zinc-blende structure there is only one bond length. This splitting is preserved in the alloy, and acts as a fingerprint, distinguishing the wurtzite from the zinc-blende structure. (iii) The small splitting of the first-neighbor cation endash anion bonds in the wurtzite structure due to nonideal c/a ratio is preserved in the alloy, but is obscured by the bond length broadening. (iv) The cation endash cation bond lengths exhibit three distinct values in the alloy (Ga endash Ga, Ga endash In, and In endash In), while the anion endash anion bonds are split into two values corresponding to N endash Ga endash N and N endash In endash N. (v) The cation endash related splitting of the bonds and alloy broadening are considerably larger in InGaN alloy than in AlGaN alloy due to larger mismatch between the binary compounds. (vi) The calculated first-neighbor cation endash anion and cation endash cation bond lengths in In x Ga 1-x N alloy are in good agreement with the available experimental data. The remaining bond lengths are provided as predictions. In particular, the predicted splitting for the second-neighbor cation endash anion bonds in the wurtzite structure awaits experimental testing. copyright 1999 American Institute of Physics

Hydrogen production in membrane reactors using Rh catalysts on binary supports

Energy Technology Data Exchange (ETDEWEB)

Carrara, Carlos; Roa, Alejandro; Cornaglia, Laura; Lombardo, Eduardo A. [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Sgo del Estero 2829-3000 Santa Fe (Argentina); Mateos-Pedrero, Cecilia; Ruiz, Patricio [Unite de Catalyse et Chimie des Materiaux Divises, Universite Catholique de Louvain, Place Croix du Sud 2/17, 1348 Louvain-la Neuve (Belgium)

2008-04-15

The binary supports employed in this work were prepared by different methods. The Ti(7%)-MgO and the Ti(13%)-SiO{sub 2} were obtained using the grafting technique. The La(27%)-SiO{sub 2} was obtained through the incipient wetness impregnation with La(NO{sub 3}){sub 3} of Aerosil 300, previously calcined at 1173 K. The Rh was incorporated to these supports by wet impregnation. The catalysts were first evaluated for the CH{sub 4} + CO{sub 2} reaction in a fixed-bed reactor. They were found to be active and stable as to justify their use in the membrane reactor, which was operated at 823 K achieving methane conversions up to twice as much as the equilibrium values. In all cases, the activity of the Rh solids remained constant after 120 h on stream with very little formation of carbonaceous residues only detected through LRS. The catalysts were characterized through either hydrogen or carbon monoxide chemisorption, TPR, XRD, LRS and XPS. The Rh(0.6)/La-SiO{sub 2} catalyst showed a high metal dispersion that remained constant after use and the highest capacity to restore the CH{sub 4} + CO{sub 2} equilibrium when H{sub 2} was permeated out of the reaction section. The Rh(0.8)/Ti-MgO showed the highest Rh/oxide interaction associated with the lowest capacity to restore the reaction equilibrium. The Rh(0.8)/Ti-SiO{sub 2} exhibited an intermediate activity due in part to the partial segregation of the TiO{sub 2} upon calcinations and the subsequent appearance of small Rh crystallites in the used catalysts. (author)

Study of component distribution in pharmaceutical binary powder mixtures by near infrared chemical imaging

Directory of Open Access Journals (Sweden)

Manel Bautista

2012-12-01

Full Text Available Near infrared chemical imaging (NIR-CI has recently emerged as an effective technique for extracting spatial information from pharmaceutical products in an expeditious, non-destructive and non-invasive manner. These features have turned it into a useful tool for controlling various steps in drug production processes. Imaging techniques provide a vast amount of both spatial and spectral information that can be acquired in a very short time. Such a huge amount of data requires the use of efficient and fast methods to extract the relevant information. Chemometric methods have proved especially useful for this purpose. In this study, we assessed the usefulness of the correlation coefficient (CC between the spectra of samples, the pure spectra of the active pharmaceutical ingredient (API and we assessed the excipients to check for correct ingredient distribution in pharmaceutical binary preparations blended in the laboratory. Visual information about pharmaceutical component distribution can be obtained by using the CC. The performance of this model construction methodology for binary samples was compared with other various common multivariate methods including partial least squares, multivariate curve resolution and classical least squares. Based on the results, correlation coefficients are a powerful tool for the rapid assessment of correct component distribution and for quantitative analysis of pharmaceutical binary formulations. For samples of three or more components it has been shown that if the objective is only to determine uniformity of blending, then the CC image map is very good for this, and easy and fast to compute.

Effect of diamond blend on the gas-separation properties of composite membranes

Science.gov (United States)

Kryuchkova, S. V.; Kostina, Yu. V.; Yablokova, M. Yu.; Gasanova, L. G.; Kepman, A. V.

2017-10-01

The morphological structure and gas transport properties of polyimide- and polyamide-imidebased rigid-chain polymers containing a fine carbon filler (a diamond blend) are studied. Gas transport properties are measured, and the effect exerted on these properties by intermolecular interaction between the functional groups of polymer chains and the fine filler is analyzed.

Production and characterization of thermoplastic cassava starch, functionalized poly(lactic acid), and their reactive compatibilized blends

Science.gov (United States)

Detyothin, Sukeewan

degree of grafted MA, and increasing MA content retarded the reduction of Mn during processing. However, the Mn of PLA-g-MA during storage decreased more rapidly with a high content of MA. TSE screw speed had an impact on the Mn with the maximum value predicted at 20 rpm. PLA-g-MA compounds differing in Mn and/or grafted MA content were used as reactive polymers with TPCS (to produce binary blends) and as reactive compatibilizers (to produce ternary blends of PLA/TPCS/PLA-g-MA) with TPCS content of 30 wt% using a TSE. As a result of maleation, PLA-g-MA had a higher grafted MA content with a lower Mn, and higher PI. The interaction of anhydride groups from PLA-g-MA and hydroxyl groups from TPCS was found by FTIR. The reactive binary blends exhibited a change in thermal stability, decrease of Tcc, the presence of double melting peaks, and an increase of the Tgs of glycerol and starch. The higher the grafted MA content and/or the higher Mn of the PLA- g-MA used, the better were the distribution and smaller the TPCS domains obtained in the blends. The highest elongation at break was achieved when 30 wt% TPCS was blended with 70 wt% of PLA having 0.1 wt% of grafted MA and Mn of PLA-g-MA with a 45 kDa. Finally, the optimum PLA-g-MA was determined by using the results from PLA-g-MA RSM design and the reactive blending.

CONSOLIDATION AND COMPACTION OF POWDER MIXTURES .3. BINARY-MIXTURES OF DIFFERENT PARTICLE-SIZE FRACTIONS OF DIFFERENT TYPES OF CRYSTALLINE LACTOSE

NARCIS (Netherlands)

RIEPMA, KA; ZUURMAN, K; BOLHUIS, GK; DEBOER, AH; LERK, CF

1992-01-01

Tablets were compacted from a coarse fraction (250-315 mum), a fine fraction (32-45 mum) and from binary blends of a coarse and a fine fraction of different types of crystalline lactose. The results showed differences in consolidation and compaction between the granular lactose types, i.e.,

Polybenzimidazole/Mxene composite membranes for intermediate temperature polymer electrolyte membrane fuel cells

Science.gov (United States)

Fei, Mingming; Lin, Ruizhi; Deng, Yuming; Xian, Hongxi; Bian, Renji; Zhang, Xiaole; Cheng, Jigui; Xu, Chenxi; Cai, Dongyu

2018-01-01

This report demonstrated the first study on the use of a new 2D nanomaterial (Mxene) for enhancing membrane performance of intermediate temperature (>100 °C) polymer electrolyte membrane fuel cells (ITPEMFCs). In this study, a typical Ti3C2T x -MXene was synthesized and incorporated into polybenzimidazole (PBI)-based membranes by using a solution blending method. The composite membrane with 3 wt% Ti3C2T x -MXene showed the proton conductivity more than 2 times higher than that of pristine PBI membrane at the temperature range of 100 °C-170 °C, and led to substantial increase in maximum power density of fuel cells by ˜30% tested at 150 °C. The addition of Ti3C2T x -MXene also improved the mechanical properties and thermal stability of PBI membranes. At 3 wt% Ti3C2T x -MXene, the elongation at break of phosphoric acid doped PBI remained unaffected at 150 °C, and the tensile strength and Young’s modulus was increased by ˜150% and ˜160%, respectively. This study pointed out promising application of MXene in ITPEMFCs.

Blended learning

DEFF Research Database (Denmark)

Dau, Susanne

2016-01-01

Blended Learning has been implemented, evaluated and researched for the last decades within different educational areas and levels. Blended learning has been coupled with different epistemological understandings and learning theories, but the fundamental character and dimensions of learning...... in blended learning are still insufficient. Moreover, blended learning is a misleading concept described as learning, despite the fact that it fundamentally is an instructional and didactic approach (Oliver & Trigwell, 2005) addressing the learning environment (Inglis, Palipoana, Trenhom & Ward, 2011......) instead of the learning processes behind. Much of the existing research within the field seems to miss this perspective. The consequence is a lack of acknowledgement of the driven forces behind the context and the instructional design limiting the knowledge foundation of learning in blended learning. Thus...

Morphology in binary blends of poly(vinyl methyl ether) and epsilon-caprolactone-trimethylene carbonate diblock copolymer

NARCIS (Netherlands)

Luyten, MC; Bogels, EJF; vanEkenstein, GORA; tenBrinke, G; Bras, W; Komanschek, BE; Ryan, AJ

The morphology of symmetric diblock copolymer of epsilon-caprolactone (PCL) and trimethylene carbonate (PTMC), in blends with poly(vinyl methyl ether) (PVME) is investigated with (modulated) differential scanning calorimetry (d.s.c.), time resolved small angle (SAXS) and wide angle (WAXS) X-ray

Morphology in binary blends of poly(vinyl methyl ether) and ε-caprolactone-trimethylene carbonate diblock copolymer

NARCIS (Netherlands)

Luyten, M.C.; Bögels, E.J.F.; Alberda van Ekenstein, G.O.R.; Brinke, G. ten; Bras, W.; Komanschek, B.E.; Ryan, A.J.

1997-01-01

The morphology of symmetric diblock copolymer of ε-caprolactone (PCL) and trimethylene carbonate (PTMC), in blends with poly(vinyl methyl ether) (PVME) is investigated with (modulated) differential scanning calorimetry (d.s.c.), time resolved small angle (SAXS) and wide angle (WAXS) X-ray

Progress in surface and membrane science

CERN Document Server

Cadenhead, D A

1981-01-01

Progress in Surface and Membrane Science, Volume 14 covers the advances in the study of surface and membrane science. The book discusses statistical thermodynamics of monolayer adsorption from gas and liquid mixtures on homogeneous and heterogeneous solid surfaces; and the structure of the boundary layers of liquids and its influence on the mass transfer in fine pores. The text then describes the coupling of ionic and non-electrolyte fluxes in ion selective membranes; the electrocatalytic properties of matalloporphins at the interface; and the adsorption from binary gas and liquid phases. Phas

Sulfonation and characterization of styrene-indene copolymers for the development of proton conducting polymer membranes

Directory of Open Access Journals (Sweden)

Cristiane M. Becker

2012-01-01

Full Text Available The aim of this work is to obtain polymer precursors based on styrene copolymers with distinct degrees of sulfonation, as an alternative material for fuel cell membranes. Acetyl sulfate was used to carry out the sulfonation and the performance of the polyelectrolyte was evaluated based on the content of acid polar groups incorporated into the macromolecular chain. Polymeric films were produced by blending the sulfonated styrene-indene copolymer with poly(vinylidene fluoride. The degree of sulfonation of the polymer was strongly affected by the sulfonation reaction parameters, with a direct impact on the ionic exchange capacity and the ionic conductivity of the sulfonated polymers and the membranes obtained from them. The films produced with the blends showed more suitable mechanical properties, although the conductivity of the membranes was still lower than that of commercially available membranes used in fuel cells.

Reverse indentation size effects in gamma irradiated blood compatible blend films of chitosan-poly (vinyl alcohol) for possible medical applications

Energy Technology Data Exchange (ETDEWEB)

Bisen, D.S. [Department of Post Graduate Studies and Research in Physics, Rani Durgawati University, Jabalpur, M.P. 482002 (India); Bhatt, Rinkesh [Department of Physics, Global Engineering College, Jabalpur, M.P. 482001 (India); Bajpai, A.K., E-mail: akbmrl@yahoo.co.in [Department of Chemistry, Bose Memorial Research Lab., Govt. Auto. Model Science College, Jabalpur 482002, M.P. (India); Bajpai, R. [Department of Post Graduate Studies and Research in Physics, Rani Durgawati University, Jabalpur, M.P. 482002 (India); Katare, R. [Department of Physics, Government Model Science College, Jabalpur, M.P. 482001 (India)

2017-02-01

In the present work binary blends of polyvinyl alcohol (PVA) and chitosan (CS) were prepared by solution cast method and characterized by analytical methods like FTIR, XRD and SEM for seeking structural and morphological information. The blends were exposed to gamma radiation and evaluated for their improved mechanical strength. It was found that the tensile strength and microhardness increased after irradiation of CS-PVA films. Plastic effect due to absorption of water molecules and scissoring effect due to gamma irradiation were found to decrease the softness or increase the microhardness of the blends. Improved mechanical properties were attributed to intermolecular and intramolecular hydrogen bonds and adhesive nature of the blends also. The blends were also investigated for water intake behavior and in vitro blood compatibility property on the basis of certain in vitro tests like protein adsorption, haemolysis and blood clot formation on the un-irradiated and irradiated blend samples. The increased % swelling with time could be assigned to the fact that increasing water content facilitates the phase separation process within the blend which results in advancement in interstitial nano-void spaces which are occupied by water molecules. The blood compatibility results showed that when the amount of CS was varied from 0.5% to 2%, the amount of blood clot and percent haemolysis decreased while the protein adsorption increased with increasing CS content of the blend films. - Highlights: • Fully crosslinked blends of PVA and chitosan have been prepared. • Blends were irradiated with gamma radiations to enhance blood compatibility. • Mechanical properties were evaluated and effect of irradiation was examined. • The blood compatibility of blends was also determined.

Reverse indentation size effects in gamma irradiated blood compatible blend films of chitosan-poly (vinyl alcohol) for possible medical applications

International Nuclear Information System (INIS)

Bisen, D.S.; Bhatt, Rinkesh; Bajpai, A.K.; Bajpai, R.; Katare, R.

2017-01-01

In the present work binary blends of polyvinyl alcohol (PVA) and chitosan (CS) were prepared by solution cast method and characterized by analytical methods like FTIR, XRD and SEM for seeking structural and morphological information. The blends were exposed to gamma radiation and evaluated for their improved mechanical strength. It was found that the tensile strength and microhardness increased after irradiation of CS-PVA films. Plastic effect due to absorption of water molecules and scissoring effect due to gamma irradiation were found to decrease the softness or increase the microhardness of the blends. Improved mechanical properties were attributed to intermolecular and intramolecular hydrogen bonds and adhesive nature of the blends also. The blends were also investigated for water intake behavior and in vitro blood compatibility property on the basis of certain in vitro tests like protein adsorption, haemolysis and blood clot formation on the un-irradiated and irradiated blend samples. The increased % swelling with time could be assigned to the fact that increasing water content facilitates the phase separation process within the blend which results in advancement in interstitial nano-void spaces which are occupied by water molecules. The blood compatibility results showed that when the amount of CS was varied from 0.5% to 2%, the amount of blood clot and percent haemolysis decreased while the protein adsorption increased with increasing CS content of the blend films. - Highlights: • Fully crosslinked blends of PVA and chitosan have been prepared. • Blends were irradiated with gamma radiations to enhance blood compatibility. • Mechanical properties were evaluated and effect of irradiation was examined. • The blood compatibility of blends was also determined.

Performance, emission and combustion analysis of a compression ignition engine using biofuel blends

Directory of Open Access Journals (Sweden)

Ors Ilker

2017-01-01

Full Text Available This study aimed to investigate the effects on performance, emission, and combustion characteristics of adding biodiesel and bioethanol to diesel fuel. Diesel fuel and blend fuels were tested in a water-cooled compression ignition engine with direct injection. Test results showed that brake specific fuel consumption and volumetric efficiency increased by about 30.6% and 3.7%, respectively, with the addition of bioethanol to binary blend fuels. The results of the blend fuel’s combustion analysis were similar to the diesel fuel’s results. Bioethanol increased maximal in-cylinder pressure compared to biodiesel and diesel fuel at both 1400 rpm and 2800 rpm. Emissions of CO increased by an amount of about 80% for fuels containing a high level of bioethanol when compared to CO emissions for diesel fuel. Using biodiesel, NO emissions increased by an average of 31.3%, HC emissions decreased by an average of 39.25%, and smoke opacity decreased by an average of 6.5% when compared with diesel fuel. In addition, when using bioethanol, NO emissions and smoke opacity decreased by 55% and 17% on average, respectively, and HC emissions increased by an average of 53% compared with diesel fuel.

Supporting School Leaders in Blended Learning with Blended Learning

Science.gov (United States)

Acree, Lauren; Gibson, Theresa; Mangum, Nancy; Wolf, Mary Ann; Kellogg, Shaun; Branon, Suzanne

2017-01-01

This study provides a mixed-methods case-study design evaluation of the Leadership in Blended Learning (LBL) program. The LBL program uses blended approaches, including face-to-face and online, to prepare school leaders to implement blended learning initiatives in their schools. This evaluation found that the program designers effectively…

A Structural Study of the Pseudo-Binary Mercury Chalcogenide Alloy HgSe_{0.7}S_{0.3} at High Pressure

CERN Document Server

Kozlenko, D P; Ehm, L; Knorr, K; Hull, S; Shchennikov, V V; Voronin, V I

2002-01-01

The structure of the pseudo-binary mercury chalcogenide alloy HgSe_{0.7}S_{0.3} has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P{\\sim}1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of Landau theory of the phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e_{4}. This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides.

A structural study of the pseudo-binary mercury chalcogenide alloy HgSe0.7S0.3 at high pressure

International Nuclear Information System (INIS)

Kozlenko, D.P.; Savenko, B.N.; Ehm, L.; Knorr, K.; Hull, S.; Shchennikov, V.V.; Voronin, V.I.

2002-01-01

The structure of the pseudo-binary mercury chalcogenide alloy HgSe 0.7 S 0.3 has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P∼1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of the Landau theory of phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e 4 . This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides

Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

KAUST Repository

Pan, Yichang

2012-02-01

The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed excellent separation performances for a wide range of propylene/propane mixtures. The membrane showed a permeability of propylene up to 200. barrers and a propylene to propane separation factor up to 50 at optimal separation conditions, well surpassing the "upper-bound trade-off" lines of existing polymer and carbon membranes. The experimental data also showed that the membranes had excellent reproducibility, long-term stability and thermal stability. © 2011 Elsevier B.V.

Blended Learning

OpenAIRE

Bauerová, Andrea

2013-01-01

This thesis is focused on a new approach of education called blended learning. The history and developement of Blended Learning is described in the first part. Then the methods and tools of Blended Learning are evaluated and compared to the traditional methods of education. At the final part an efficient developement of the educational programs is emphasized.

Rheological, mechanical and morphological properties of poly(methyl methacrylate/poly(ethylene terephthalate blend with dual reactive interfacial compatibilization

Directory of Open Access Journals (Sweden)

Juciklécia da Silva Reinaldo

2015-10-01

Full Text Available Abstract In this work, the rheological, mechanical and morphological behavior of immiscible blend poly (methyl methacrylate with elastomeric particles (PMMAelast and post-consumer poly (ethylene terephthalate (PET with and without the use of the interfacial compatibilizer poly (methyl methacrylate-co-glycidyl methacrylate-co-ethyl acrylate (MGE was studied. The significant increase in torque presented in rheological analyses has shown a indication of chemical reactions between the epoxy group of MGE with end groups of PET chains and also with the elastomeric phase of PMMAelast. The increased concentration of PET yielded an increase in maximum strength and elasticity modulus and a decrease in elongation at break. The PMMAelast/PET binary blend (50/50 wt% and PMMAelast/PET/MGE compatibilized blend (65/30/5 wt% showed pronounced results in elongation at break compared to PMMAelast, whereas, in the first results were due to the evidence of a co-continuous morphological structure and in the second, due to the efficiency of the dual reactive interfacial compatibilization of PMMAelast/PET blends. Scanning electron microscopy (SEM and transmission electron microscopy (TEM analyses showed that PMMAelast/PET/MGE blends exhibit complex phase morphology due to the presence of elastomeric particles in the PMMAelast copolymer and in the use of MGE terpolymer.

Highly conductive thermoplastic composite blends suitable for injection molding of bipolar plates

International Nuclear Information System (INIS)

Mighri, F.; Huneault, M.A.; Champagne, M.F.

2003-01-01

This study aimed at developing highly conductive, lightweight, and low-cost bipolar plates for use in proton exchange membranes (PEM) fuel cells. Injection and compression molding of highly filled polypropylene, PP, and polyphenylene sulfide, PPS, based blends were used as a mean for mass production of bipolar plates. Loadings up to 60-wt% in the form of graphite, conductive carbon black and carbon fibers were investigated. The developed formulations have a combination of properties and processability suitable for bipolar plate manufacturing, such as good chemical resistance, sufficient fluidity, and good electrical and thermal conductivity. Electrical resistivities around 0.15 and 0.09 Ohm-cm were respectively achieved for the PP and PPS-based blends, respectively. Two bipolar plate designs were successfully fabricated by molding the gas flow channels over aluminum plates to form a metallic/polymer composite plate, or simply by direct injection molding of the conductive polymer composite. For the first design, overall plate resistivities of 0.2 and 0.1 Ohm-cm were respectively attained using PP and PPS based blends as conductive skin. A lower volume resistivity of around 0.06 Ohm-cm was attained for the second injected plate design with PPS based blend. (author)

Hemocompatible polyethersulfone/polyurethane composite membrane for high-performance antifouling and antithrombotic dialyzer.

Science.gov (United States)

Yin, Zehua; Cheng, Chong; Qin, Hui; Nie, Chuanxiong; He, Chao; Zhao, Changsheng

2015-01-01

Researches on blood purification membranes are fuelled by diverse clinical needs, such as hemodialysis, hemodiafiltration, hemofiltration, plasmapheresis, and plasma collection. To approach high-performance dialyzer, the integrated antifouling and antithrombotic properties are highly necessary for the design/modification of advanced artificial membranes. In this study, we propose and demonstrate that the physical blend of triblock polyurethane (PU) and polyethersulfone (PES) may advance the performance of hemodialysis membranes with greatly enhanced blood compatibility. It was found that the triblock PU could be blended with PES at high ratio owing to their excellent miscibility. The surfaces of the PES/PU composite membranes were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurement, and surface ζ-potentials. The results indicated that the membrane surfaces were assembled with hydrophilic segregation layer owing to the migration of amphiphilic PU segments during membrane preparation, which might confer the composite membranes with superior hemocompatibility. The cross-section scanning electron microscopy images of the composite membranes exhibited structure transformation from finger-like structure to sponge-like structure, which indicated that the composite membrane had tunable porosity and permeability. The further ultrafiltration experiments indicated that the composite membranes showed increased permeability and excellent antifouling ability. The blood compatibility observation indicated that PES/PU composite membranes owned decreased protein adsorption, suppressed platelet adhesion, and prolonged plasma recalcification time. These results indicated that the PES/PU composite membranes exhibited enhanced antifouling and antithrombotic properties than the pristine PES membrane. The strategy may forward the fabrication of blood compatible composite membranes for

Fundamental characteristics study of anion-exchange PVDF-SiO(2) membranes.

Science.gov (United States)

Zuo, Xingtao; Shi, Wenxin; Yu, Shuili; He, Jiajie

2012-01-01

A new type of poly(vinylidene fluoride)(PVDF)-SiO(2) hybrid anion-exchange membrane was prepared by blending method. The anion-exchange groups were introduced by the reaction of epoxy groups with trimethylamine (TMA). Contact angle between water and the membrane surface was measured to characterize the hydrophilicity change of the membrane surface. The effects of nano-sized SiO(2) particles in the membrane-forming materials on the membrane mechanical properties and conductivity were also investigated. The experimental results indicated that PVDF-SiO(2) anion-exchange membranes exhibited better water content, ion-exchange capacity, conductivity and mechanic properties, and so may find potential applications in alkaline membrane fuel cells and water treatment processes.

KARAKTERISTIK INTERAKSI MEMBRAN-FOULANT DAN FOULANT-FOULANT SEBAGAI DASAR PENGENDALIAN FOULING

Directory of Open Access Journals (Sweden)

Heru Susanto

2012-05-01

Full Text Available THE CHARACTERISTICS OF MEMBRANE-FOULANT AND FOULANT-FOULANT INTERACTIONS AS THE BASIS FOR CONTROL OF FOULING. Industrial membrane applications for solid liquid and liquid-liquid filtration are limited by fouling and concentration polarization. Because fouling significantly reduces the membrane performance and often changes the membrane selectivity, efforts to overcome the fouling problem are very important from practical applications point of view. This paper presents the basic knowledge required to control fouling and recent development in fouling control including the method developed by the author. Control of fouling can be done by (i commercial membrane modification (post modification by photo-graft polymerization, (ii modification by polymer blending during membrane manufacturing and (iii integration of a pretreatment into membrane processes. The results showed that all the developed methods can significantly reduce the resulting fouling; however, none of the method could totally remove the occurring fouling. The understanding of the membrane-foulant and foulant-foulant interactions is the key to success in control of fouling.Aplikasi teknologi membran untuk pemisahan padat cair di  berbagai industri dibatasi oleh peristiwa fouling yang menyebabkan penurunan laju produk dan perubahan selektifitas membran. Oleh karena itu, pengendalian fouling merupakan upaya yang mutlak harus dilakukan. Makalah ini mempresentasikan pengetahuan dasar yang diperlukan untuk pengendalian fouling dan perkembangan terkini dalam pengendalian fouling termasuk hasil-hasil yang telah dikembangkan oleh penulis. Pengendalian fouling dilakukan dengan (i modifikasi membran komersial (post modification menggunakan metode photo-grafting, (ii modifikasi dengan pencampuran polimer selama proses pembuatan (polymer blend dan (iii integrasi unit perlakuan awal (pre-treatment dengan proses membran. Hasil penelitian menunjukkan bahwa kesemua metode yang dikembangkan dapat

Nonlinear Effects in Osmotic Volume Flows of Electrolyte Solutions through Double-Membrane System

NARCIS (Netherlands)

Slezak, A.; Jasik-Slezak, J.; Grzegorczyn, S.; Slezak-Prochazka, I.

The results of experimental study of volume osmotic flows in a double-membrane system are presented in this article. The double-membrane system consists of two membranes (M-u, M-d) oriented in horizontal planes and three identical compartments (u, m, d), containing unstirred binary or ternary ionic

Misturas binárias e ternárias de gorduras hidrogenadas e óleo de soja Binary and ternary blends of hydrogenated fats and soybean oil

Directory of Open Access Journals (Sweden)

Ilka Sumiyoshi SIMÕES

1997-12-01

interactions. Compared with traditional techniques, designed experimentation saves both time and resources, and identify "true"optimums. The designed strategy allows determination of effects of individual variables or interactions between them. The objective of this study was to investigate the interactions that occur in binary and ternary mixtures of two hydrogenated fats (FATGILL PF38 and FATGILL PF42 and soybean oil, by analyzing their physical and chemical properties. A ten-run designed was used, corresponding to 3 individual samples, 3 binary blends and 4 ternary blends. The samples were analysed for fatty acid composition, iodine and saponification values, softening and melting points, kinematic viscosity, hardness and consistency. A special cubic multiple regression model was applied to some analytical data. The results showed that the three components interactions were not significative. Hardness only depended on hydrogenated fat FATGILL PF42. In another way, viscosity was dependent on the three components and melting and softening points were dependent on hydrogenated fats. The negative coefficients for hardness showed an antagonic effect, typical of eutectic interactions of fats. Contour lines were indicated by triangular diagrams. A perfect mixing model was attested for viscosity and softening and melting points.

Evaluation of combustion, performance, and emissions of optimum palm–coconut blend in turbocharged and non-turbocharged conditions of a diesel engine

International Nuclear Information System (INIS)

Arbab, M.I.; Varman, M.; Masjuki, H.H.; Kalam, M.A.; Imtenan, S.; Sajjad, H.; Rizwanul Fattah, I.M.

2015-01-01

Highlights: • Properties limitation of biodiesel has been overcome using multiple biodiesel blends. • New biodiesel was developed using biodiesel–biodiesel optimum blend. • Engine performance and emission was tested with the newly developed biodiesels. • New biodiesels showed better engine performance than other tested fuels. - Abstract: Fossil fuel depletion, global warming with rapid changes in climate, and increases in oil prices have motivated scientists to search for alternative fuel. Biodiesel can be an effective solution despite some limitations, such as poor fuel properties and engine performance. From this perspective, experiments were carried out to improve fuel properties and engine performance by using a binary blend of palm and coconut biodiesel at an optimized ratio. MATLAB optimization tool was used to determine this blend ratio. A new biodiesel was developed and represented by PC (optimum blend of palm and coconut biodiesel). Engine performance and emission were tested under a full load at variable speed condition by using a 20% blend of each biodiesel with petroleum diesel, and the results were compared with petroleum diesel under both turbocharged and non-turbocharged conditions. PC20 (blend of 20% PC biodiesel and 80% petroleum diesel) showed the highest engine power with lower brake-specific fuel consumption than the other tested fuels in the presence of a turbocharger. The emissions of PC20 were lower than those of all other tested fuels. The experimental analysis reveals that PC showed superior performance and emission over palm biodiesel blend

Poly(ethylene glycol) and poly(dimethyl siloxane): Combining their advantages into efficient CO2 gas separation membranes

NARCIS (Netherlands)

Reijerkerk, Sander; Knoef, Michel H.; Nijmeijer, Dorothea C.; Wessling, Matthias

2010-01-01

Polymer blending is a versatile tool to combine the beneficial properties of two or more components in one single material. Here, we present the preparation, thermal- and mass transport properties of a series of blend membranes made from the commercially available PEBAX® MH 1657 and a poly(ethylene

Unmasking the hidden NGTS-3Ab: a hot Jupiter in an unresolved binary system

Science.gov (United States)

Günther, Maximilian N.; Queloz, Didier; Gillen, Edward; Delrez, Laetitia; Bouchy, François; McCormac, James; Smalley, Barry; Almleaky, Yaseen; Armstrong, David J.; Bayliss, Daniel; Burdanov, Artem; Burleigh, Matthew; Cabrera, Juan; Casewell, Sarah L.; Cooke, Benjamin F.; Csizmadia, Szilárd; Ducrot, Elsa; Eigmüller, Philipp; Erikson, Anders; Gänsicke, Boris T.; Gibson, Neale P.; Gillon, Michaël; Goad, Michael R.; Jehin, Emmanuël; Jenkins, James S.; Louden, Tom; Moyano, Maximiliano; Murray, Catriona; Pollacco, Don; Poppenhaeger, Katja; Rauer, Heike; Raynard, Liam; Smith, Alexis M. S.; Sohy, Sandrine; Thompson, Samantha J.; Udry, Stéphane; Watson, Christopher A.; West, Richard G.; Wheatley, Peter J.

2018-05-01

We present the discovery of NGTS-3Ab, a hot Jupiter found transiting the primary star of an unresolved binary system. We develop a joint analysis of multi-colour photometry, centroids, radial velocity (RV) cross-correlation function (CCF) profiles and their bisector inverse slopes (BIS) to disentangle this three-body system. Data from the Next Generation Transit Survey (NGTS), SPECULOOS and HARPS are analysed and modelled with our new BLENDFITTER software. We find that the binary consists of NGTS-3A (G6V-dwarf) and NGTS-3B (K1V-dwarf) at 5") and are prone to contamination by blended objects. With TESS on the horizon, it is pivotal for the candidate vetting to incorporate all available follow-up information from multi-colour photometry and RV CCF profiles.

Relations between blended learning possibilities and teachers' approaches to blended learning

DEFF Research Database (Denmark)

Stenalt, Maria Hvid; Nielsen, Tobias Alsted; Bager-Elsborg, Anna

Higher Education has embraced blended learning as a way of enhancing quality in teaching and helping students to learn. This presentation addresses relations between blended learning possiblities presented to teachers in a teacher training project and teachers’ approaches to blended learning. We...... suggest that in order to identify the level of impact of integrating technologies in teaching and learning, we need to understand the factors influencing approaches to design of courses for blended contexts. Participants in the teacher training project come from the Department of Law at Aarhus University......: • Optain locally-embedded knowledge about blended learning • Develop opportunities for law students to receive (more) feedback • Comply with strategic aims The results so far suggest that teachers provide a disciplinary perspective on the key dimensions of blended learning, which influences...

Controlling the porosity of a polyethersulfone membrane surface with an XeCl laser

International Nuclear Information System (INIS)

Pazokian, Hedieh; Mehrabadi, Adeleh H P; Mollabashi, Mahmoud; Barzin, Jalal

2016-01-01

Pure and polyvinyl pyrrolidone blend polyethersulfone (PES) membranes were irradiated by an XeCl laser with various numbers of pulses at different fluences to investigate the changes in the surface morphology and the porosity. The results show that the membrane pore size and distribution on the surface can be modified following irradiation dependent on the laser fluence, the number of pulses and the membrane composition. These changes are very attractive for improving the membrane surface in filtration processes and biological applications. (paper)

Effects of thermal efficiency in DCMD and the preparation of membranes with low thermal conductivity

Energy Technology Data Exchange (ETDEWEB)

Li, Zhehao, E-mail: ccgri_lzh@163.com [Changchun Gold Research Institute, 130012 (China); Peng, Yuelian, E-mail: pyl@live.com.au [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Dong, Yajun; Fan, Hongwei [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Chen, Ping [The Research Institute of Environmental Protection, North China Pharmaceutical Group Corporation, 050015 (China); Qiu, Lin [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Jiang, Qi [National Major Science and Technology Program Management Office for Water Pollution Control and Treatment, MEP, 100029 (China)

2014-10-30

Highlights: • The effects on vapor flux and thermal efficiency were simulated. • The conditions favoring vapor flux also favored thermal efficiency. • Four microporous polymer membranes were compared. • The SiO{sub 2} aerogel coating reduced the thermal conductivity of polymer membranes. • A 3ω technique was used to measure the thermal conductivity of membranes. - Abstract: The effects of the membrane characteristics and operational conditions on the vapor flux and thermal efficiency in a direct contact membrane distillation (DCMD) process were studied with a mathematical simulation. The membrane temperature, driving force of vapor transfer, membrane distillation coefficient, etc. were used to analyze the effects. The operating conditions that increased the vapor flux improved the thermal efficiency. The membrane characteristics of four microporous membranes and their performances in DCMD were compared. A polysulfone (PSf) membrane prepared via vapor-induced phase separation exhibited the lowest thermal conductivity. The PSf and polyvinylidene difluoride (PVDF) membranes were modified using SiO{sub 2} aerogel blending and coating to reduce the thermal conductivity of the membrane. The coating process was more effective than the blending process toward this end. The changes in the structure of the modified membrane were observed with a scanning electron microscope. Si was found on the modified membrane surface with an energy spectrometer. The PVDF composite and support membranes were tested during the DCMD process; the composite membrane had a higher vapor flux and a better thermal efficiency than the support. A new method based on a 3ω technique was used to measure the thermal conductivity of the membranes.

Effects of thermal efficiency in DCMD and the preparation of membranes with low thermal conductivity

International Nuclear Information System (INIS)

Li, Zhehao; Peng, Yuelian; Dong, Yajun; Fan, Hongwei; Chen, Ping; Qiu, Lin; Jiang, Qi

2014-01-01

Highlights: • The effects on vapor flux and thermal efficiency were simulated. • The conditions favoring vapor flux also favored thermal efficiency. • Four microporous polymer membranes were compared. • The SiO 2 aerogel coating reduced the thermal conductivity of polymer membranes. • A 3ω technique was used to measure the thermal conductivity of membranes. - Abstract: The effects of the membrane characteristics and operational conditions on the vapor flux and thermal efficiency in a direct contact membrane distillation (DCMD) process were studied with a mathematical simulation. The membrane temperature, driving force of vapor transfer, membrane distillation coefficient, etc. were used to analyze the effects. The operating conditions that increased the vapor flux improved the thermal efficiency. The membrane characteristics of four microporous membranes and their performances in DCMD were compared. A polysulfone (PSf) membrane prepared via vapor-induced phase separation exhibited the lowest thermal conductivity. The PSf and polyvinylidene difluoride (PVDF) membranes were modified using SiO 2 aerogel blending and coating to reduce the thermal conductivity of the membrane. The coating process was more effective than the blending process toward this end. The changes in the structure of the modified membrane were observed with a scanning electron microscope. Si was found on the modified membrane surface with an energy spectrometer. The PVDF composite and support membranes were tested during the DCMD process; the composite membrane had a higher vapor flux and a better thermal efficiency than the support. A new method based on a 3ω technique was used to measure the thermal conductivity of the membranes

Radiation grafting of styrene and maleic anhydride onto PTFE membranes and sequent sulfonation for applications of vanadium redox battery

International Nuclear Information System (INIS)

Qiu Jingyi; Ni Jiangfeng; Zhai Maolin; Peng Jing; Zhou Henghui; Li Jiuqiang; Wei Genshuan

2007-01-01

Using γ-radiation technique, poly(tetrafluoroethylene) (PTFE) membrane was grafted with styrene (St) (PTFE-graft-PS) or binary monomers of St and maleic anhydride (MAn) (PTFE-graft-PS-co-PMAn), respectively. Then grafted membranes were further sulfonated with chlorosulfonic acid into ion-exchange membranes (denoted as PTFE-graft-PSSA and PTFE-graft-PSSA-co-PMAc, respectively) for application of vanadium redox battery (VRB). Micro-FTIR analysis indicated that PTFE was successfully grafted and sulfonated at the above two different conditions. However, a higher degree of grafting (DOG) was obtained in St/MAn binary system at the same dose due to a synergistic effect. Comparing with PTFE-graft-PSSA, PTFE-graft-PSSA-co-PMAc membrane showed higher water uptake and ion-exchange capacity (IEC) and lower area resistance (AR) at the same DOG. In addition, PTFE-graft-PSSA-co-PMAc with 6% DOG also showed a higher IEC and higher conductivity compared to Nafion membrane. Radiation grafting of PTFE in St/MAn binary system and sequent sulfonation is an appropriate method for preparing ion-exchange membrane of VRB

Evaluation of Chitosan-Microcrystalline Cellulose Blends as Direct Compression Excipients

Directory of Open Access Journals (Sweden)

Emmanuel O. Olorunsola

2017-01-01

Full Text Available This study was aimed at evaluating chitosan-microcrystalline cellulose blends as direct compression excipients. Crab shell chitosan, α-lactose monohydrate, and microcrystalline cellulose powders were characterized. Blends of the microcrystalline cellulose and chitosan in ratios 9 : 1, 4 : 1, 2 : 1, and 1 : 1 as direct compression excipients were made to constitute 60% of metronidazole tablets. Similar tablets containing blends of the microcrystalline cellulose and α-lactose monohydrate as well as those containing pure microcrystalline cellulose were also produced. The compact density, tensile strength, porosity, disintegration time, and dissolution rate of tablets were determined. Chitosan had higher moisture content (7.66% and higher moisture sorption capacity (1.33% compared to microcrystalline cellulose and lactose. It also showed better flow properties (Carr’s index of 18.9% and Hausner’s ratio of 1.23. Compact density of tablets increased but tensile strength decreased with increase in the proportion of chitosan in the binary mixtures. In contrast to lactose, the disintegration time increased and the dissolution rate decreased with increase in the proportion of chitosan. This study has shown that chitosan promotes flowability of powder mix and rapid disintegration of tablet. However, incorporation of equal proportions of microcrystalline cellulose and chitosan leads to production of extended-release tablet. Therefore, chitosan promotes tablet disintegration at low concentration and enables extended-release at higher concentration.

Versatile antifouling polyethersulfone filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive.

Science.gov (United States)

Zhao, Yi-Fan; Zhang, Pei-Bin; Sun, Jian; Liu, Cui-Jing; Yi, Zhuan; Zhu, Li-Ping; Xu, You-Yi

2015-06-15

Here we describe the development of versatile antifouling polyethersulfone (PES) filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive. Amphiphilic polyethersulfone-block-poly(2-hydroxyethyl methacrylate) (PES-b-PHEMA) was beforehand designed and used as the blending additive of PES membranes prepared by phase inversion technique. The surface enriched PHEMA blocks on membrane surface acted as an anchor to immobilize the initiating site. Poly(sulfobetaine methacrylate) (PSBMA) were subsequently grafted onto the PES blend membranes by surface-initiated atom transfer radical polymerization (SI-ATRP). The analysis of surface chemistry confirmed the successful grafting of zwitterionic PSBMA brushes on PES membrane surface. The resulted PES-g-PSBMA membranes were capable of separating proteins from protein solution and oil from oil/water emulsion efficiently. Furthermore, the modified membranes showed high hydrophilicity and strongly antifouling properties due to the incorporation of well-defined PSBMA layer. In addition, the PES-g-PSBMA membranes exhibited excellent blood compatibility and durability during the washing process. The developed antifouling PES membranes are versatile and can find their applications in protein filtration, blood purification and oil/water separation, etc. Copyright © 2015 Elsevier Inc. All rights reserved.

Plasma treatment of polyethersulfone membrane for benzene removal from water by air gap membrane distillation.

Science.gov (United States)

Pedram, Sara; Mortaheb, Hamid Reza; Arefi-Khonsari, Farzaneh

2018-01-01

In order to obtain a durable cost-effective membrane for membrane distillation (MD) process, flat sheet polyethersulfone (PES) membranes were modified by an atmospheric pressure nonequilibrium plasma generated using a dielectric barrier discharge in a mixture of argon and hexamethyldisiloxane as the organosilicon precursor. The surface properties of the plasma-modified membranes were characterized by water contact angle (CA), liquid entry pressure, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water CA of the membrane was increased from 64° to 104° by depositing a Si(CH 3 )-rich thin layer. While the pristine PES membrane was not applicable in the MD process, the modified PES membrane could be applied for the first time in an air gap membrane distillation setup for the removal of benzene as a volatile organic compound from water. The experimental design using central composite design and response surface methodology was applied to study the effects of feed temperature, concentration, and flow rate as well as their binary interactions on the overall permeate flux and separation factor. The separation factor and permeation flux of the modified PES membrane at optimum conditions were comparable with those of commercial polytetrafluoroethylene membrane.

Blended Learning

NARCIS (Netherlands)

Van der Baaren, John

2009-01-01

Van der Baaren, J. (2009). Blended Learning. Presentation given at the Mini symposium 'Blended Learning the way to go?'. November, 5, 2009, The Hague, The Netherlands: Netherlands Defence Academy (NDLA).

Hollow fiber ultrafiltration membranes with microstructured inner skin

NARCIS (Netherlands)

Culfaz, P.Z.; Wessling, Matthias; Lammertink, Rob G.H.

2011-01-01

Hollow fiber membranes with microstructured inner surfaces were fabricated from a PES/PVP blend using a spinneret with a microstructured needle. The effect of spinning parameters such as polymer dope flow rate, bore liquid flowrate, air gap and take-up speed on the microstructure and shape of the

Preparation of robust braid-reinforced poly(vinyl chloride) ultrafiltration hollow fiber membrane with antifouling surface and application to filtration of activated sludge solution.

Science.gov (United States)

Zhou, Zhuang; Rajabzadeh, Saeid; Fang, Lifeng; Miyoshi, Taro; Kakihana, Yuriko; Matsuyama, Hideto

2017-08-01

Braid-reinforced hollow fiber membranes with high mechanical properties and considerable antifouling surface were prepared by blending poly(vinyl chloride) (PVC) with poly(vinyl chloride-co-poly(ethylene glycol) methyl ether methacrylate) (poly(VC-co-PEGMA)) copolymer via non-solvent induced phase separation (NIPS). The tensile strength of the braid-reinforced PVC hollow fiber membranes were significantly larger than those of previously reported various types of PVC hollow fiber membranes. The high interfacial bonding strength indicated the good compatibility between the coating materials and the surface of polyethylene terephthalate (PET)-braid. Owing to the surface segregation phenomena, the membrane surface PEGMA coverage increased upon increasing the poly(VC-co-PEGMA)/PVC blending ratio, resulting in higher hydrophilicities and bovine serum albumin (BSA) repulsion. To compare the fouling properties, membranes with similar PWPs were prepared by adjusting the dope solution composition to eliminate the effect of hydrodynamic conditions on the membrane fouling performance. The blend membranes surface exhibited considerable fouling resistance to the molecular adsorption from both BSA solution and activated sludge solution. In both cases, the flux recovered to almost 80% of the initial flux using only water backflush. Considering their great mechanical properties and antifouling resistance to activated sludge solution, these novel membranes show good potential for application in wastewater treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Study of lamellar structure and crystallization behavior of poly(butylene terephthalate (PBT) in PBT/ABS and PBT/ABS/MMA-GMA blends using DSC, SAXS and DMTA

International Nuclear Information System (INIS)

Mantovani, Gerson L.; Pessan, Luiz A.; Hage, Elias; Torriani, Iris L.

2001-01-01

The effects of processing conditions and blend composition in the crystallization behaviour and lamellar structure of poly(butylene terephthalate) (PBT) in blends with acrylonitrile-butadiene-styrene copolymer (ABS) were studied. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and dynamic mechanical thermal analysis (DMTA) were used to observe those effects. Addition of reactive acrylic compatibilizer to the PBT/ABS blends has promoted an increase in the heat of crystallization of the related blends. The Long Period (L), obtained from the peak in the Lorentz-corrected SAXS pattern, was used to observe the effect in the lamellar structure of PBT phase in the blends. The results were in good agreement with the calculated values from de correlation function and the values of L do not show a significant dependence with the PBT mass fraction, either in the binary blends (PBT/ABS) or in the compatibilized blends. A slight but clear increase of the long period (from 3 to 5 angstrom) is noted for the systems injection molded at 240 deg C when compared to the ones molded at 260 deg C, although PBT crystallinity in the blends does not change significantly with blend composition or processing conditions. DMTA curves show a slight shift in the temperature of the tan δ main peaks for both PBT and ABS phases in the compatibilized blends, thereby indicating changes in the degree of miscibility or interaction between phases of those blends. Changes in the compatibilized blends miscibility may be responsible by the effects in the crystallization behaviour and lamellar structure of the PBT/ABS blends. (author)

Study of lamellar structure and crystallization behavior of poly(butylene terephthalate (PBT) in PBT/ABS and PBT/ABS/MMA-GMA blends using DSC, SAXS and DMTA

Energy Technology Data Exchange (ETDEWEB)

Mantovani, Gerson L.; Pessan, Luiz A.; Hage, Elias [Sao Carlos Univ., SP (Brazil). Dept. de Engenharia de Materiais]. E-mail: elias@power.ufscar.br; Plivelic, Tomas S. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil); Torriani, Iris L. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin

2001-07-01

The effects of processing conditions and blend composition in the crystallization behaviour and lamellar structure of poly(butylene terephthalate) (PBT) in blends with acrylonitrile-butadiene-styrene copolymer (ABS) were studied. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and dynamic mechanical thermal analysis (DMTA) were used to observe those effects. Addition of reactive acrylic compatibilizer to the PBT/ABS blends has promoted an increase in the heat of crystallization of the related blends. The Long Period (L), obtained from the peak in the Lorentz-corrected SAXS pattern, was used to observe the effect in the lamellar structure of PBT phase in the blends. The results were in good agreement with the calculated values from de correlation function and the values of L do not show a significant dependence with the PBT mass fraction, either in the binary blends (PBT/ABS) or in the compatibilized blends. A slight but clear increase of the long period (from 3 to 5 angstrom) is noted for the systems injection molded at 240 deg C when compared to the ones molded at 260 deg C, although PBT crystallinity in the blends does not change significantly with blend composition or processing conditions. DMTA curves show a slight shift in the temperature of the tan {delta} main peaks for both PBT and ABS phases in the compatibilized blends, thereby indicating changes in the degree of miscibility or interaction between phases of those blends. Changes in the compatibilized blends miscibility may be responsible by the effects in the crystallization behaviour and lamellar structure of the PBT/ABS blends. (author)

CO2 adsorption using TiO2 composite polymeric membranes: A kinetic study.

Science.gov (United States)

Hafeez, Sarah; Fan, X; Hussain, Arshad; Martín, C F

2015-09-01

CO2 is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas separation by composite membranes. The separation of CO2 by a membrane is not just a process to physically sieve out of CO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb CO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of CO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of CO2 through membranes. Pure cellulose acetate (CA) and cellulose acetate-titania nanoparticle (CA-TiO2) composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended CA-TiO2 membrane adsorbed more quantity of CO2 gas as compared to pure CA membrane. The high CO2 adsorption capacity may enhance the diffusion and solubility of CO2 in the CA-TiO2 composite membrane, which results in a better CO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion models. According to correlation factor R(2), the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion. Copyright © 2015. Published by Elsevier B.V.

Polymer blends

Energy Technology Data Exchange (ETDEWEB)

Allen, Scott D.; Naik, Sanjeev

2017-08-22

The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

Interacting binaries

International Nuclear Information System (INIS)

Eggleton, P.P.; Pringle, J.E.

1985-01-01

This volume contains 15 review articles in the field of binary stars. The subjects reviewed span considerably, from the shortest period of interacting binaries to the longest, symbiotic stars. Also included are articles on Algols, X-ray binaries and Wolf-Rayet stars (single and binary). Contents: Preface. List of Participants. Activity of Contact Binary Systems. Wolf-Rayet Stars and Binarity. Symbiotic Stars. Massive X-ray Binaries. Stars that go Hump in the Night: The SU UMa Stars. Interacting Binaries - Summing Up

Influence of cholesterol and ceramide VI on the structure of multilamellar lipid membranes at water exchange

International Nuclear Information System (INIS)

Ryabova, N. Yu.; Kiselev, M. A.; Balagurov, A. M.

2010-01-01

The structural changes in the multilamellar lipid membranes of dipalmitoylphosphatidylcholine (DPPC)/cholesterol and DPPC/ceramide VI binary systems during hydration and dehydration have been studied by neutron diffraction. The effect of cholesterol and ceramide on the kinetics of water exchange in DPPC membranes is characterized. Compared to pure DPPC, membranes of binary systems swell faster during hydration (with a characteristic time of ∼30 min). Both compounds, ceramide VI and cholesterol, similarly affect the hydration of DPPC membranes, increasing the repeat distance due to the bilayer growth. However, in contrast to cholesterol, ceramide significantly reduces the thickness of the membrane water layer. The introduction of cholesterol into a DPPC membrane slows down the change in the parameters of the bilayer internal structure during dehydration. In the DPPC/ceramide VI/cholesterol ternary system (with a molar cholesterol concentration of 40%), cholesterol is partially released from the lamellar membrane structure into the crystalline phase.

Blended learning

DEFF Research Database (Denmark)

Staugaard, Hans Jørgen

2012-01-01

Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid.......Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid....

The True Ultracool Binary Fraction Using Spectral Binaries

Science.gov (United States)

Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Schmidt, Sarah J.; Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle; Gelino, Chris

2018-01-01

Brown dwarfs bridge the gap between stars and giant planets. While the essential mechanisms governing their formation are not well constrained, binary statistics are a direct outcome of the formation process, and thus provide a means to test formation theories. Observational constraints on the brown dwarf binary fraction place it at 10 ‑ 20%, dominated by imaging studies (85% of systems) with the most common separation at 4 AU. This coincides with the resolution limit of state-of-the-art imaging techniques, suggesting that the binary fraction is underestimated. We have developed a separation-independent method to identify and characterize tightly-separated (dwarfs as spectral binaries by identifying traces of methane in the spectra of late-M and early-L dwarfs. Imaging follow-up of 17 spectral binaries yielded 3 (18%) resolved systems, corroborating the observed binary fraction, but 5 (29%) known binaries were missed, reinforcing the hypothesis that the short-separation systems are undercounted. In order to find the true binary fraction of brown dwarfs, we have compiled a volume-limited, spectroscopic sample of M7-L5 dwarfs and searched for T dwarf companions. In the 25 pc volume, 4 candidates were found, three of which are already confirmed, leading to a spectral binary fraction of 0.95 ± 0.50%, albeit for a specific combination of spectral types. To extract the true binary fraction and determine the biases of the spectral binary method, we have produced a binary population simulation based on different assumptions of the mass function, age distribution, evolutionary models and mass ratio distribution. Applying the correction fraction resulting from this method to the observed spectral binary fraction yields a true binary fraction of 27 ± 4%, which is roughly within 1σ of the binary fraction obtained from high resolution imaging studies, radial velocity and astrometric monitoring. This method can be extended to identify giant planet companions to young brown

Polystyrene/Hyperbranched Polyester Blends and Reactive Polystyrene/Hyperbranched Polyester Blends

National Research Council Canada - National Science Library

Mulkern, Thomas

1999-01-01

.... In this work, the incorporation of HBPs in thermoplastic blends was investigated. Several volume fractions of hydroxyl functionalized hyperbranched polyesters were melt blended with nonreactive polystyrene (PS...

Asymmetric block copolymer membranes with ultrahigh porosity and hierarchical pore structure by plain solvent evaporation

KAUST Repository

Yu, H.

2016-09-14

Membranes with a hierarchical porous structure could be manufactured from a block copolymer blend by pure solvent evaporation. Uniform pores in a 30 nm thin skin layer supported by a macroporous structure were formed. This new process is attractive for membrane production because of its simplicity and the lack of liquid waste.

Asymmetric block copolymer membranes with ultrahigh porosity and hierarchical pore structure by plain solvent evaporation

KAUST Repository

Yu, H.; Qiu, Xiaoyan; Behzad, Ali Reza; Musteata, Valentina-Elena; Smilgies, D.-M.; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

2016-01-01

Membranes with a hierarchical porous structure could be manufactured from a block copolymer blend by pure solvent evaporation. Uniform pores in a 30 nm thin skin layer supported by a macroporous structure were formed. This new process is attractive for membrane production because of its simplicity and the lack of liquid waste.

Electrodialytic Transport Properties of Anion-Exchange Membranes Prepared from Poly(vinyl alcohol) and Poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride).

Science.gov (United States)

Jikihara, Atsushi; Ohashi, Reina; Kakihana, Yuriko; Higa, Mitsuru; Kobayashi, Kenichi

2013-01-02

Random-type anion-exchange membranes (AEMs) have been prepared by blending poly(vinyl alcohol) (PVA) and the random copolymer-type polycation, poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride) at various molar percentages of anion-exchange groups to vinyl alcohol groups, Cpc, and by cross-linking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations, CGA. The characteristics of the random-type AEMs were compared with blend-type AEMs prepared in our previous study. At equal molar percentages of the anion exchange groups, the water content of the random-type AEMs was lower than that of the blend-type AEMs. The effective charge density of the random-type AEMs increased with increasing Cpc and reached a maximum value. Further, the maximum value of the effective charge density increased with increasing CGA. The maximum value of the effective charge density, 0.42 mol/dm3, was obtained for the random-type AEM with Cpc = 4.2 mol % and CGA = 0.15 vol %. A comparison of the random-type and blend-type AEMs with almost the same Cpc showed that the random-type AEMs had lower membrane resistance than the blend-type ones. The membrane resistance and dynamic transport number of the random-type AEM with Cpc = 6.0 mol % and CGA = 0.15 vol % were 4.8 Ω cm2 and 0.83, respectively.

Enhancement of antibacterial activity in nanofillers incorporated PSF/PVP membranes

Science.gov (United States)

Pramila, P.; Gopalakrishnan, N.

2018-04-01

An attempt has been made to investigate the nanofillers incorporated polysulfone (PSF) and polyvinylpyrrolidone (PVP) polymer membranes prepared by phase inversion method. Initially, the nanofillers, viz, Zinc Oxide (ZnO) nanoparticle, Graphene Oxide-Zinc Oxide (GO-ZnO) nanocomposite were synthesized and then directly incorporated into PSF/PVP blend during the preparation of membranes. The prepared membranes have been subjected to FE-SEM, AFM, BET, contact angle, tensile test and anti-bacterial studies. Significant membrane morphologies and nanoporous properties have been observed by FE-SEM and BET, respectively. It has been observed that hydrophilicity, mechanical strength and water permeability of the ZnO and GO-ZnO incorporated membranes were enhanced than bare membrane. Antibacterial activity was assessed by measuring the inhibition zones formed around the membrane by disc-diffusion method using Escherichia coli (gram-negative) as a model bacterium. Again, it has been observed that nanofillers incorporated membrane exhibits high antibacterial performance compared to bare membrane.

Proton-conducting ionic liquid-based proton exchange membrane fuel cell membranes: The key role of ionomer-ionic liquid interaction

Energy Technology Data Exchange (ETDEWEB)

Martinez, Mathieu; Cointeaux, Laure; Iojoiu, Cristina; Lepretre, Jean-Claude; Sanchez, Jean-Yves [LEPMI, UMR 5631, CNRS-INP-UJF, PHELMA-Campus, BP.75, 1130 rue de la Piscine, 38402 Saint-Martin-d' Heres Cedex (France); Molmeret, Yannick; El Kissi, Nadia [Laboratoire de Rheologie, UMR 5520 CNRS-INPG-UJF, ENSHMG, BP 53, 38041 Grenoble (France); Judeinstein, Patrick [Institut de Chimie Moleculaire et des Materiaux d' Orsay (UMR 8182), Batiment 410, Universite Paris-Sud 11, 91405 Orsay Cedex (France)

2010-09-15

The paper deals with the synthesis and characterisation of proton-conducting ionic liquids (PCILs) and their polymer electrolytes obtained by blending modified Nafion membranes with different concentrations of PCILs. The PCILs are obtained by the neutralization of triethylamine with different organic acids. The first part of the paper studies the influence of acidity and acid structure on PCIL thermal and electrochemical performance, while the second part examines membrane conductivity and reveals it to depend more on PCIL structure than on its intrinsic conductivity. At 130 C, conductivities exceeding 10 mS cm{sup -1} were obtained in fully anhydrous conditions. (author)

The population of single and binary white dwarfs of the Galactic bulge

Science.gov (United States)

Torres, S.; García-Berro, E.; Cojocaru, R.; Calamida, A.

2018-05-01

Recent Hubble Space Telescope observations have unveiled the white dwarf cooling sequence of the Galactic bulge. Although the degenerate sequence can be well fitted employing the most up-to-date theoretical cooling sequences, observations show a systematic excess of red objects that cannot be explained by the theoretical models of single carbon-oxygen white dwarfs of the appropriate masses. Here, we present a population synthesis study of the white dwarf cooling sequence of the Galactic bulge that takes into account the populations of both single white dwarfs and binary systems containing at least one white dwarf. These calculations incorporate state-of-the-art cooling sequences for white dwarfs with hydrogen-rich and hydrogen-deficient atmospheres, for both white dwarfs with carbon-oxygen and helium cores, and also take into account detailed prescriptions of the evolutionary history of binary systems. Our Monte Carlo simulator also incorporates all the known observational biases. This allows us to model with a high degree of realism the white dwarf population of the Galactic bulge. We find that the observed excess of red stars can be partially attributed to white dwarf plus main sequence binaries, and to cataclysmic variables or dwarf novae. Our best fit is obtained with a higher binary fraction and an initial mass function slope steeper than standard values, as well as with the inclusion of differential reddening and blending. Our results also show that the possible contribution of double degenerate systems or young and thick-discbulge stars is negligible.

Carbon nanotubes based nafion composite membranes for fuel cell applications

CSIR Research Space (South Africa)

Cele, NP

2009-01-01

Full Text Available Carbon nanotubes (CNTs) containing Nafion composite membranes were prepared via melt-blending at 250 °C. Using three different types of CNTs such as pure CNTs (pCNTs), oxidised CNTs (oCNTs) and amine functionalised CNTs (fCNTs); the effect of CNTs...

Zeolitic Imidazolate Framework-8 Membrane for H2/CO2 Separation: Experimental and Modeling

Science.gov (United States)

Lai, L. S.; Yeong, Y. F.; Lau, K. K.; Azmi, M. S.; Chew, T. L.

2018-03-01

In this work, ZIF-8 membrane synthesized through solvent evaporation secondary seeded growth was tested for single gas permeation and binary gases separation of H2 and CO2. Subsequently, a modified mathematical modeling combining the effects of membrane and support layers was applied to represent the gas transport properties of ZIF-8 membrane. Results showed that, the membrane has exhibited H2/CO2 ideal selectivity of 5.83 and separation factor of 3.28 at 100 kPa and 303 K. Besides, the experimental results were fitted well with the simulated results by demonstrating means absolute error (MAE) values ranged from 1.13 % to 3.88 % for single gas permeation and 10.81 % to 21.22 % for binary gases separation. Based on the simulated data, most of the H2 and CO2 gas molecules have transported through the molecular pores of membrane layer, which was up to 70 %. Thus, the gas transport of the gases is mainly dominated by adsorption and diffusion across the membrane.

Half-metallicity and ferromagnetism of TcX (X=C, Si and Ge) in zinc blende structure

Energy Technology Data Exchange (ETDEWEB)

Liu, Yong [College of Science, Yanshan University, Qinhuangdao 066004 (China); Physics Department, Brock University, St. Catharines, ON, Canada L2S 3A1 (Canada); Xing, Yue [College of Science, Yanshan University, Qinhuangdao 066004 (China); Bose, S.K., E-mail: sbose@brocku.ca [Physics Department, Brock University, St. Catharines, ON, Canada L2S 3A1 (Canada); Zhao, Yong-Hong [Department of Physics, Sichuan Normal University, Chengdu 610068 (China)

2013-02-15

We report results of a first-principles density-functional study of three binary transition-metal compounds TcX (X=C, Si and Ge) in the hypothetical cubic zinc blende (ZB) structure. Our calculations are based on the full potential linear augmented plane wave (FP-LAPW) plus local orbitals method, together with generalized gradient approximation for the exchange-correlation potential. Half-metallic (HM) ferromagnetism is observed in these binary compounds for their optimized cell volumes. In the HM state, these compounds possess an integer magnetic moment (1.000{mu}{sub B}) per formula unit, which is one of the important characteristics of half-metallic ferromagnets (HMFs). The ferromagnetic (FM) state is found to be stable for ZB TcC, TcSi and TcGe against the nonmagnetic (NM) and antiferromagnetic (AFM) states. Calculations show that half-metallicity can be maintained for a wide range of lattice constants in these binary compounds. Density functional calculations of exchange interactions and the Curie temperatures reveal similar trends for the three compounds with respect to the lattice parameter. These compounds are compatible with the traditional semiconductors, and could be useful in spin-electronics and other applications. The most important aspect of this work is to explore the possibility of not only magnetism, but HM ferromagnetism in compounds involving NM elements and 4d transition element Tc. - Highlights: Black-Right-Pointing-Pointer We study magnetism of the compounds TcSi, TcC, and TcGe. Black-Right-Pointing-Pointer These compounds, with nonmagnetic constituents, are found to be ferromagnetic. Black-Right-Pointing-Pointer They show robust half-metallicity in zinc blende structure. Black-Right-Pointing-Pointer Estimated Curie temperatures suggest that synthesis of these compounds is worth pursuing.

Learning to assign binary weights to binary descriptor

Science.gov (United States)

Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

2016-10-01

Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

Modification of HDPE by γ ray radiation in oxygen atmosphere and blend with PA6

International Nuclear Information System (INIS)

Ding Yunsheng; Shi Tiejun; Zhang Zhicheng; Hu Keliang

2002-01-01

A study on the oxidation of high density polyethylene (HDPE) by γ ray irradiation in oxygen atmosphere has been made. The influence of irradiated time on the oxidation has been investigated with the help of Fourier Transform Infrared-Photoacoustics Spectroscopy (FTIR-PAS). Results of FTIR-PAS show after irradiation groups like -C=O, -O-C-O-, O=C-O- were introduced into the HDPE. Although the γ ray has powerful penetrability, the oxidation mainly takes place on the surface of HDPE. after 4 h irradiation in oxygen (dose rate 66 Gy/min.), -C=O is the main group which was introduced into the surface of HDPE. Lengthening the irradiation process makes the pre-produced oxidized section in HDPE surface continue their reactions to yield some oxidation products with the structures of -O-C-O-, O=C-O- and so on. FTIR shows there are reactions or week interaction like hydrogen bond between the irradiated HDPE and PA6 in the binary blends, this is helpful to increase the compatibility of the phase of HDPE and polyamide-6 (PA6) in the blend. Scanning Electron Microscope (SEM) result shows that the interface between HDPE matrix and PA6 domains is much clear and smoother in 0γHDPE/PA6 blends than in 4γHDPE/PA6 and 7γHDPE/PA6 blends. These suggested the miscibility of PA6 and HDPE was improved after HDPE irradiating in oxygen by γ ray radiation

DIFFUSION MEASUREMENTS DURING PERVAPORATION THROUGH A ZEOLITE MEMBRANE

Science.gov (United States)

An isotopic-transient technique was used to directly measure diffusion times of H2O, methanol, ethanol, 2-propanol, and acetone in pure and binary mixture feeds transporting through a zeolite membrane under steady-state pervaporation conditions. Diffusivities can be determ...

Profiling Student Behaviour in a Blended Course: Closing the Gap Between Blended Teaching and Blended Learning

NARCIS (Netherlands)

Bos, Nynke; Brand-Gruwel, Saskia

2018-01-01

Blended learning is often associated with student-oriented learning in which students have varying degrees of control over their learning process. However, the current notion of blended learning is often a teacher- oriented approach in which the teacher identifies the used learning technologies and

Binary Linear-Time Erasure Decoding for Non-Binary LDPC codes

OpenAIRE

Savin, Valentin

2009-01-01

In this paper, we first introduce the extended binary representation of non-binary codes, which corresponds to a covering graph of the bipartite graph associated with the non-binary code. Then we show that non-binary codewords correspond to binary codewords of the extended representation that further satisfy some simplex-constraint: that is, bits lying over the same symbol-node of the non-binary graph must form a codeword of a simplex code. Applied to the binary erasure channel, this descript...

Effect of blending temperature on the mechanical properties of PVC/ENR blend upon irradiation

International Nuclear Information System (INIS)

Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan; Nasir, M.; Baharin, A.

2000-01-01

Poly (vinyl chloride) / epoxidized natural rubber blends were prepared with a Brabender plasticorder at 140, 150, 160, 170 and 180 degree C mixing temperatures. They were mixed at 50 rpm rotor speed for 10 min. The blends were irradiated with doses ranging from 0-200 kGy. Changes in tensile strength, modulus at 100% elongation, gel fraction and damping properties (tan δ) of the blends with increasing mixing temperatures and irradiation doses were investigated. In general, it was observed that the mixing temperature is important in maximizing the positive effect of irradiation. Results revealed that a readily miscible blend enjoy maximum benefit from irradiation meanwhile irradiation impart miscibility to a partially miscible PVC/ENR blend. The enhancement in blend properties is believed to be attributed by the irradiation-induced crosslinking along with irradiation-induced interaction between the polymers. The radiation-induced degradation found to be prominent at higher doses for blend that has undergone excessive thermal degradation. However evidence did not reveal the specific nature of radiation-induced reaction responsible for the improved interactions of the blends. (author)

Four W Ursae Majoris contact binaries in the old galactic cluster NGC 188

International Nuclear Information System (INIS)

Baliunas, S.L.; Guinan, E.F.

1984-01-01

The authors calculated the cross-correlation coefficients between the spectra of the contact binaries and slowly-rotating template stars of approximately the same color in NGC 188 (stars I-32 and I-33). From the cross-correlation coefficients they measured the radial velocities of the W UMa stars near the expected phase of velocity crossing with respect to the two other cluster stars. The velocities of the W UMa systems are consistent with cluster membership. In three of the systems, the spectra were obtained at phases where individual stellar components were resolved. Two Gaussians were fit simultaneously to the most significant portion of the blended cross-correlation peaks. The mass ratios of these three systems were determined by assuming that the velocity of the center of mass is equal to the mean radial velocity of the two cluster reference stars. The mass ratios in these three systems suggest the binaries are similar to other short-period, field W UMa systems designated W-type

Blending Words Found In Social Media

Directory of Open Access Journals (Sweden)

Giyatmi Giyatmi

2017-12-01

Full Text Available There are many new words from the social media such as Netizen, Trentop, and Delcon. Those words include in blending. Blending is one of word formations combining two clipped words to form a brand new word. The researchers are interested in analyzing blend words used in the social media such as Instagram, Twitter, Facebook, and Blackberry Messenger. This research aims at (1 finding blend words used in the social media (2 describing kinds of blend words used in social media (3 describing the process of blend word formation used in the social media. This research uses some theories dealing with definition of blending and kinds of blending. This research belongs to descriptive qualitative research. Data of the research are English blend words used in social media. Data sources of this research are websites consisting of some English words used in social media and some social media users as the informant. Techniques of data collecting in this research are observation and simak catat. Observation is by observing some websites consisting of some English words used in social media. Simak catat is done by taking some notes on the data and encoding in symbols such as No/Blend words/Kinds of Blending. The researchers use source triangulation to check the data from the researchers with the informant and theory triangulation to determine kinds of blending and blend word formation in social media. There are115 data of blend words. Those data consists of 65 data of Instagram, 47 data of Twitter, 1 datum of Facebook, and 2 data of Blackberry Messenger. There are 2 types of blending used in social media;108 data of blending with clipping and 7 data of blending with overlapping. There are 10 ways of blend word formation found in this research.

Design Principles for the Blend in Blended Learning: A Collective Case Study

Science.gov (United States)

Lai, Ming; Lam, Kwok Man; Lim, Cher Ping

2016-01-01

This paper reports on a collective case study of three blended courses taught by different instructors in a higher education institution, with the purpose of identifying the different types of blend and how the blend supports student learning. Based on the instructors' and students' interviews, and document analysis of course outlines, two major…

Binary effectivity rules

DEFF Research Database (Denmark)

Keiding, Hans; Peleg, Bezalel

2006-01-01

is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...

Blended acquisition with dispersed source arrays

NARCIS (Netherlands)

Berkhout, A.J.

2012-01-01

Blended source arrays are historically configured with equal source units, such as broadband vibrators (land) and broadband air-gun arrays (marine). I refer to this concept as homogeneous blending. I have proposed to extend the blending concept to inhomogeneous blending, meaning that a blended

Reconciliation of Cahn-Hilliard predictions for spinodal decomposition lengthscales in polymer blends

Science.gov (United States)

Cabral, Joao

Spinodal decomposition (SD) of partially miscible polymer blends can yield well-defined nanostructures with prescribed lengthscales and connectivity, and applications ranging from membranes and scaffolds to photovoltaics. Cahn-Hilliard-Cook (CHC) theory estimates the initial, dominant SD wavenumber to be qm =√{G''/4 k } , where G'' is the second derivative of the free energy of mixing with respect to concentration and k is a structural parameter which can be computed from the segment lengths and volumes of monomer units. Tuning G'', with quench depth into the two phase region, for instance, should thus provide a facile and precise means for designing polymeric bicontinuous structures. The fulfillment of this potential rests on the thermodynamics of available polymer systems, coarsening kinetics, as well as engineering constraints. We extensively review experimental measurements of G'' in both one- and two-phase blend systems, and critically examine the accuracy of this fundamental prediction against achievements over the past 4 decades of polymer blend demixing. Despite widespread misconceptions in detecting and describing SD, we find the CHC relation to be remarkably accurate and conclude with design considerations and limitations for polymer nanostructures via SD, reflecting on John Cahn's contributions to the field.

Novel MOF-membrane for molecular sieving predicted by IR-diffusion studies and molecular modeling

NARCIS (Netherlands)

Bux, H.; Chmelik, C.; van Baten, J.M.; Krishna, R.; Caro, J.

2010-01-01

The predicted permeation selectivity of a binary gas mixture for a metal-organic framework ZIF-8 membrane was estimated from combined Grand Canonical Monte Carlo (GCMC) simulations and infrared microscopy (IRM) data and compared with permeation measurements on a ZIF-8 membrane. It is shown that

Blended Learning

Science.gov (United States)

Imbriale, Ryan

2013-01-01

Teachers always have been and always will be the essential element in the classroom. They can create magic inside four walls, but they have never been able to create learning environments outside the classroom like they can today, thanks to blended learning. Blended learning allows students and teachers to break free of the isolation of the…

Apparatus for blending small particles

International Nuclear Information System (INIS)

Bradley, R.A.; Reese, C.R.; Sease, J.D.

1975-01-01

An apparatus is described for blending small particles and uniformly loading the blended particles in a receptacle. Measured volumes of various particles are simultaneously fed into a funnel to accomplish radial blending and then directed onto the apex of a conical splitter which collects the blended particles in a multiplicity of equal subvolumes. Thereafter the apparatus sequentially discharges the subvolumes for loading in a receptacle. A system for blending nuclear fuel particles and loading them into fuel rod molds is described in a preferred embodiment

Contribution made by multivariate curve resolution applied to gel permeation chromatography-Fourier transform infrared data for an in-depth characterization of styrene-butadiene rubber blends.

Science.gov (United States)

Ruckebusch, C; Vilmin, F; Coste, N; Huvenne, J P

2008-07-01

We evaluate the contribution made by multivariate curve resolution-alternating least squares (MCR-ALS) for resolving gel permeation chromatography-Fourier transform infrared (GPC-FT-IR) data collected on butadiene rubber (BR) and styrene butadiene rubber (SBR) blends in order to access in-depth knowledge of polymers along the molecular weight distribution (MWD). In the BR-SBR case, individual polymers differ in chemical composition but share almost the same MWD. Principal component analysis (PCA) gives a general overview of the data structure and attests to the feasibility of modeling blends as a binary system. MCR-ALS is then performed. It allows resolving the chromatographic coelution and validates the chosen methodology. For SBR-SBR blends, the problem is more challenging since the individual elastomers present the same chemical composition. Rank deficiency is detected from the PCA data structure analysis. MCR-ALS is thus performed on column-wise augmented matrices. It brings very useful insight into the composition of the analyzed blends. In particular, a weak change in the composition of individual SBR in the MWD's lowest mass region is revealed.

Synthesis and characterization of sulfonate polystyrene-lignosulfonate-alumina (SPS-LS-Al{sub 2}O{sub 3}) polyblends as electrolyte membranes for fuel cell

Energy Technology Data Exchange (ETDEWEB)

Gonggo, Siang Tandi, E-mail: standigonggo@yahoo.com [Chemistry Research Groups, Faculty of Teacher Training and Educational Sciences, Tadulako University (Indonesia)

2015-09-30

The new type of electrolyte membrane materials has been prepared by blend sulfonated polystyrene (SPS), lignosulfonate (LS), and alumina (SPS-LS-Al{sub 2}O{sub 3}) by casting polymer solution. The resulting polymer electrolyte membranes were then characterized by functional groups analysis, mechanical properties, water uptake, ion exchange capacity, and proton conductivity. SPS-LS-Al{sub 2}O{sub 3} membranes with alumina composition various have been proven qualitatively by analysis of functional groups. Increasing the Al{sub 2}O{sub 3} ratio resulted in higher ion exchange capacity (IEC), mechanical strength and proton conductivity, but water uptake decreased. The SPS-LS-Al{sub 2}O{sub 3} blend showed higher proton conductivity than Nafion 117.

Durability of Selected Membrane Materials when Exposed to Chlorine Gas

Energy Technology Data Exchange (ETDEWEB)

Eikeland, Marianne Soerflaten

2001-03-01

This thesis is focusing on the durability of selected membrane materials when exposed to chlorine gas in the temperature range 30-100{sup o}C. Studies of the changes of membrane separation properties and the mechanisms promoting these changes have been studied. The selected membrane materials were poly(dimethylsioxane) (PDMS), Fluorel, fluorosilicone, and blends of PDMS and Fluorel. The thesis is organised in seven chapters. The first chapter gives an introduction to the background of the work. The second chapter presents the theory for gas separation using dense rubbery membranes. The properties of the selected membrane materials are presented in chapter three. The fourth chapter describes degradation mechanisms for polymeric materials in general and for the selected membrane materials in particular. Presentation of the experimental work is given in chapter five, while the results with discussions are presented in chapter six. The conclusions and recommendations for further studies are given in chapter seven. Five appendixes are attached: Appendix A describes the calculations of permeability and solubility coefficients and the accuracy of the experimental measurements. Appendix B summarises the measured values in tables and Appendix C describes the analytical methods. Appendix D gives the properties of the gases used in the experiments. Appendix E is the article ''Durability of Poly(dimethylsiloxane) when Exposed to Chlorine Gas'', submitted to the Journal of Applied Polymer Science. Highly crosslinked PDMS was found to have an initial high permeability for chlorine gas and a high Cl{sub 2}/O{sub 2} selectivity. However when exposed to chlorine gas the permeability decreased significantly. Crosslinking of the PDMS polymer chain and chlorination of the polymer gave a denser polymer structure and thus lower permeability. Fluorel showed very low permeabilities and selectivities for the gases in question and was thus not interesting for this

Radiation-modified blends of the basis of polyethylene terephthalate and polypropylene

International Nuclear Information System (INIS)

Mery-Meri, R.; Revyakin, O.; Zicans, J.

2000-01-01

The binary composite systems on the basis of post-consumer poly-(ethylene terephthalate) and polypropylene have been investigated. Mechanical properties of the compositions were studied in detail in order to expand the application possibilities of tested binary composites. Structural changes of the poly (ethylene terephthalate) / polypropylene blends depending on the concentration of the components were investigated also. Additionally, the optimum processing conditions were established. Particular attention was paid to study the influence of the ionizing γ-radiation on the structural and mechanical properties of the composition systems tested. The magnitude of the adsorbed dose od γ-radiation was established to affect differently the structure of poly(ethylene terephalate) and polypropylene. At small absorbed doses (50 kGy) crosslinking of the polymer was observed for both poly(ethylene terephthalate) and polypropylene resulting in the increase of some mechanical properties of pure materials as well of their compositions, whereas the absorbed dose of 300 kGy caused the destruction of the tested materials. It is important to mention that the rate of radiation-chemical destruction of polypropylene is higher than poly(ethylene terephthalate) destruction rate. (author)

Fabrication of PVDF-based blend membrane with a thin hydrophilic deposition layer and a network structure supporting layer via the thermally induced phase separation followed by non-solvent induced phase separation process

Science.gov (United States)

Wu, Zhiguo; Cui, Zhenyu; Li, Tianyu; Qin, Shuhao; He, Benqiao; Han, Na; Li, Jianxin

2017-10-01

A simple strategy of thermally induced phase separation followed by non-solvent induced phase separation (TIPS-NIPS) is reported to fabricate poly (vinylidene fluoride) (PVDF)-based blend membrane. The dissolved poly (styrene-co-maleic anhydride) (SMA) in diluent prevents the crystallization of PVDF during the cooling process and deposites on the established PVDF matrix in the later extraction. Compared with traditional coating technique, this one-step TIPS-NIPS method can not only fabricate a supporting layer with an interconnected network structure even via solid-liquid phase separation of TIPS, but also form a uniform SMA skin layer approximately as thin as 200 nm via surface deposition of NIPS. Besides the better hydrophilicity, what's interesting is that the BSA rejection ratio increases from 48% to 94% with the increase of SMA, which indicates that the separation performance has improved. This strategy can be conveniently extended to the creation of firmly thin layer, surface functionalization and structure controllability of the membrane.

Phase Behavior of Diblock Copolymer–Homopolymer Ternary Blends: Congruent First-Order Lamellar–Disorder Transition

Energy Technology Data Exchange (ETDEWEB)

Hickey, Robert J.; Gillard, Timothy M.; Irwin, Matthew T.; Morse, David C.; Lodge, Timothy P.; Bates, Frank S. (UMM)

2016-10-13

We have established the existence of a line of congruent first-order lamellar-to-disorder (LAM–DIS) transitions when appropriate amounts of poly(cyclohexylethylene) (C) and poly(ethylene) (E) homopolymers are mixed with a corresponding compositionally symmetric CE diblock copolymer. The line of congruent transitions, or the congruent isopleth, terminates at the bicontinuous microemulsion (BμE) channel, and its trajectory appears to be influenced by the critical composition of the C/E binary homopolymer blend. Blends satisfying congruency undergo a direct LAM–DIS transition without passing through a two-phase region. We present complementary optical transmission, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and dynamic mechanical spectroscopy (DMS) results that establish the phase behavior at constant copolymer volume fraction and varying C/E homopolymer volume ratios. Adjacent to the congruent composition at constant copolymer volume fraction, the lamellar and disordered phases are separated by two-phase coexistence windows, which converge, along with the line of congruent transitions, at an overall composition in the phase prism coincident with the BμE channel. Hexagonal and cubic (double gyroid) phases occur at higher diblock copolymer concentrations for asymmetric amounts of C and E homopolymers. These results establish a quantitative method for identifying the detailed phase behavior of ternary diblock copolymer–homopolymer blends, especially in the vicinity of the BμE.

Investigation of diesel-ethanol blended fuel properties with palm methyl ester as co-solvent and blends enhancer

Directory of Open Access Journals (Sweden)

Mat Taib Norhidayah

2017-01-01

Full Text Available Diesel engine is known as the most efficient engine with high efficiency and power but always reported as high fuel emission. Malaysia National Automotive Policy (NAP was targeting to improve competitive regional focusing on green technology development in reducing the emission of the engine. Therefore, ethanol was introduced to reduce the emission of the engine and while increasing its performance, Palm methyl ester was introduced as blend enhancer to improve engine performance and improve diesel-ethanol blends stability. This paper aimed to study the characteristics of the blends and to prove the ability of palm-methyl-ester as co-solvent in ethanol-diesel blends. Stability and thermophysical test were carried out for different fuel compositions. The stability of diesel-ethanol blended was proved to be improved with the addition of PME at the longer period and the stability of the blends changed depending on temperature and ethanol content. Density and viscosity of diesel-ethanol-PME blends also give higher result than diesel-ethanol blends and it's proved that PME is able to increase density and viscosity of blends. Besides, heating value of the blends also increases with the increasing PME in diesel-ethanol blends.

Largely enhanced dielectric properties of carbon nanotubes/polyvinylidene fluoride binary nanocomposites by loading a few boron nitride nanosheets

International Nuclear Information System (INIS)

Yang, Minhao; Zhao, Hang; He, Delong; Bai, Jinbo

2016-01-01

The ternary nanocomposites of boron nitride nanosheets (BNNSs)/carbon nanotubes (CNTs)/polyvinylidene fluoride (PVDF) are fabricated via a combination of solution casting and extrusion-injection processes. The effects of BNNSs on the electrical conductivity, dielectric behavior, and microstructure changes of CNTs/PVDF binary nanocomposites are systematically investigated. A low percolation value (f_c) for the CNTs/PVDF binary system is obtained due to the integration of solution and melting blending procedures. Two kinds of CNTs/PVDF binary systems with various CNTs contents (f_C_N_T_s) as the matrix are discussed. The results reveal that compared with CNTs/PVDF binary systems at the same f_C_N_T_s, the ternary BNNSs/CNTs/PVDF nanocomposites exhibit largely enhanced dielectric properties due to the improvement of the CNTs dispersion state and the conductive network. The dielectric constant of CNTs/PVDF binary nanocomposite with 6 vol. % CNTs (f_C_N_T_s   f_c), it displays a 43.32% improvement from 1325 to 1899 after the addition of 3 vol. % BNNSs. The presence of BNNSs facilitates the formation of the denser conductive network. Meanwhile, the ternary BNNSs/CNTs/PVDF systems exhibit a low dielectric loss. The adjustable dielectric properties could be obtained by employing the ternary systems due to the microstructure changes of nanocomposites.

EXPERIMENTAL DESIGN AND RESPONSE SURFACE MODELING OF PI/PES-ZEOLITE 4A MIXED MATRIX MEMBRANE FOR CO2 SEPARATION

Directory of Open Access Journals (Sweden)

T. D. KUSWORO

2015-09-01

Full Text Available This paper investigates the effect of preparation of polyimide/polyethersulfone (PI/PES blending-zeolite mixed matrix membrane through the manipulation of membrane production variables such as polymer concentration, blending composition and zeolite loading. Combination of central composite design and response surface methodology were applied to determine the main effect and interaction effects of these variables on membrane separation performance. The quadratic models between each response and the independent parameters were developed and the response surface models were tested with analysis of variance (ANOVA. In this study, PI/ (PES–zeolite 4A mixed matrix membranes were casted using dry/wet phase inversion technique. The separation performance of mixed matrix membrane had been tested using pure gases such as CO2 and CH4. The results showed that zeolite loading was the most significant variable that influenced the CO2/CH4 selectivity among three variables and the experimental results were in good agreement with those predicted by the proposed regression models. The gas separation performance of the membrane was relatively higher as compare to polymeric membrane. Therefore, combination of central composite design and response surface methodology can be used to prepare optimal condition for mixed matrix membrane fabrication. The incorporation of 20 wt% zeolite 4A into 25 wt% of PI/PES matrix had resulted in a high separation performance of membrane material.

Preparation and Characterization of HDPE/EVA Flat Sheet Membranes by Thermally Induced Phase Separation Method

Directory of Open Access Journals (Sweden)

Zahra Shoeyb

2015-06-01

Full Text Available The adjustment of material composition in fabrication of modified polymeric membrane has been considered the most efficient and easiest method. For this purpose blended membranes of high density polyethylene (HDPE–ethylene vinyl acetate (EVA were prepared by thermally induced phase separation method. The impact of EVA in the presence of diluent on the crystalization temperature was assessed using differential scanning calorimetry (DSC. The obtained results showed that EVA has no significant effect on the crystalization temperature of HDPE. The absorption frequencies at 1248 and 1749 cm-1, respectively, due to C-O and C=O streching vibrations of EVA functional groups, confirmed the existence of EVA in HDPE membrane. The pure water permeability of HDPE/EVA blend was measured and compared with that of neat HDPE membrane. The results showed that an EVA content up to 2.5 wt% raised water permeability considerably and the leafy structure of the membranes contracted and the pure water permeation dropped with higher EVA content. The results of porosity measurement and scanning electronic microscopic (SEM analysis also confirmed these findings. Contact angel measurements and atomic force microscopy (AFM examinations and static absorption of collagen protein on the membrane surfaces revealed that EVA content up to 5 wt% lowered the hydrophobicity of the membrane. By EVA content above 10 wt%, due to the structural alteration on the membrane surface, the contact angel and the collagen absorption on the surface of membrane increased. The measurement of tensile strength showed that with increasing EVA content the mechanical properties of the membranes improved due to interactions of polar groups in EVA.

Preparation and water desalination properties of POSS-polyamide nanocomposite reverse osmosis membranes

KAUST Repository

Duan, Jintang; Litwiller, Eric; Pinnau, Ingo

2015-01-01

osmosis membranes was systematically investigated. Four POSS materials (P-8Phenyl, P-8NH3Cl, P-8NH2 and P-1NH2) were introduced into the selective layer by physical blending or chemical fixation during standard interfacial polymerization. Water flux and Na

A structural study of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 at high pressure

CERN Document Server

Kozlenko, D P; Hull, S; Knorr, K; Savenko, B N; Shchennikov, V V; Voronin, V I

2002-01-01

The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of the Landau theory of phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e sub 4. This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides

Radiation effect on PVC/ENR blends

International Nuclear Information System (INIS)

Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan

1997-01-01

The effect of irradiation on the physical properties of Polyvinyl Chloride / Epoxidised Natural Rubber Blends (PVC/ENR blends) were investigated. The enhancement in tensile strength, elongation at break, hardness and aging properties of the blends have confirmed the positive effect of irradiation on the blends. It is evident from gel fraction and infra red spectroscopic studies that the blends of PVC and ENR cross-linked upon irradiation. The results also revealed that at any blend composition, the enhancement in properties depend on irradiation dose which controls the degree of radiation induced cross-linking. In an attempt to maximize the constructive effect of irradiation, the influence of various additives such as stabilizers, radiation sensitizers, fillers and processing aids on the blend properties were studied. The changes in blend properties upon irradiation with the presents of above additives were also presented in this paper

Blending into the mix

Energy Technology Data Exchange (ETDEWEB)

Adams, R.G.; Gibb, W.H.; Majid, K.A. [Power Technology (United Kingdom)

1999-07-01

Successful coal blending requires finding a careful balance between fuel costs and plant performance. A recent study of a Malaysian power plant shows how the utility (Tenaga Nasional Berhad (TNB)) could reduce fuel costs while avoiding boiler operating problems normally associated with firing low-grade coals. TNB`s Kaper 2220 MW power station in Selangor needed an improved method of coal blending for two new 500 MW units and for two existing 300 MW units. UK`s Power Technology was commissioned to identify what coal blends the boiler could tolerate. A Coal Quality Impact Model (CQIM) analysis of the effect of different coals and coal blends on combustion performance and economics, and a performance analysis of coal yard handling facility was made to determine whether the accuracy of the required blend could be achieved (using a Coal Handling Simulation, CHAS, software package). The CQIM study showed that the proportion of cheaper coals could be increased from 20% to 50% provided each shipment was adequately sampled. The CHAS study showed that use of a flat back reclaimer or modifications to the dry coal stove would allow accurate blending. 5 figs., 1 tab.

Chitosan/Carboxymethylcellulose/Ionic Liquid/Ag(0) Nanoparticles Form a Membrane with Antimicrobial Activity

International Nuclear Information System (INIS)

Quadros, C.; Faria, V.W.; Scheeren, C.W.; Klein, M.P.; Hertz, P.F.

2013-01-01

Silver metal nanoparticles were immobilized in chitosan/carboxymethylcellulose/BMI.BF4(1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid) (CS/CMC/IL) to form polymeric membrane with 20 μm thickness. The CS/CMC/IL polymeric membrane was prepared using a simple solution blending method. Irregularly shaped Ag(0) nanoparticles with monomodal size distributions of nm Ag(0) were immobilized in the membrane. The presence of small Ag(0) nanoparticles induced an augmentation in the CS/CMC/IL film surface areas. The CS/CMC/IL membrane containing Ag(0) showed increase antimicrobial activity the Ag(0) concentration increased up to saturation at 10 mg. CS/CMC/IL membrane that contains Ag(0) nanoparticles has enhanced durability of the membrane and exhibited stronger antimicrobial activity against Escherichia coli and Staphylococcus aureus.

Decentralized Blended Acquisition

NARCIS (Netherlands)

Berkhout, A.J.

2013-01-01

The concept of blending and deblending is reviewed, making use of traditional and dispersed source arrays. The network concept of distributed blended acquisition is introduced. A million-trace robot system is proposed, illustrating that decentralization may bring about a revolution in the way we

Visualization and analysis of lipopolysaccharide distribution in binary phospholipid bilayers

Energy Technology Data Exchange (ETDEWEB)

Henning, Maria Florencia [Instituto de Investigaciones Bioquimicas La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Medicas, UNLP, Calles 60 y 120, 1900 La Plata (Argentina); Sanchez, Susana [Laboratory for Fluorescence Dynamics, University of California-Irvine, Irvine, CA (United States); Bakas, Laura, E-mail: lbakas@biol.unlp.edu.ar [Instituto de Investigaciones Bioquimicas La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Medicas, UNLP, Calles 60 y 120, 1900 La Plata (Argentina); Departamento de Ciencias Biologicas, Facultad de Ciencias Exactas, UNLP, Calles 47 y 115, 1900 La Plata (Argentina)

2009-05-22

Lipopolysaccharide (LPS) is an endotoxin released from the outer membrane of Gram-negative bacteria during infections. It have been reported that LPS may play a role in the outer membrane of bacteria similar to that of cholesterol in eukaryotic plasma membranes. In this article we compare the effect of introducing LPS or cholesterol in liposomes made of dipalmitoylphosphatidylcholine/dioleoylphosphatidylcholine on the solubilization process by Triton X-100. The results show that liposomes containing LPS or cholesterol are more resistant to solubilization by Triton X-100 than the binary phospholipid mixtures at 4 {sup o}C. The LPS distribution was analyzed on GUVs of DPPC:DOPC using FITC-LPS. Solid and liquid-crystalline domains were visualized labeling the GUVs with LAURDAN and GP images were acquired using a two-photon microscope. The images show a selective distribution of LPS in gel domains. Our results support the hypothesis that LPS could aggregate and concentrate selectively in biological membranes providing a mechanism to bring together several components of the LPS-sensing machinery.

Blended Learning: enabling Higher Education Reform

Directory of Open Access Journals (Sweden)

Kathleen Matheos

2018-01-01

Full Text Available Blended learning research and practice have been areas of growth for two decades in Canada, with over 95% of Canadian higher education institutions involved in some form of blended learning. Despite strong evidence based research and practice blended learning, for the most part, has remained at sidelined in Canadian universities. The article argues the need for blended learning to situate itself within the timely and crucial Higher Education Reform (HER agenda. By aligning the affordances of blended learning with the components of HER, blended learning can clearly serve as an enabler for HER.

Biocompatibility studies of polyacrylonitrile membranes modified with carboxylated polyetherimide

Energy Technology Data Exchange (ETDEWEB)

Senthilkumar, S.; Rajesh, S.; Jayalakshmi, A.; Mohan, D., E-mail: mohantarun@gmail.com

2013-10-15

Poly (ether-imide) (PEI) was carboxylated and used as the hydrophilic modification agent for the preparation of polyacrylonitrile (PAN) membranes. Membranes were prepared with different blend compositions of PAN and CPEI by diffusion induced precipitation. The modified membranes were characterized by thermo gravimetric analysis (TGA), mechanical analysis, scanning electron microscopy (SEM) and contact angle measurement to understand the influence of CPEI on the properties of the membranes. The biocompatibility studies exhibited reduced plasma protein adsorption, platelet adhesion and thrombus formation on the modified membrane surface. The complete blood count (CBC) results of CPEI incorporated membranes showed stable CBC values and significant decrease in the complement activation were also observed. In addition to good cytocompatibility, monocytes cultured on these modified membranes exhibited improved functional profiles in 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Thus it could be concluded that PAN/CPEI membranes with excellent biocompatibility can be useful for hemodialysis. Highlights: • Carboxylated PEI was prepared and utilized as hydrophilic modification agent. • CPEI incorporated into PAN to improved biocompatibility and cyto compatibility • Biocompatibility of membranes was correlated with morphology and hydrophilicity. • Antifouling studies of the PAN/CPEI membranes was studied by BSA as model foulant.

Membrane-based technologies for biogas separations.

Science.gov (United States)

Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

2010-02-01

Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

Multicomponent transport in membranes for redox flow batteries

Science.gov (United States)

Monroe, Charles

2015-03-01

Redox flow batteries (RFBs) incorporate separator membranes, which ideally prevent mixing of electrochemically active species while permitting crossover of inactive supporting ions. Understanding crossover and membrane selectivity may require multicomponent transport models that account for solute/solute interactions within the membrane, as well as solute/membrane interactions. Application of the Onsager-Stefan-Maxwell formalism allows one to account for all the dissipative phenomena that may accompany component fluxes through RFB membranes. The magnitudes of dissipative interactions (diffusional drag forces) are quantified by matching experimentally established concentration transients with theory. Such transients can be measured non-invasively using DC conductometry, but the accuracy of this method requires precise characterization of the bulk RFB electrolytes. Aqueous solutions containing both vanadyl sulfate (VOSO4) and sulfuric acid (H2SO4) are relevant to RFB technology. One of the first precise characterizations of aqueous vanadyl sulfate has been implemented and will be reported. To assess the viability of a separator for vanadium RFB applications with cell-level simulations, it is critical to understand the tendencies of various classes of membranes to absorb (uptake) active species, and to know the relative rates of active-species and supporting-electrolyte diffusion. It is also of practical interest to investigate the simultaneous diffusion of active species and supports, because interactions between solutes may ultimately affect the charge efficiency and power efficiency of the RFB system as a whole. A novel implementation of Barnes's classical model of dialysis-cell diffusion [Physics 5:1 (1934) 4-8] is developed to measure the binary diffusion coefficients and sorption equilibria for single solutes (VOSO4 or H2SO4) in porous membranes and cation-exchange membranes. With the binary diffusion and uptake measurement in hand, a computer simulation that

Physicochemical properties of macrogol ointment and emulsion ointment blend developed for regulation of water absorption.

Science.gov (United States)

Noda, Yasuhiro; Watanabe, Kazuya; Sanagawa, Akimasa; Sobajima, Yu; Fujii, Satoshi

2011-10-31

Pressure ulcers can form with excess pressure and shearing stress on skin tissue. Because pressure ulcer is often accompanies by exudates, selection of appropriate topical emulsion ointment is difficult. Blended ointments consisting of emulsion base and water-soluble base are clinically used for adjustment of wound moist environment. Because regulating the amount of wound exudates can enhance treatment efficacy, two new blended ointments were developed. LY-SL blended ointment consisted of lysozyme hydrochloride water-in-oil (w/o) emulsion (LY-cream) and sulfadiazine macrogol (polyethylene glycol) ointment (SL-pasta). TR-SL blended ointment consisted of tretinoin tocoferil oil-in-water (o/w) emulsion (TR-cream) and SL-pasta (TR-SL). LY-SL and TR-SL were applied to Franz diffusion cell with cellulose membranes for the evaluation of water absorption characteristics at 32 °C. Water absorption rate constants (mg/cm(2)/min(0.5)) were 12.5, 16.3 and 34.6 for LY-cream, TR-cream and SL-pasta, respectively. Water absorption rate constants for LY-SL and TR-SL (SL-pasta 70%) exhibited intermediate values of 21.2 and 27.2, as compared to each ointment alone, respectively. Because amount of water absorbed was linearly related to square root of time, it was suggested that water-absorbable macrogol was surrounded by oily ingredients forming matrix structure. This diffusion-limited structure may regulate water absorption capacity. This is the first report of physicochemical properties of macrogol ointment and emulsion ointment blend developed for regulation of water absorption. The blended ointment can properly regulate amount of exudates in wounds and may be useful for treatment of pressure ulcers. Copyright © 2011 Elsevier B.V. All rights reserved.

Influence of SEBS-MA and SBS compatibilizers on properties and morphology of blends of polystyrene/rubber residue (SBRr from the footwear industry

Directory of Open Access Journals (Sweden)

Carlos Bruno Barreto Luna

Full Text Available Abstract The reuse of rubber waste is very important today, both to reduce the harmful effects on the environment, and to reduce the cost of new material development. Considering that most of the studies reported in literature refer to the reuse of tire waste, this article aims to evaluate the influence of styrene-butadiene-styrene (SBS and styrene-(ethylene-butylene-styrene grafted with maleic anhydride (SEBS-MA compatibilizers on the blend performance of polystyrene (PS/styrene-butadiene rubber residue (SBRr, which come from the footwear industry. The blends were prepared in a co-rotating twin screw extruder and then were molded by injection. They were analyzed by impact and tensile tests, heat deflection temperature (HDT, ductile-brittle transition temperature, dynamic mechanical thermal analysis (DMTA and transmission electron microscopy (TEM. The results evidenced that the use of any of the compatibilizers on the PS/SBRr blend significantly increased the impact strength, while the tensile properties and HDT were lower when compared to the polymer matrix. The ductile-brittle transition temperature remains at approximately 25°C range for all the blends. In general, it has been proved that the SBS was the most effective compatibilization process in the PS/SBRr system. The DMTA test shows the presence of two distinct temperature peaks. The morphologies obtained by TEM of binary and ternary blends were quite different and typical of immiscible blend. The results show a good perspective regarding the use of industrial waste (SBRr, since it may enhance a material that would be discarded.

Physico-chemical properties of blends of palm olein with other vegetable oils

Directory of Open Access Journals (Sweden)

Mobin Siddique, Bazlul

2010-12-01

Full Text Available Palm oil (olein was blended with other edible oils for the enhancement of its market acceptability in terms of melting point depression and shelf life. The physico-chemical properties like viscosity, density, melting behavior, peroxide value (PV, saponification value (SV and iodine value (IV of four different binary blends with four vegetable oils were evaluated. Palm olein was found to be more stable against rancidity than the other oils. For the stability against oxidation and melting point depression the palm olein-canola (PO/CO blend was found to be better than the others. The Differential Scanning Calorimeter (DSC thermogram of the melting behavior of the blends traces some new polymorphs of the triglyceride. This study will help the oil producing industry to find out the most economically viable oil blends for cooking purposes, with maximum nutrition as well as desirable physico-chemical properties.

Aceite de palma (oleína fue mezclada con otros aceites comestibles para aumentar su aceptabilidad en el mercado en términos de descenso del punto de fusión y mejora de su almacenamiento. Las propiedades físico-químicas tales como viscosidad, densidad, comportamiento en la fusión, valor de peróxidos (PV, valor de saponificación (SV e índice de yodo (IV de cuatro diferentes mezclas binarias con cuatro aceites vegetales fueron evaluadas. La oleína de palma fue más estable frente a la rancidez que otros aceites. En la estabilidad frente la oxidación y el descenso del punto de fusión, la mezcla de oleína de palma/canola (PO/CO fue mejor que las otras. Los termogramas del calorímetro diferencial de barrido (DSC referidos al comportamiento de fusión de las mezclas indican algunos nuevos polimorfismos de los triglicéridos. Este estudio podría ayudar a las empresas que elaboran aceites a encontrar los aceites económicamente más viables para cocinar, con buenas propiedades nutricionales, así como con unas propiedades f

7 CFR 989.16 - Blend.

Science.gov (United States)

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Blend. 989.16 Section 989.16 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... CALIFORNIA Order Regulating Handling Definitions § 989.16 Blend. Blend means to mix or commingle raisins. ...

Effect of Blending on the Composition and Acceptability of Blends of ...

African Journals Online (AJOL)

However the blend was found deficient in lysine, leucine, iso-leucine and phenylalanine when compared with the FAO recommendations for infants. Increased levels of pigeon pea in the blend also resulted in significant increases in potassium, phosphorus, sodium, magnesium and calcium. Similarly, increased levels of ...

Ionic liquids and their hosting by polymers for HT-PEMFC membranes

Energy Technology Data Exchange (ETDEWEB)

Hana, M.; Martinez, M.; Cointeaux, L.; Lepretre, J.C. [LEPMI-ELSA, PHELMA, UMR 5631, CNRS, Grenoble INP, UJF, Saint-Martin-d' Heres (France); Molmeret, Y.; El Kissi, N. [Laboratoire de Rheologie, UMR 5520 CNRS-INPG-UJF, ENSHMG, Grenoble (France); Teles, J.; Judeinstein, P. [Institut de Chimie Moleculaire et des Materiaux d' Orsay, CNRS 8182, Orsay (France); Iojoiu, C.; Sanchez, J.Y.

2010-10-15

The paper deals with proton-conducting ionic liquids (PCILs) for use, in combination with functional polymers, in membranes operating in high temperature PEMFC. Monoammoniums derived from monoamines and half-neutralised diamines were investigated in the form of triflates. Promising results were obtained with the half-neutralised diamine-based PCIL, its conduction being governed by both Grotthuss-like and vehicular mechanisms, the respective contributions of which depend on temperature. In addition, their blending with Nafion results in a distinct reinforcement of the membrane. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

ACOUSTIC EFFECTS ON BINARY AEROELASTICITY MODEL

Directory of Open Access Journals (Sweden)

Kok Hwa Yu

2011-10-01

Full Text Available Acoustics is the science concerned with the study of sound. The effects of sound on structures attract overwhelm interests and numerous studies were carried out in this particular area. Many of the preliminary investigations show that acoustic pressure produces significant influences on structures such as thin plate, membrane and also high-impedance medium like water (and other similar fluids. Thus, it is useful to investigate the structure response with the presence of acoustics on aircraft, especially on aircraft wings, tails and control surfaces which are vulnerable to flutter phenomena. The present paper describes the modeling of structural-acoustic interactions to simulate the external acoustic effect on binary flutter model. Here, the binary flutter model which illustrated as a rectangular wing is constructed using strip theory with simplified unsteady aerodynamics involving flap and pitch degree of freedom terms. The external acoustic excitation, on the other hand, is modeled using four-node quadrilateral isoparametric element via finite element approach. Both equations then carefully coupled and solved using eigenvalue solution. The mentioned approach is implemented in MATLAB and the outcome of the simulated result are later described, analyzed and illustrated in this paper.

Morphology stabilization of heterogeneous blends

International Nuclear Information System (INIS)

1980-01-01

A heterogeneous elastomer blend is described, consisting of at least two elastomer components which are cross-linkable by irradiation and having a stabilized morphology formed by subjecting the blend to high energy radiation to a point from below to slightly above the gel dose of the blend. (author)

Locally restricted blending of Blobtrees

NARCIS (Netherlands)

Groot, de Erwin; Wyvill, B.; Wetering, van de H.M.M.

2009-01-01

Blobtrees are volume representations particularly useful for models which require smooth blending. When blending is applied to two or more Blobtree models, extra volume will be created in between the two surfaces to form a smooth connection. Although it is easy to apply blending, it is hard to

Performance of Blended Learning in University Teaching:

Directory of Open Access Journals (Sweden)

Michael Reiss

2010-07-01

Full Text Available Blended learning as a combination of classroom teaching and e-learning has become a widely represented standard in employee and management development of companies. The exploratory survey “Blended Learning@University” conducted in 2008 investigated the integration of blended learning in higher education. The results of the survey show that the majority of participating academic teachers use blended learning in single courses, but not as a program of study and thus do not exploit the core performance potential of blended learning. According to the study, the main driver of blended learning performance is its embeddedness in higher education. Integrated blended programs of study deliver the best results. In blended learning, learning infrastructure (in terms of software, culture, skills, funding, content providing, etc. does not play the role of a performance driver but serves as an enabler for blended learning.

Physico-mechanical and structural properties of eggshell membrane gelatin- chitosan blend edible films

DEFF Research Database (Denmark)

Mohammadi, Reza; Mohammadifar, Mohammad Amin; Rouhi, Milad

2018-01-01

This study investigated the physico-mechanical and structural properties of composite edible films based on eggshell membrane gelatin (G) and chitosan (Ch) (75G:25Ch, 50G:50Ch, 25G:75Ch). The results demonstrated that the addition of Ch increased elongation at break significantly (p< 0.05), but r......This study investigated the physico-mechanical and structural properties of composite edible films based on eggshell membrane gelatin (G) and chitosan (Ch) (75G:25Ch, 50G:50Ch, 25G:75Ch). The results demonstrated that the addition of Ch increased elongation at break significantly (p... interactions introduced by the addition of chitosan to eggshell membrane gelatin as new resources could improve the films’ functional properties....

[Computer modeling the hydrostatic pressure characteristics of the membrane potential for polymeric membrane, separated non-homogeneous electrolyte solutions].

Science.gov (United States)

Slezak, Izabella H; Jasik-Slezak, Jolanta; Rogal, Mirosława; Slezak, Andrzej

2006-01-01

On the basis of model equation depending the membrane potential deltapsis, on mechanical pressure difference (deltaP), concentration polarization coefficient (zetas), concentration Rayleigh number (RC) and ratio concentration of solutions separated by membrane (Ch/Cl), the characteristics deltapsis = f(deltaP)zetas,RC,Ch/Cl for steady values of zetas, RC and Ch/Cl in single-membrane system were calculated. In this system neutral and isotropic polymeric membrane oriented in horizontal plane, the non-homogeneous binary electrolytic solutions of various concentrations were separated. Nonhomogeneity of solutions is results from creations of the concentration boundary layers on both sides of the membrane. Calculations were made for the case where on a one side of the membrane aqueous solution of NaCl at steady concentration 10(-3) mol x l(-1) (Cl) was placed and on the other aqueous solutions of NaCl at concentrations from 10(-3) mol x l(-1) to 2 x 10(-2) mol x l(-1) (Ch). Their densities were greater than NaCl solution's at 10(-3) mol x l(-1). It was shown that membrane potential depends on hydrodynamic state of a complex concentration boundary layer-membrane-concentration boundary layer, what is controlled by deltaP, Ch/Cl, RC and zetas.

Membranes of Polymers of Intrinsic Microporosity (PIM-1) Modified by Poly(ethylene glycol).

Science.gov (United States)

Bengtson, Gisela; Neumann, Silvio; Filiz, Volkan

2017-06-05

Until now, the leading polymer of intrinsic microporosity PIM-1 has become quite famous for its high membrane permeability for many gases in gas separation, linked, however, to a rather moderate selectivity. The combination with the hydrophilic and low permeable poly(ethylene glycol) (PEG) and poly(ethylene oxides) (PEO) should on the one hand reduce permeability, while on the other hand enhance selectivity, especially for the polar gas CO₂ by improving the hydrophilicity of the membranes. Four different paths to combine PIM-1 with PEG or poly(ethylene oxide) and poly(propylene oxide) (PPO) were studied: physically blending, quenching of polycondensation, synthesis of multiblock copolymers and synthesis of copolymers with PEO/PPO side chain. Blends and new, chemically linked polymers were successfully formed into free standing dense membranes and measured in single gas permeation of N₂, O₂, CO₂ and CH₄ by time lag method. As expected, permeability was lowered by any substantial addition of PEG/PEO/PPO regardless the manufacturing process and proportionally to the added amount. About 6 to 7 wt % of PEG/PEO/PPO added to PIM-1 halved permeability compared to PIM-1 membrane prepared under similar conditions. Consequently, selectivity from single gas measurements increased up to values of about 30 for CO₂/N₂ gas pair, a maximum of 18 for CO₂/CH₄ and 3.5 for O₂/N₂.

Development of cookies made with cocoyam, fermented sorghum and germinated pigeon pea flour blends using response surface methodology.

Science.gov (United States)

Okpala, Laura C; Okoli, Eric C

2014-10-01

Cookies were produced from blends of cocoyam, fermented sorghum and germinated pigeon pea flours. The study was carried out to evaluate the effects of varying the proportions of these components on the sensory and protein quality of the cookies. The sensory attributes studied were colour, taste, texture, crispness and general acceptability while the protein quality indices were biological value (BV) and net protein utilization (NPU). Mixture response surface methodology was used to model the sensory and protein quality with single, binary and ternary combinations of germinated pigeon pea, fermented sorghum and cocoyam flours. Results showed that BV and NPU of most of the cookies were above minimum acceptable levels. With the exception of cookies containing high levels of pigeon pea flour, cookies had acceptable sensory scores. Increase in pigeon pea flour resulted in increase in the BV and NPU. Regression equations suggested that the ternary blends produced the highest increase in all the sensory attributes (with the exception of colour).

Prediction of the viscosity of lubricating oil blends at any temperature

Energy Technology Data Exchange (ETDEWEB)

Diaz, R.M.; Bernardo, M.I.; Fernandez, A.M.; Folgueras, M.B. [University of Oviedo, Oveido (Spain). Dept. of Energy

1996-04-01

This paper discusses a method of predicting the viscosity of multicomponent base lubricating oil mixtures based on Andrade`s equation. The kinematic viscosity of three types of base lubricating oils and their binary and ternary mixtures were measured at different temperatures and the parameters of Andrade`s equation were calculated. The results obtained indicate that the Andrade parameters vary linearly with the mixture composition. From these linear equations, generalized mixing equations are derived which confirm the experimental results. By application of the mixing equations, a simple method is obtained for prediction of the viscosity of oil blends at any temperature from viscosity-temperature data of the oil components. The calculated viscosities gave an average absolute deviation of 10% over the temperature range 20-100{degree}C. 8 refs., 3 figs., 4 tabs.

Blended Learning over Two Decades

Science.gov (United States)

Zhonggen, Yu; Yuexiu, Zhejiang

2015-01-01

The 21st century has witnessed vast amounts of research into blended learning since the conception of online learning formed the possibility of blended learning in the early 1990s. The theme of this paper is blended learning in mainstream disciplinary communities. In particular, the paper reports on findings from the last two decades which looked…

Evaporation characteristics of ETBE-blended gasoline.

Science.gov (United States)

Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

2015-04-28

To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were developed. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaporation characteristics of ETBE-blended gasoline

International Nuclear Information System (INIS)

Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

2015-01-01

Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

Evaporation characteristics of ETBE-blended gasoline

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Katsuhiro, E-mail: okamoto@nrips.go.jp [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan); Hiramatsu, Muneyuki [Yamanashi Prefectural Police H.Q., 312-4 Kubonakajima, Isawa-cho, Usui, Yamanashi 406-0036 (Japan); Hino, Tomonori; Otake, Takuma [Metropolitan Police Department, 2-1-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8929 (Japan); Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan)

2015-04-28

Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

AKRO/SF: Blend System

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Blend was the system used by the NMFS Alaska Regional Office to monitor groundfish catch from 1991 until 2002. The Blend system combined data from industry...

High-Flux Carbon Molecular Sieve Membranes for Gas Separation.

Science.gov (United States)

Richter, Hannes; Voss, Hartwig; Kaltenborn, Nadine; Kämnitz, Susanne; Wollbrink, Alexander; Feldhoff, Armin; Caro, Jürgen; Roitsch, Stefan; Voigt, Ingolf

2017-06-26

Carbon membranes have great potential for highly selective and cost-efficient gas separation. Carbon is chemically stable and it is relative cheap. The controlled carbonization of a polymer coating on a porous ceramic support provides a 3D carbon material with molecular sieving permeation performance. The carbonization of the polymer blend gives turbostratic carbon domains of randomly stacked together sp 2 hybridized carbon sheets as well as sp 3 hybridized amorphous carbon. In the evaluation of the carbon molecular sieve membrane, hydrogen could be separated from propane with a selectivity of 10 000 with a hydrogen permeance of 5 m 3 (STP)/(m 2 hbar). Furthermore, by a post-synthesis oxidative treatment, the permeation fluxes are increased by widening the pores, and the molecular sieve carbon membrane is transformed from a molecular sieve carbon into a selective surface flow carbon membrane with adsorption controlled performance and becomes selective for carbon dioxide. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanomaterials for membrane fouling control: accomplishments and challenges.

Science.gov (United States)

Yang, Qian; Mi, Baoxia

2013-11-01

We report a review of recent research efforts on incorporating nanomaterials-including metal/metal oxide nanoparticles, carbon-based nanomaterials, and polymeric nanomaterials-into/onto membranes to improve membrane antifouling properties in biomedical or potentially medical-related applications. In general, nanomaterials can be incorporated into/onto a membrane by blending them into membrane fabricating materials or by attaching them to membrane surfaces via physical or chemical approaches. Overall, the fascinating, multifaceted properties (eg, high hydrophilicity, superparamagnetic properties, antibacterial properties, amenable functionality, strong hydration capability) of nanomaterials provide numerous novel strategies and unprecedented opportunities to fully mitigate membrane fouling. However, there are still challenges in achieving a broader adoption of nanomaterials in the membrane processes used for biomedical applications. Most of these challenges arise from the concerns over their long-term antifouling performance, hemocompatibility, and toxicity toward humans. Therefore, rigorous investigation is still needed before the adoption of some of these nanomaterials in biomedical applications, especially for those nanomaterials proposed to be used in the human body or in contact with living tissue/body fluids for a long period of time. Nevertheless, it is reasonable to predict that the service lifetime of membrane-based biomedical devices and implants will be prolonged significantly with the adoption of appropriate fouling control strategies. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Preparation and Properties of Poly (vinylidene fluoride)/poly(dimethylsiloxane) graft (poly(propylene oxide)-block-poly(ethylene oxide)) blend porous separators and corresponding electrolytes

International Nuclear Information System (INIS)

Li, Hao; Zhang, Hong; Liang, Zhi-Ying; Chen, Yue-Ming; Zhu, Bao-Ku; Zhu, Li-Ping

2014-01-01

Highlights: •This work aims exploring microporous PVDF separators for lithium ion batteries. •Comb structure polymer PDMS-g-(PPO-PEO) was used in PVDF blend separators. •The influence of polyether side chains on interfacial resistance was studied. -- Abstract: This work aims exploring the high performance porous separators that can be activated into gel electrolyte membranes for lithium ion batteries. A comb-like copolymer poly (dimethylsiloxane) graft poly (propylene oxide)-block-poly (ethylene oxide) (PDMS-g-(PPO-PEO)) was synthesized and blended with poly (vinylidene fluoride) (PVDF) to fabricate porous separators via a typical phase inversion process, and then the separators absorbed liquid electrolyte solution and formed into polymer electrolyte membranes. By measuring the composition, morphology and ion conductivity etc, the influence of PDMS-g-(PPO-PEO) on structure and properties of blend separators were discussed. Compared with pure PVDF separator with comparable porous structure, the adoption of PDMS-g-(PPO-PEO) decreased the crystallinity and increased the liquid electrolyte uptake and stability effectively. It was also found that the electrode/electrolyte interfacial resistance could be reduced greatly. The resulting electrolyte membrane using separator with PVDF/PDMS-g-(PPO-PEO) mass ratio in 8/2 exhibited highest ionic conductivity in 4.5 × 10 −3 S/cm at room temperature, while the electrochemical stability was up to 4.7 V (vs. Li/Li + ). Coin cells assembled with such separators also exhibited stable cycle performance and improved rate capabilities, especially when discharge rate higher than 0.5 C

Binary Polymer Brushes of Strongly Immiscible Polymers.

Science.gov (United States)

Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

2015-06-17

The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

Entanglement in miscible blends

Science.gov (United States)

Watanabe, Hiroshi

2010-03-01

The entanglement length Le of polymer chains (corresponding to the entanglement molecular weight Me) is not an intrinsic material parameter but changes with the interaction with surrounding chains. For miscible blends of cis-polyisoprene (PI) and poly(tert-butyl styrene) (PtBS), changes of Le on blending was examined. It turned out that the Le averaged over the number fractions of the Kuhn segments of the components (PI and PtBS) satisfactorily describes the viscoelastic behavior of pseudo-monodisperse blends in which the terminal relaxation time is the same for PI and PtBS.

Miscibility evolution of polycarbonate/polystyrene blends during compounding

DEFF Research Database (Denmark)

Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib

2002-01-01

The miscibility evolution of polycarbonate/polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, remelt blending in a twin-screw extruder and third melt blending in an injection molding machine, was investigated...... polymer in the other. The observed solubility strongly depends on blend composition and blending method. The T-g measurements showed maximum mutual solubility around 50/50 composition. The miscibility of PC/PS blended after the third stage (melt injection molding) was higher than that after the first...... by measuring their glass transition temperatures (T-g) and their specific heat increment (DeltaC(p)). Differential scanning calorimetry (DSC) was used to examine nine blend compositions. Shifts in glass transition temperature (T-g) of the two phases in melt-mixed PC/PS blends suggest partial miscibility of one...

Wound healing properties of PVA/starch/chitosan hydrogel membranes with nano Zinc oxide as antibacterial wound dressing material.

Science.gov (United States)

Baghaie, Shaghayegh; Khorasani, Mohammad T; Zarrabi, Ali; Moshtaghian, Jamal

2017-12-01

In this work, hydrogel membranes were developed based on poly vinyl alcohol (PVA), starch (St), and chitosan (Cs) hydrogels with nano Zinc oxide (nZnO). PVA/St/Cs/nZnO hydrogel membranes were prepared by freezing-thawing cycles, and the aqueous PVA/St solutions were prepared by dissolving PVA in distilled water. After the dissolution of PVA, starch was mixed, and the mixture was stirred. Then, chitosan powder was added into acetic acid, and the mixture was stirred to form a chitosan solution. Subsequently, Cs, St and PVA solutions were blended together to form a homogeneous PVA/St/Cs ternary blend solution. Measurement of Equilibrium Swelling Ratio (ESR), Water Vapor Transmission Test (WVTR), mechanical properties, scanning electron microscopy (SEM), MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay, antibacterial studies, in vivo wound healing effect and histopathology of the hydrogel membranes were then performed. The examination revealed that the hydrogel membranes were more effective as a wound dressing in the early stages of wound healing and that the gel could be used in topic applications requiring a large spectrum of antibacterial activity; namely, as a bandage for wound dressing.

Castor oil and commercial thermoplastic polyurethane membranes modified with polyaniline: a comparative study

Energy Technology Data Exchange (ETDEWEB)

Almeida Junior, Jose Humberto Santos; Meneguzzi, Alvaro; Ferreira, Carlos Arthur, E-mail: jhsajunior@globomail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegtre, RS (Brazil). Dept. de Engenharia de Materiais; Bertuol, Daniel Assumpcao [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Dept. de Engenharia Quimica; Amado, Franco Dani Rico [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologia

2013-11-01

The study of conducting polymeric membranes is decisive in some areas, as in fuel cells and electrodialysis. This work aims the study of membranes using conventional and conductive polymers blends. Two types of polyurethane were used as conventional polymers, commercial thermoplastic polyurethane and polyurethane synthesized from castor oil and 4-4-dicyclohexylmethane isocyanate. Two kinds of conducting polymers were used, polyaniline doped with organic acid and a self doped polyaniline. The polymers and the membranes were characterized by electrical conductivity, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The synthesis of the membranes produced was proper, featuring a complete reaction, analyzed by FTIR. The membranes also showed good mechanical properties and thermal stability ( Almost-Equal-To 220 Degree-Sign C). Among the membranes studied, the polyaniline doped with p-toluenesulphonic acid obtained higher thermal and viscoelastic properties. Thus they can be used in separation techniques using membranes. (author)

Graphene oxide doped ionic liquid ultrathin composite membranes for efficient CO2 capture

KAUST Repository

Karunakaran, Madhavan

2016-11-28

Advanced membrane systems with high flux and sufficient selectivity are required for industrial gas separation processes. In order to achieve high flux and high selectivity, the membrane material should be as thin as possible and it should have selective sieving channels and long term stability. This could be achieved by designing a three component material consisting of a blend of an ionic liquid and graphene oxide covered by a highly permeable low selective polymeric coating. By using a simple dip coating technique, we prepared high flux and CO selective ultrathin graphene oxide (GO)/ionic liquid membranes on a porous ultrafiltration support. The ultrathin composite membranes derived from GO/ionic liquid complex displays remarkable combinations of permeability (CO flux: 37 GPU) and selectivity (CO/N selectivity: 130) that surpass the upper bound of ionic liquid membranes for CO/N separation. Moreover, the membranes were stable when tested for 120 hours.

Effects of Blended-Cement Paste Chemical Composition Changes on Some Strength Gains of Blended-Mortars

Science.gov (United States)

Kirgiz, Mehmet Serkan

2014-01-01

Effects of chemical compositions changes of blended-cement pastes (BCPCCC) on some strength gains of blended cement mortars (BCMSG) were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC) were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP) or 6%, 20%, 21%, and 35% brick powder (BP) for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min). Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC) and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS) and flexural strengths (FS) of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2), sodium oxide (Na2O), and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2) at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM) in comparison with reference mortars (RM) at whole cure days as MP up to 6% or BP up to 35% was blended for cement. PMID:24587737

Effects of Blended-Cement Paste Chemical Composition Changes on Some Strength Gains of Blended-Mortars

Directory of Open Access Journals (Sweden)

Mehmet Serkan Kirgiz

2014-01-01

Full Text Available Effects of chemical compositions changes of blended-cement pastes (BCPCCC on some strength gains of blended cement mortars (BCMSG were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP or 6%, 20%, 21%, and 35% brick powder (BP for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min. Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS and flexural strengths (FS of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2, sodium oxide (Na2O, and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2 at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM in comparison with reference mortars (RM at whole cure days as MP up to 6% or BP up to 35% was blended for cement.

Introducing blended e-learning course design

DEFF Research Database (Denmark)

Gyamfi, Samuel Adu; Ryberg, Thomas

2012-01-01

In the face of diminishing education budgets in higher education, blended learning has been found to be a viable and effective approach to deliver high-quality, up-to-date, on-demand solutions to developing cross-curricular skills of undergraduates. However, research has also shown that blended...... learning solutions do not often live up to the potential of the approach or fail to produce the intended results because the students are not always equipped to handle the technical, psychological and organisational challenges of blended learning approaches. This project surveyed seventy-five first year...... the students’ e-readiness for an implementation of a blend-ed course design....

Development of more efficient and cheaper MEA's for PEM fuel cells; Membrane-electrode-assembly

Energy Technology Data Exchange (ETDEWEB)

Yde Andersen, S. (IRD Fuel Cell A/S, Svendborg (Denmark)); Nilsson, M.S. (Danish Power System Aps, Charlottenlund (Denmark)); Siu, A.; Plackett, D. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Dansk Polymer Center, Roskilde (Denmark)); Li, Q. (Technical Univ. of Denmark, Dept. of Chemistry, Kgs. Lyngby (Denmark))

2008-06-15

The project covered 5 main areas: 1) polymer and membranes; 2) electrocatalysts; 3) gas diffusion electrodes; 4) MEAs; and 5) evaluation techniques. For the polymers, by purification of monomers and optimizing parameters, high molecular weight polybenzimidazoles have been synthesized in batches of 50 g with good reproducibility. Based on the polymer, two types of new membranes have been prepared. One is the cross-linked (covalently and acid-base) PBI blend membranes. The blend membranes were systematically characterized and show excellent properties such as very high acid doping levels, conductivity, mechanical strength and durability. The other type is composite membranes based on PBI and nanoclay. Using the modified nanoclay, good dispersion and transparent composite membranes have been achieved. For catalyst preparation, the carbon supports have been modified with thermal treatment. Improved corrosion resistance was achieved with little sacrificing of the catalytic activity. High Pt loading catalysts were prepared, based on which high performance gas diffusion electrodes were fabricated. The performance target of both cathode and anode was achieved, as evaluated by the PTFE half cell tests. New gas diffusion layer (GDL) materials have been developed and tested in different MEA configurations. Significant performance improvement has been achieved with also potential to reduce the cost. Techniques for applying micro porous layers and catalyst layers have been optimized, including tape casting, spraying, and catalyst-coated membrane (CCM). Using the developed membranes and gas diffusion electrodes, membrane-electrode assemblies (MEAs) were fabricated for both single cell and stack tests. Selection of sealing materials and design of integrated gaskets have been made for both low and high temperature MEAs. Parameters for hot-pressing such as temperature, pressure and duration were systematically studied. 44 MEAs with an active area of 256 cm{sup 2} have been prepared

Pulsars in binary systems: probing binary stellar evolution and general relativity.

Science.gov (United States)

Stairs, Ingrid H

2004-04-23

Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.

Coalescence in PLA-PBAT blends under shear flow: Effects of blend preparation and PLA molecular weight

Energy Technology Data Exchange (ETDEWEB)

Nofar, M. [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4, Canada and CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Heuzey, M. C.; Carreau, P. J., E-mail: pierre.carreau@polymtl.ca [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4 (Canada); Kamal, M. R. [CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Randall, J. [NatureWorks LLC, 15305 Minnetonka Boulevard, Minnetonka, Minnesota 55345 (United States)

2016-07-15

Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s{sup −1} at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s{sup −1} induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.

Coalescence in PLA-PBAT blends under shear flow: Effects of blend preparation and PLA molecular weight

International Nuclear Information System (INIS)

Nofar, M.; Heuzey, M. C.; Carreau, P. J.; Kamal, M. R.; Randall, J.

2016-01-01

Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s"−"1 at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s"−"1 induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.

Morphology Evolution of Polycarbonate-Polystyrene Blends During Compounding

DEFF Research Database (Denmark)

Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib

2001-01-01

The morphology evolution of polycarbonate-polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, re-melt blending in a twin-screw extruder and tri-melt blending in an injection-moulding machine, was investigated using......-empirical model. The results show that the formation of co-continuous morphology strongly depends on blend composition and melt blending method, whereas the model prediction for phase inversion deviates from the experimental values. Further, we found that the initial mechanism of morphology evolution involves...... scanning electron microscopy (SEM) Co examine nine blend compositions. Blends were prepared at compositions where phase inversion was expected to occur according to model predictions. The experimental results were compared to the values of the point of phase inversion calculated with the semi...

Effective separation of propylene/propane binary mixtures by ZIF-8 membranes

KAUST Repository

Pan, Yichang; Li, Tao; Lestari, Gabriella; Lai, Zhiping

2012-01-01

The separation of propylene/propane mixtures is one of the most important but challenging processes in the petrochemical industry. A novel zeolitic imidazole framework (ZIF-8) membrane prepared by a facile hydrothermal seeded growth method showed

Organic non-volatile memories from ferroelectric phase separated blends

Science.gov (United States)

Asadi, Kamal; de Leeuw, Dago; de Boer, Bert; Blom, Paul

2009-03-01

Ferroelectric polarisation is an attractive physical property for non-volatile binary switching. The functionality of the targeted memory should be based on resistive switching. Conductivity and ferroelectricity however cannot be tuned independently. The challenge is to develop a storage medium in which the favourable properties of ferroelectrics such as bistability and non-volatility can be combined with the beneficial properties provided by semiconductors such as conductivity and rectification. In this contribution we present an integrated solution by blending semiconducting and ferroelectric polymers into phase separated networks. The polarisation field of the ferroelectric modulates the injection barrier at the semiconductor--metal contact. This combination allows for solution-processed non-volatile memory arrays with a simple cross-bar architecture that can be read-out non-destructively. Based on this general concept a non-volatile, reversible switchable Schottky diode with relatively fast programming time of shorter than 100 microseconds, long information retention time of longer than 10^ days, and high programming cycle endurance with non-destructive read-out is demonstrated.

Characterization of polyethersulfone-polyimide hollow fiber membranes by atomic force microscopy and contact angle goniometery

NARCIS (Netherlands)

Khulbe, K.C.; Feng, C.; Matsuura, T.; Kapantaidakis, G.; Wessling, Matthias; Koops, G.H.

2003-01-01

Asymmetric blend polyethersulfone-polyimide (PES-PI) hollow fiber membranes prepared at different air gap and used for gas separation are characterized by atomic force microscopy (inside and out side surfaces) and by measuring the contact angle of out side surface. The outer surface was entirely

Blended Learning Design

DEFF Research Database (Denmark)

Pedersen, Lise

2015-01-01

University College Lillebaelt has decided that 30 percent of all educational elements must be generated as blended learning by the end of the year 2015 as part of a modernization addressing following educational needs: 1. Blended learning can help match the expectations of the future students who...... learning. 4. Blended learning can contribute to supporting and improving efficiency of educational efforts. This can for instance be done through programmes for several classes by using video conferencing, allocating traditional face to face teaching to synchronous and asynchronous study activities produce...... digital materials which can be employed didactically and reused by the teachers. This can also mean that the particular competencies which teaches have in Svendborg can be used at other locations in UCL and disseminated to a larger group of students without further costs. Educational Innovation...

Nucleation in Polymers and Soft Matter

Science.gov (United States)

Xu, Xiaofei; Ting, Christina L.; Kusaka, Isamu; Wang, Zhen-Gang

2014-04-01

Nucleation is a ubiquitous phenomenon in many physical, chemical, and biological processes. In this review, we describe recent progress on the theoretical study of nucleation in polymeric fluids and soft matter, including binary mixtures (polymer blends, polymers in poor solvents, compressible polymer-small molecule mixtures), block copolymer melts, and lipid membranes. We discuss the methodological development for studying nucleation as well as novel insights and new physics obtained in the study of the nucleation behavior in these systems.

ULTRAFILTRATION AS PRETREATMENT OF REVERSE OSMOSIS: LOW FOULING ULTRAFILTRATION MEMBRANE PREPARED FROM POLYETHERSULFONE–AMPHIPHILIC BLOCK COPOLYMER BLEND

Directory of Open Access Journals (Sweden)

Heru Susanto

2012-02-01

Full Text Available This paper demonstrates the preparation of polyethersulfone (PES ultrafiltration (UF membranes via wet phase inversion method using either poly(ethylene oxide-b-poly(propylene oxide-b- poly(ethylene oxide (Pluronic®, Plu or polyethylene glycol (PEG as hydrophilic modifier. Their effects on membrane structure as well as the resulting membrane performance and their stability in membrane polymer matrix were systematically investigated. The investigated membrane characteristics include surface hydrophilicity (by contact angle, surface chemistry (by FTIR spectroscopy and water flux measurement. Visualization of membrane surface and cross section morphology was also done by scanning electron microscopy. The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of bovine serum albumin as the model system. The stability of additive was examined by incubating the membrane in water (40oC for up to 10 days. The results show that modification effects on membrane characteristic and low fouling behavior were clearly observed. Further, amphiphilic Pluronic generally showed better performance than PEG.   

Blended Learning: How Teachers Balance the Blend of Online and Classroom Components

Science.gov (United States)

Jeffrey, Lynn M.; Milne, John; Suddaby, Gordon

2014-01-01

Despite teacher resistance to the use of technology in education, blended learning has increased rapidly, driven by evidence of its advantages over either online or classroom teaching alone. However, blended learning courses still fail to maximize the benefits this format offers. Much research has been conducted on various aspects of this problem,…

Separation of methane-nitrogen mixtures using synthesis vertically aligned carbon nanotube membranes

Science.gov (United States)

Gilani, Neda; Daryan, Jafar Towfighi; Rashidi, Alimorad; Omidkhah, Mohammad Reza

2012-03-01

In this paper, capabilities of carbon nanotube (CNT) membranes fabricated in cylindrical pores of anodic aluminum oxide (AAO) substrate to separate the binary mixtures of CH4/N2 are studied experimentally. For this purpose, the permeability and selectivity of three CNT/AAO membranes with different growth time as 6 h, 12 h and 18 h are investigated. CNTs are grown vertically through holes of AAO with average pore diameter of 45 nm by chemical vapor deposition (CVD) of acetylene gas. CNT/AAO membranes with the same CNTs' outer diameters and different inner diameters are synthesized. The AAO are characterized by SEM analysis. In addition, SEM, TEM, BET N2 adsorption analysis and Raman spectroscopy are employed to characterize aligned CNTs. Study on permeability and selectivity of membranes for three binary mixtures of CH4/N2 showed that when the CNT inner diameters are 34 nm and 24 nm, viscous flow is the governing mechanism and insignificant selectivities of 1.2-1.24 are achieved. However, the membrane with CNT inner diameter and wall thickness of 8 nm and 16 nm respectively is considerably selective for CH4 over N2. It was also found that CH4 mole fraction in the feed and upstream feed pressure have major effect on permeability and selectivity. The membrane with 18 h synthesis time showed the selectivity is in the range of 1.8-3.85. The enhancement factor for N2 single gas diffusivity was also found to be about three times larger than that predicted by Knudsen diffusion model.

Trojan Binaries

Science.gov (United States)

Noll, K. S.

2017-12-01

The Jupiter Trojans, in the context of giant planet migration models, can be thought of as an extension of the small body populations found beyond Neptune in the Kuiper Belt. Binaries are a distinctive feature of small body populations in the Kuiper Belt with an especially high fraction apparent among the brightest Cold Classicals. The binary fraction, relative sizes, and separations in the dynamically excited populations (Scattered, Resonant) reflects processes that may have eroded a more abundant initial population. This trend continues in the Centaurs and Trojans where few binaries have been found. We review new evidence including a third resolved Trojan binary and lightcurve studies to understand how the Trojans are related to the small body populations that originated in the outer protoplanetary disk.

Thin films of polymer blends deposited by matrix-assisted pulsed laser evaporation: Effects of blending ratios

International Nuclear Information System (INIS)

Paun, Irina Alexandra; Ion, Valentin; Moldovan, Antoniu; Dinescu, Maria

2011-01-01

In this work, we show successful use of matrix-assisted pulsed laser evaporation (MAPLE) for obtaining thin films of PEG:PLGA blends, in the view of their use for controlled drug delivery. In particular, we investigate the influence of the blending ratios on the characteristics of the films. We show that the roughness of the polymeric films is affected by the ratio of each polymer within the blend. In addition, we perform Fourier transformed infrared spectroscopy (FTIR) measurements and we find that the intensities ratios of the infrared absorption bands of the two polymers are consistent with the blending ratios. Finally, we assess the optical constants of the polymeric films by spectroscopic ellipsometry (SE). We point out that the blending ratios exert an influence on the optical characteristics of the films and we validate the SE results by atomic force microscopy and UV-vis spectrophotometry. In all, we stress that the ratios in which the two polymers are blended have significant impact on the morphology, chemical structure and optical characteristics of the polymeric films deposited by MAPLE.

Preparation and performance of porous phase change polyethylene glycol/polyurethane membrane

International Nuclear Information System (INIS)

Ke Guizhen; Xie Huifang; Ruan Ruping; Yu Weidong

2010-01-01

Based on the theory of clotty porous phase change materials, the porous membrane was prepared with the blend of polyurethane (PU) and two polyethylene glycol (PEG) systems. Studied by scanning electron microscope (SEM), Fourier transform infrared (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and thermo-gravimetric (TG) tests, the morphology structure, chemical composition, crystalline morphology, phase change behaviors and thermal stability of porous phase change membrane were investigated. The results showed that the PU/PEG membrane had obvious porous structural feature, suitable transition temperature and high transition enthalpy. It is a flexible membrane with good energy storage function. When it is between solid and liquid transfer state in microcosms, the membrane can still keep solid shape in macroscopic state at high temperature during phase transition processing. It means that porous membrane PCM can be regarded as functional polymer. This method solved the problem of low working materials content in phase change textile. It succeeded in introducing the porous technology into functional textile's formation, and developed a new way to improve the phase change enthalpy largely for adjustable textile.

Emissions characteristics of higher alcohol/gasoline blends

International Nuclear Information System (INIS)

Gautam, M.; Martin, D.W.; Carder, D.

2000-01-01

An experimental investigation was conducted to determine the emissions characteristics of higher alcohols and gasoline (UTG96) blends. While lower alcohols (methanol and ethanol) have been used in blends with gasoline, very little work has been done or reported on higher alcohols (propanol, butanol and pentanol). Comparisons of emissions and fuel characteristics between higher alcohol/gasoline blends and neat gasoline were made to determine the advantages and disadvantages of blending higher alcohols with gasoline. All tests were conducted on a single-cylinder Waukesha Cooperative Fuel Research engine operating at steady state conditions and stoichiometric air-fuel (A/F) ratio. Emissions test were conducted at the optimum spark timing-knock limiting compression ratio combination for the particular blend being tested. The cycle emission [mass per unit time (g/h)] of CO, CO 2 and organic matter hydrocarbon equivalent (OMHCE) from the higher alcohol/gasoline blends were very similar to those from neat gasoline. Cycle emissions of NO x from the blends were higher than those from neat gasoline. However, for all the emissions species considered, the brake specific emissions (g/kW h) were significantly lower for the higher alcohol/gasoline blends than for neat gasoline. This was because the blends had greater resistance to knock and allowed higher compression ratios, which increased engine power output. The contribution of alcohols and aldehydes to the overall OMHCE emissions was found to be minimal. Cycle fuel consumption (g/h) of higher alcohol/gasoline blends was slightly higher than with neat gasoline due to the lower stoichiometric A/F ratios required by the blends. However, the brake specific fuel consumption (g/kW h) for the blends was significantly lower than that for neat gasoline. (Author)

Preparation and characterization of amphiphilic copolymer PVDF-g-PMABS and its application in improving hydrophilicity and protein fouling resistance of PVDF membrane

Science.gov (United States)

Chen, Fengtao; Shi, Xingxing; Chen, Xiaobing; Chen, Wenxing

2018-01-01

A facile strategy to improve the hydrophilicity and the antifouling properties of poly(vinylidene fluoride) (PVDF) membranes, a functional monomer of 4-methacrylamidobenzenesulfonic acid (MABS), was designed and synthesized through the amidation reaction between 2-methylacryloyl chloride and sulfanilic acid. Utilizing PVDF and the obtained MABS as reaction monomers, a novel amphiphilic copolymer was firstly prepared by radical polymerization method. The resulting PVDF-g-PMABS was used as a hydrophilic additive in the fabrication of PVDF porous membranes via immersion precipitation process. The surface chemical compositions and structure morphologies of as-prepared blend membranes (PVDF-g-PMABS/PVDF) were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. Contact angle measurement and cross-flow permeation test were employed to evaluate the hydrophilicity and antifouling properties of the membranes. It was found that the blend membrane with 4 wt.% PVDF-g-PMABS exhibited a noticeable pure water flux (136.34 L m-2 h-1) and a remarkable flux recovery ratio (FRR) of 98.60% in comparison with the pristine PVDF membrane (63.37 L m-2 h-1 and 38.67%, respectively). The enhanced performance was attributed to the synergetic effects of the strong hydrogen bonding force and the electrostatic repulsion of sulfonic groups against the protein foulants.

Sulfonated Poly(Ether Ether Ketone)/Functionalized Carbon Nanotube Composite Membrane for Vanadium Redox Flow Battery Applications

International Nuclear Information System (INIS)

Jia, Chuankun; Cheng, Yuanhang; Ling, Xiao; Wei, Guanjie; Liu, Jianguo; Yan, Chuanwei

2015-01-01

A novel sulfonated poly(ether ether ketone) (SPEEK) membrane embedded with the short-carboxylic multi-walled carbon nanotube (we name it as SPEEK/SCCT membrane) for vanadium redox flow battery (VRB) has been prepared with low capacity loss, low cost and high energy efficiency. The mechanical strength, vanadium ions permeability and performance of the membrane in the VRB single cell were characterized. Results showed that the SPEEK/SCCT membrane possessed low permeability of vanadium ions, accompanied by higher mechanical strength than the Nafion 212 membrane. The VRB single cell with SPEEK/SCCT membrane showed 7% higher coulombic efficiency (CE), 6% higher energy efficiency (EE) but lower capacity loss in comparison with the one with Nafion 212. The good cell performance, low capacity loss and high vanadium ions barrier properties of the blend membrane is of significant interest for VRB applications

Improvement of PET surface hydrophilicity and roughness through blending

Energy Technology Data Exchange (ETDEWEB)

Kolahchi, Ahmad Rezaei; Ajji, Abdellah; Carreau, Pierre J. [CREPEC, Chemical Engineering Department, Polytechnique Montreal, 2500 chemin de Polytechnique, Quebec, Montreal (Canada)

2015-05-22

Controlling the adhesion of the polymer surface is a key issue in surface science, since polymers have been a commonly used material for many years. The surface modification in this study includes two different aspects. One is to enhance the hydrophilicity and the other is to create the roughness on the PET film surface. In this study we developed a novel and simple approach to modify polyethylene terephthalate (PET) film surface through polymer blending in twin-screw extruder. One example described in the study uses polyethylene glycol (PEG) in polyethylene terephthalate (PET) host to modify a PET film surface. Low content of polystyrene (PS) as a third component was used in the system to increase the rate of migration of PEG to the surface of the film. Surface enrichment of PEG was observed at the polymer/air interface of the polymer film containing PET-PEG-PS whereas for the PET-PEG binary blend more PEG was distributed within the bulk of the sample. Furthermore, a novel method to create roughness at the PET film surface was proposed. In order to roughen the surface of PET film, a small amount of PKHH phenoxy resin to change PS/PET interfacial tension was used. The compatibility effect of PKHH causes the formation of smaller PS droplets, which were able to migrate more easily through PET matrix. Consequently, resulting in a locally elevated concentration of PS near the surface of the film. The local concentration of PS eventually reached a level where a co-continuous morphology occurred, resulting in theinstabilities on the surface of the film.

40 CFR 80.82 - Butane blending.

Science.gov (United States)

2010-07-01

... FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.82 Butane blending. A refiner for any refinery that produces gasoline by blending butane with conventional gasoline or reformulated gasoline or RBOB may meet... paragraph (b)(1) of this section, the refiner may: (i) Blend the butane with conventional gasoline, or...

Studies on improved integrated membrane-based chromatographic process for bioseparation

Science.gov (United States)

Xu, Yanke

To improve protein separation and purification directly from a fermentation broth, a novel membrane filtration-cum-chromatography device configuration having a relatively impermeable coated zone near the hollow fiber module outlet has been developed. The integrated membrane filtration-cum-chromatography unit packed with chromatographic beads on the shell side of the hollow fiber unit enjoys the advantages of both membrane filtration and chromatography; it allows one to load the chromatographic media directly from the fermentation broth or lysate and separate the adsorbed proteins through the subsequent elution step in a cyclic process. Interfacial polymerization was carried out to coat the bottom section of the hollow fiber membrane while leaving the rest of the hollow fiber membrane unaffected. Myoglobin (Mb), bovine serum albumin (BSA) and a-lactalbumin (a-LA) were used as model proteins in binary mixtures. Separation behaviors of binary protein mixtures were studied in devices using either an ultrafiltration (UF) membrane or a microfiltration (MF) membrane. Experimental results show that the breakthrough time and the protein loading capacities were dramatically improved after coating in both UF and MF modules. For a synthetic yeast fermentation broth feed, the Mb and a-LA elution profiles for the four consecutive cyclic runs were almost superimposable. Due to the lower transmembrane flux in this device plus the periodical washing-elution during the chromatographic separation, fouling was not a problem as it is in conventional microfiltration. A mathematical model describing the hydrodynamic and protein loading behaviors of the integrated device using UF membrane with a coated zone was developed. The simulation results for the breakthrough agree well with the experimental breakthrough curves. The optimal length of the coated zone was obtained from the simulation. A theoretical analysis of the protein mass transfer was performed using a diffusion-convection model

Development of high-performance blended cements

Science.gov (United States)

Wu, Zichao

2000-10-01

This thesis presents the development of high-performance blended cements from industrial by-products. To overcome the low-early strength of blended cements, several chemicals were studied as the activators for cement hydration. Sodium sulfate was discovered as the best activator. The blending proportions were optimized by Taguchi experimental design. The optimized blended cements containing up to 80% fly ash performed better than Type I cement in strength development and durability. Maintaining a constant cement content, concrete produced from the optimized blended cements had equal or higher strength and higher durability than that produced from Type I cement alone. The key for the activation mechanism was the reaction between added SO4 2- and Ca2+ dissolved from cement hydration products.

Self-Assembled Asymmetric Block Copolymer Membranes: Bridging the Gap from Ultra- to Nanofiltration

KAUST Repository

Yu, Haizhou

2015-09-21

The self-assembly of block copolymers is an emerging strategy to produce isoporous ultrafiltration membranes. However, thus far, it has not been possible to bridge the gap from ultra- to nanofiltration and decrease the pore size of self-assembled block copolymer membranes to below 5 nm without post-treatment. It is now reported that the self-assembly of blends of two chemically interacting copolymers can lead to highly porous membranes with pore diameters as small as 1.5 nm. The membrane containing an ultraporous, 60 nm thin separation layer can fully reject solutes with molecular weights of 600 g mol−1 in aqueous solutions with a water flux that is more than one order of magnitude higher than the permeance of commercial nanofiltration membranes. Simulations of the membrane formation process by dissipative particle dynamics (DPD) were used to explain the dramatic observed pore size reduction combined with an increase in water flux.

Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

Science.gov (United States)

Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

2017-09-01

We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

Phase behavior of binary polybutadiene copolymer mixtures as an example of weakly interacting polymers

CERN Document Server

Schwahn, D

2002-01-01

Binary blends of statistical polybutadiene copolymers of different vinyl content and molar volume were explored by small-angle neutron scattering. These samples represent the most simple class of statistical copolymer mixtures. In spite of this simplicity, changes in vinyl content, molar volume, and deuterium and hydrogen content of the chains give rise to strong effects; phase separation occurs from minus 230 C to more than plus 200 C and can even reverse from an enthalpically driven one at low temperatures to an entropically driven one at high temperatures. The entropic and enthalpic terms of the Flory-Huggins parameter as determined from the experiment are in excellent agreement with lattice cluster theory calculations. (orig.)

THE COMBUSTION CHARACTERISTICS OF LIGNITE BLENDS

Institute of Scientific and Technical Information of China (English)

Cheng Jun; Zhou Junhu; Cao Xinyu; Cen Kefa

2000-01-01

The combustion characteristics of lignite blends were studied with a thermogravimetric analyzer (t.g.a.), at constant heating rate.The characteristic temperatures were determined from the burning profiles.It was found that the characteristic times of combustion reaction moved forward, the ignition temperature dropped and the burnout efficiency slightly changed when blending lignites.The characteristic parameters of blends could not be predicted as a linear function of the average values of the individual lignites.when blending with less reactive coal, the ignition and burnout characteristics of lignite turned worse.

Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

International Nuclear Information System (INIS)

Rajabi, Hamid; Ghaemi, Negin; Madaeni, Sayed S.; Daraei, Parisa; Khadivi, Mohammad Ali; Falsafi, Monir

2014-01-01

Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling

Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

Energy Technology Data Exchange (ETDEWEB)

Rajabi, Hamid [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Department of Civil Engineering, Razi University, 67149 Kermanshah (Iran, Islamic Republic of); Ghaemi, Negin, E-mail: negin_ghaemi@kut.ac.ir [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Madaeni, Sayed S. [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Daraei, Parisa [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Khadivi, Mohammad Ali [Friedrich-Alexander University, Erlangen-Nuremberg, Egerland Strasse 3, D-91058 Erlangen (Germany); Falsafi, Monir [Department of Chemistry, Faculty of Science, Razi University, 67149 Kermanshah (Iran, Islamic Republic of)

2014-09-15

Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling.

Neutral wetting brush layers for block copolymer thin films using homopolymer blends processed at high temperatures

International Nuclear Information System (INIS)

Ceresoli, M; Palermo, M; Ferrarese Lupi, F; Seguini, G; Perego, M; Zuccheri, G; Phadatare, S D; Antonioli, D; Gianotti, V; Sparnacci, K; Laus, M

2015-01-01

Binary homopolymer blends of two hydroxyl-terminated polystyrene (PS-OH) and polymethylmethacrylate (PMMA-OH) homopolymers (Mn ∼ 16000 g mol"−"1) were grafted on SiO_2 substrates by high-temperature (T > 150 °C), short-time (t < 600 s) thermal treatments. The resulting brush layer was tested to screen preferential interactions of the SiO_2 substrate with the different symmetric and asymmetric PS-b-PMMA block copolymers deposited on top of the grafted molecules. By properly adjusting the blend composition and the processing parameters, an efficient surface neutralization path was identified, enabling the formation, in the block copolymer film, of homogeneous textures of lamellae or cylinders perpendicularly oriented with respect to the substrate. A critical interplay between the phase segregation of the homopolymer blends and their grafting process on the SiO_2 was observed. In fact, the polar SiO_2 is preferential for the PMMA-rich phase that forms a homogeneous layer on the substrate, while the PS-rich phase is located at the polymer-air interface. During the thermal treatment, phase segregation and grafting proceed simultaneously. Complete wetting of the PS rich phase on the PMMA rich phase leads to the formation of a PS/PMMA bilayer. In this case, the progressive diffusion of PS chains toward the polymer-SiO_2 interface during the thermal treatment allows tuning of the brush layer composition. (paper)

Binary Masking & Speech Intelligibility

DEFF Research Database (Denmark)

Boldt, Jesper

The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either experime......The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either...... experiments under ideal conditions or as experiments under more realistic conditions useful for real-life applications such as hearing aids. In the experiments under ideal conditions, the previously defined ideal binary mask is evaluated using hearing impaired listeners, and a novel binary mask -- the target...... binary mask -- is introduced. The target binary mask shows the same substantial increase in intelligibility as the ideal binary mask and is proposed as a new reference for binary masking. In the category of real-life applications, two new methods are proposed: a method for estimation of the ideal binary...

Structural characterization of HDPE/LLDPE blend-based nano composites obtained by different blending sequence

International Nuclear Information System (INIS)

Passador, Fabio R.; Ruvolo Filho, Adhemar; Pessan, Luiz A.

2011-01-01

The blending sequence affects the morphology formation of the nanocomposites. In this work, the blending sequences were explored to determine its influence in the rheological behavior of HDPE/LLDPE/OMMT nanocomposites. The nanocomposites were obtained by melt-intercalation using a mixture of LLDPE-g-MA and HDPE-g-MA as compatibilizer system in a torque rheometer at 180 deg C and five blending sequences were studied. The materials structures were characterized by wide angle X-ray diffraction (WAXD) and by rheological properties. The nanoclay's addition increased the shear viscosity at low shear rates, changing the behavior of HDPE/LLDPE matrix to a Bingham model behavior with an apparent yield stress. Intense interactions were obtained for the blending sequence where LLDPE and/or LLDPE-g-MA were first reinforced with organoclay since the intercalation process occurs preferentially in the amorphous phase. (author)

Interacting binary stars

CERN Document Server

Sahade, Jorge; Ter Haar, D

1978-01-01

Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

Hydrophilic nanofibers as new supports for thin film composite membranes for engineered osmosis.

Science.gov (United States)

Bui, Nhu-Ngoc; McCutcheon, Jeffrey R

2013-02-05

Engineered osmosis (e.g., forward osmosis, pressure-retarded osmosis, direct osmosis) has emerged as a new platform for applications to water production, sustainable energy, and resource recovery. The lack of an adequately designed membrane has been the major challenge that hinders engineered osmosis (EO) development. In this study, nanotechnology has been integrated with membrane science to build a next generation membrane for engineered osmosis. Specifically, hydrophilic nanofiber, fabricated from different blends of polyacrylonitrile and cellulose acetate via electrospinning, was found to be an effective support for EO thin film composite membranes due to its intrinsically wetted open pore structure with superior interconnectivity. The resulting composite membrane exhibits excellent permselectivity while also showing a reduced resistance to mass transfer that commonly impacts EO processes due to its thin, highly porous nanofiber support layer. Our best membrane exhibited a two to three times enhanced water flux and 90% reduction in salt passage when compared to a standard commercial FO membrane. Furthermore, our membrane exhibited one of the lowest structural parameters reported in the open literature. These results indicate that hydrophilic nanofiber supported thin film composite membranes have the potential to be a next generation membrane for engineered osmosis.

Chitosan/CNTs green nanocomposite membrane: Synthesis, swelling and polyaromatic hydrocarbons removal

International Nuclear Information System (INIS)

Bibi, Saira; Yasin, Tariq; Hassan, Safia; Riaz, Muhammad; Nawaz, Mohsan

2015-01-01

Carbon nanotubes (CNTs) were irradiated in air at 100 kGy under gamma radiations. The Raman spectroscopy of γ-treated CNTs showed distinctive changes in the absorption bands. The CNTs were mixed with blend of chitosan (Cs)/poly (vinyl alcohol) (PVA) and crosslinked with silane. The chemical reactions between the components affected the position and intensities of the infrared bands. Scanning electron micrograph of Cs/CNTs nanocomposite membrane showed the homogeneous dispersion of CNTs in the polymer matrix. The addition of CNTs lowered its swelling in water. Naphthalene (NAPH) was selected as a model compound and its removal was studied using HPLC technique. This membrane showed fast uptake of NAPH and 87% was removed from water within 30 min. The NAPH loaded membrane showed strong chemical interactions and cannot be desorbed. The fast uptake of PAHs and the green nature of this membrane made them suitable candidates for clean-up purposes. - Highlights: • Radiation modified CNTs and chitosan gave nanocomposite membranes. • This membrane showed hydrogel properties. • This membrane was used for the removal of naphthalene. • The green nature made them suitable candidates for clean-up purposes of PAH

Assessment of environmentally friendly fuel emissions from in-use vehicle exhaust: low-blend iso-stoichiometric GEM mixture as example.

Science.gov (United States)

Schifter, Isaac; Díaz-Gutiérrez, Luis; Rodríguez-Lara, René; González-Macías, Carmen; González-Macías, Uriel

2017-05-01

Gasoline-ethanol-methanol fuel blends were formulated with the same stoichiometric air-to-fuel ratio and volumetric energy concentration as any binary ethanol-gasoline blend. When the stoichiometric blends operated in a vehicle, the time period, injector voltage, and pressure for each fuel injection event in the engine corresponded to a given stoichiometric air-to-fuel ratio, and the load was essentially constant. Three low oxygen content iso-stoichiometric ternary gasoline-ethanol-methanol fuel blends were prepared, and the properties were compared with regular-type fuel without added oxygen. One of the ternary fuels was tested using a fleet of in-use vehicles for15 weeks and compared to neat gasoline without oxygenated compounds as a reference. Only a small number of publications have compared these ternary fuels in the same engine, and little data exist on the performance and emissions of in-use spark-ignition engines. The total hydrocarbon emissions observed was similar in both fuels, in addition to the calculated ozone forming potential of the tailpipe and evaporative emissions. In ozone non-attainment areas, the original purpose for oxygenate gasolines was to decrease carbon monoxide emissions. The results suggest that the strategy is less effective than expected because there still exist a great number of vehicles that have suffered the progressive deterioration of emissions and do not react to oxygenation, while new vehicles are equipped with sophisticated air/fuel control systems, and oxygenation does not improve combustion because the systems adjust the stoichiometric point, making it insensitive to the origin of the added excess oxygen (fuel or excess air). Graphical abstract Low level ternary blend of gasoline-ethanol-methanol were prepared with the same stoichiometric air-fuel ratio and volumetric energy concentration, based on the volumetric energy density of the pre-blended components. Exhaust and evaporative emissions was compared with a blend

HKUST-1 Membranes Anchored on Porous Substrate by Hetero MIL-110 Nanorod Array Seeds.

Science.gov (United States)

Mao, Yiyin; Cao, Wei; Li, Junwei; Sun, Luwei; Peng, Xinsheng

2013-09-02

Great anchors and seeds: Hetero-seeding growth processes and anchored nanorod arrays were successfully utilized in the synthesis of HKUST-1 membranes. These arrays were firmly anchored on porous substrates by using a MIL-110 nanorod array as both the anchor and seed. The resulting HKUST-1 membranes demonstrated good separation factors for binary gases exceeding the Knudson selectivity. Copyright © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Polymethylmethacrylate/Polyacrylonitrile Membranes via Centrifugal Spinning as Separator in Li-Ion Batteries

Directory of Open Access Journals (Sweden)

Meltem Yanilmaz

2015-04-01

Full Text Available Electrospun nanofiber membranes have been extensively studied as separators in Li-ion batteries due to their large porosity, unique pore structure, and high electrolyte uptake. However, the electrospinning process has some serious drawbacks, such as low spinning rate and high production cost. The centrifugal spinning technique can be used as a fast, cost-effective and safe technique to fabricate high-performance fiber-based separators. In this work, polymethylmethacrylate (PMMA/polyacrylonitrile (PAN membranes with different blend ratios were produced via centrifugal spinning and characterized by using different electrochemical techniques for use as separators in Li-ion batteries. Compared with commercial microporous polyolefin membrane, centrifugally-spun PMMA/PAN membranes had larger ionic conductivity, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. Centrifugally-spun PMMA/PAN membrane separators were assembled into Li/LiFePO4 cells and these cells delivered high capacities and exhibited good cycling performance at room temperature. In addition, cells using centrifugally-spun PMMA/PAN membrane separators showed superior C-rate performance compared to those using microporous polypropylene (PP membranes. It is, therefore, demonstrated that centrifugally-spun PMMA/PAN membranes are promising separator candidate for high-performance Li-ion batteries.

Poly(Lactic Acid) Hemodialysis Membranes with Poly(Lactic Acid)-block-Poly(2-Hydroxyethyl Methacrylate) Copolymer As Additive: Preparation, Characterization, and Performance.

Science.gov (United States)

Zhu, Lijing; Liu, Fu; Yu, Xuemin; Xue, Lixin

2015-08-19

Poly(lactic acid) (PLA) hemodialysis membranes with enhanced antifouling capability and hemocompatibility were developed using poly(lactic acid)-block-poly(2-hydroxyethyl methacrylate) (PLA-PHEMA) copolymers as the blending additive. PLA-PHEMA block copolymers were synthesized via reversible addition-fragmentation (RAFT) polymerization from aminolyzed PLA. Gel permeation chromatography (GPC) and (1)H-nuclear magnetic resonance ((1)H NMR) were applied to characterize the synthesized products. By blending PLA with the amphiphilic block copolymer, PLA/PLA-PHEMA membranes were prepared by nonsolvent induced phase separation (NIPS) method. Their chemistry and structure were characterized with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and atomic force microscopy (AFM). The results revealed that PLA/PLA-PHEMA membranes with high PLA-PHEMA contents exhibited enhanced hydrophilicity, water permeability, antifouling and hemocompatibility. Especially, when the PLA-PHEMA concentration was 15 wt %, the water flux of the modified membrane was about 236 L m(-2) h(-1). Its urea and creatinine clearance was more than 0.70 mL/min, lysozyme clearance was about 0.50 mL/min, BSA clearance was as less as 0.31 mL/min. All the results suggest that PLA-PHEMA copolymers had served as effective agents for optimizing the property of PLA-based membrane for hemodialysis applications.

Novel ion-exchange nanocomposite membrane containing in-situ formed FeOOH nanoparticles: Synthesis, characterization and transport properties

Energy Technology Data Exchange (ETDEWEB)

Heidary, Farhad; Kharat, Ali Nemati [University of Tehran, Tehran (Iran, Islamic Republic of); Khodabakhshi, Ali Reza [Faculty of Science, Arak University, Arak (Iran, Islamic Republic of)

2016-04-15

A new type of cation-exchange nanocomposite membrane was prepared via in-situ formation of FeOOH nanoparticles in a blend containing sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) and sulfonated polyvinylchloride by a simple one-step chemical method. Prepared nanocomposite membranes were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. The SEM images showed uniform dispersion of FeOOH nanoparticles throughout the polymeric matrices. The effect of additive loading on physicochemical and electrochemical properties of prepared cation-exchange nanocomposite membranes was studied. Various characterizations showed that the incorporation of different amounts of FeOOH nanoparticles into the basic membrane structure had a significant influence on the membrane performance and could improve the electrochemical properties.

Full Ionisation In Binary-Binary Encounters With Small Positive Energies

Science.gov (United States)

Sweatman, W. L.

2006-08-01

Interactions between binary stars and single stars and binary stars and other binary stars play a key role in the dynamics of a dense stellar system. Energy can be transferred between the internal dynamics of a binary and the larger scale dynamics of the interacting objects. Binaries can be destroyed and created by the interaction. In a binary-binary encounter, full ionisation occurs when both of the binary stars are destroyed in the interaction to create four single stars. This is only possible when the total energy of the system is positive. For very small energies the probability of this occurring is very low and it tends towards zero as the total energy tends towards zero. Here the case is considered for which all the stars have equal masses. An asymptotic power law is predicted relating the probability of full ionisation with the total energy when this latter quantity is small. The exponent, which is approximately 2.31, is compared with the results from numerical scattering experiments. The theoretical approach taken is similar to one used previously in the three-body problem. It makes use of the fact that the most dramatic changes in scale and energies of a few-body system occur when its components pass near to a central configuration. The position, and number, of these configurations is not known for the general four-body problem, however, with equal masses there are known to be exactly five different cases. Separate consideration and comparison of the properties of orbits close to each of these five central configurations enables the prediction of the form of the cross-section for full ionisation for the case of small positive total energy. This is the relation between total energy and the probability of total ionisation described above.

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

Energy Technology Data Exchange (ETDEWEB)

Kaltenegger, Lisa [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Haghighipour, Nader, E-mail: kaltenegger@mpia.de [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

2013-11-10

We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

International Nuclear Information System (INIS)

Kaltenegger, Lisa; Haghighipour, Nader

2013-01-01

We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886

Polymeric membranes modulate human keratinocyte differentiation in specific epidermal layers.

Science.gov (United States)

Salerno, Simona; Morelli, Sabrina; Giordano, Francesca; Gordano, Amalia; Bartolo, Loredana De

2016-10-01

In vitro models of human bioengineered skin substitutes are an alternative to animal experimentation for testing the effects and toxicity of drugs, cosmetics and pollutants. For the first time specific and distinct human epidermal strata were engineered by using membranes and keratinocytes. To this purpose, biodegradable membranes of chitosan (CHT), polycaprolactone (PCL) and a polymeric blend of CHT-PCL were prepared by phase-inversion technique and characterized in order to evaluate their morphological, physico-chemical and mechanical properties. The capability of membranes to modulate keratinocyte differentiation inducing specific interactions in epidermal membrane systems was investigated. The overall results demonstrated that the membrane properties strongly influence the cell morpho-functional behaviour of human keratinocytes, modulating their terminal differentiation, with the creation of specific epidermal strata or a fully proliferative epidermal multilayer system. In particular, human keratinocytes adhered on CHT and CHT-PCL membranes, forming the structure of the epidermal top layers, such as the corneum and granulosum strata, characterized by withdrawal or reduction from the cell cycle and cell proliferation. On the PCL membrane, keratinocytes developed an epidermal basal lamina, with high proliferating cells that stratified and migrated over time to form a complete differentiating epidermal multilayer system. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of nitrogen ion implantation on filtration of fluoride and cadmium using polysulfone/chitosan blend membranes

Energy Technology Data Exchange (ETDEWEB)

Wanichapichart, P., E-mail: pikul.v@psu.ac.th [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Songkhla 90110 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Bootluck, W. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Songkhla 90110 (Thailand); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2014-05-01

Composite membranes between polysulfone and biopolymer chitosan were produced with variations of the chitosan content and temperature during the phase inversion process. The lower chitosan content led to lower water permeability and smaller membrane cut off. When the temperature of the phase inversion process was reduced from 25 °C to 5 °C, membrane pores were further decreased from somewhat greater than 10 kDa to a value smaller than 2 kDa. After being implanted with N-ions of 50 keV to a fluence of 1 × 10{sup 15} ions/cm{sup 2}, the composite membranes showed an improvement in the rejection by about 15% for fluoride and 10% for cadmium. In addition, a slight increase in permeation flux was observed in the ion implanted membranes. Filtration tests using the N-ion implanted membranes showed that fluoride was rejected from 100 ppm NaF solution by 47% and the rejection was increased to 60% when 2.20 ppm underground water was filtered. In the case of cadmium, the rejection was increased from 80% to 90% as an effect of the N-ion implantation.

[Computer modeling the dependences of the membrane potential for polymeric membrane separated non-homogeneous electrolyte solutions on concentration Rayleigh number].

Science.gov (United States)

Slezak, Izabella H; Jasik-Slezak, Jolanta; Bilewicz-Wyrozumska, Teresa; Slezak, Andrzej

2006-01-01

On the basis of model equation describing the membrane potential delta psi(s) on concentration Rayleigh number (R(C)), mechanical pressure difference (deltaP), concentration polarization coefficient (zeta s) and ratio concentration of solutions separated by membrane (Ch/Cl), the characteristics delta psi(s) = f(Rc)(delta P, zeta s, Ch/Cl) for steady values of zeta s, R(C) and Ch/Cl in single-membrane system were calculated. In this system neutral and isotropic polymeric membrane oriented in horizontal plane, the non-homogeneous binary electrolytic solutions of various concentrations were separated. Nonhomogeneity of solutions is results from creations of the concentration boundary layers on both sides of the membrane. Calculations were made for the case where on a one side of the membrane aqueous solution of NaCl at steady concentration 10(-3) mol x l(-1) (Cl) was placed and on the other aqueous solutions of NaCl at concentrations from 10(-3) mol x l(-1) to 2 x 10(-2) mol x l(-1) (Ch). Their densities were greater than NaCl solution's at 10(-3) mol x l(-1). It was shown that membrane potential depends on hydrodynamic state of a complex concentration boundary layer-membrane-concentration boundary layer, what is controlled by deltaP, Ch/Cl, Rc and Zeta(s).

Flash nano-precipitation of polymer blends: a role for fluid flow?

Science.gov (United States)

Grundy, Lorena; Mason, Lachlan; Chergui, Jalel; Juric, Damir; Craster, Richard V.; Lee, Victoria; Prudhomme, Robert; Priestley, Rodney; Matar, Omar K.

2017-11-01

Porous structures can be formed by the controlled precipitation of polymer blends; ranging from porous matrices, with applications in membrane filtration, to porous nano-particles, with applications in catalysis, targeted drug delivery and emulsion stabilisation. Under a diffusive exchange of solvent for non-solvent, prevailing conditions favour the decomposition of polymer blends into multiple phases. Interestingly, dynamic structures can be `trapped' via vitrification prior to thermodynamic equilibrium. A promising mechanism for large-scale polymer processing is flash nano-precipitation (FNP). FNP particle formation has recently been modelled using spinodal decomposition theory, however the influence of fluid flow on structure formation is yet to be clarified. In this study, we couple a Navier-Stokes equation to a Cahn-Hilliard model of spinodal decomposition. The framework is implemented using Code BLUE, a massively scalable fluid dynamics solver, and applied to flows within confined impinging jet mixers. The present method is valid for a wide range of mixing timescales spanning FNP and conventional immersion precipitation processes. Results aid in the fabrication of nano-scale polymer particles with tuneable internal porosities. EPSRC, UK, MEMPHIS program Grant (EP/K003976/1), RAEng Research Chair (OKM), PETRONAS.

Derivation of the formula for the filtration coefficient by application of Poiseuille's law in membrane transport

Directory of Open Access Journals (Sweden)

Maria Jarzyńska

2011-01-01

Full Text Available On the basis of Kedem-Katchalsky equations a mathematical analysis of volume flow (Jv of a binary solution through a membrane (M is presented. Two cases of transport generators have been considered: hydrostatic (Δp as well as osmotic (Δπ pressure difference. Based on the Poiseuille's law we derive the formula for the membrane filtration coefficient (Lp which takes into account the membrane properties, kinetic viscosity and density of a solution flowing across the membrane. With use of this formula we have made model calculations of the filtration coefficient Lp and volume flow Jv for a polymer membrane in the case when the solutions on both sides of the membrane are mixed.

Preparation, Characterization and Performance Studies of Active PVDF Ultrafiltration-Surfactants Membranes Containing PVP as Additive

International Nuclear Information System (INIS)

Nur Izzah Md Fadilah; Abdul Rahman Hassan

2016-01-01

The role of surfactants in the formation of active Poly(vinylidene fluoride) (PVDF) ultrafiltration (AUF) membranes was studied. The effect combination of surfactants that are Sodium dodecyl sulfate (SDS)/ Tween 80 and Tween 80/ Triton X-100 formulations on performance and morphological structures were investigated for the first time. The influence of surfactants blends on the membrane pores was also examined. Experimental data showed that combination of Tween 80/ Triton X-100 give the highest BSA permeation flux with a value of 285.51 Lm -2 h -1 . With combination of SDS/ Tween 80, the AUF membrane showed the highest protein rejection up to 93 % and 79 % for Bovine Serum Albumin (BSA) and Egg Albumin (EA), respectively. Moreover, membranes characterization demonstrated that the addition of SDS/ Tween 80 and Tween 80/ Triton X-100 were found to affect the performance, surface morphologies and membrane pores of AUF PVDF membranes. (author)

Novel polyvinyl alcohol-bioglass 45S5 based composite nanofibrous membranes as bone scaffolds

International Nuclear Information System (INIS)

Shankhwar, Nisha; Kumar, Manishekhar; Mandal, Biman B.; Srinivasan, A.

2016-01-01

Composite nanofibrous membranes based on sol-gel derived 45SiO 2 24.5CaO 24.5 Na 2 O 6 P 2 O 5 (bioglass, BG) and 43SiO 2 24.5CaO 24.5 Na 2 O 6 P 2 O 5 2Fe 2 O 3 (magnetic bioglass, MBG) blended with polyvinyl alcohol (PVA) have been electrospun. These low cost membranes were mostly amorphous in structure with minor crystalline (sodium calcium phosphate) precipitates. All membranes were biodegradable. Among these, the composites exhibited higher tensile strength, better proliferation of human osteosarcoma MG63 cells and higher alkaline phosphatase enzyme activity than the bare PVA membrane, indicating their potential in bone tissue engineering. The magnetic PVA-MBG scaffold was also found to be a promising candidate for magnetic hyperthermia application. - Highlights: • Electrospun low-cost PVA-45S5 bioglass (BG) nanofibrous membranes • PVA-BG membranes containing 2 wt.% Fe 2 O 3 exhibit spontaneous magnetization. • BG fillers strongly enhanced mechanical strength and bioresponse of membranes. • Membranes show promise for bone scaffold and hyperthermia applications.

Selectivity of Direct Methanol Fuel Cell Membranes

Directory of Open Access Journals (Sweden)

Antonino S. Aricò

2015-11-01

Full Text Available Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK, new generation perfluorosulfonic acid (PFSA systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC. The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2. This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115.

Selectivity of Direct Methanol Fuel Cell Membranes.

Science.gov (United States)

Aricò, Antonino S; Sebastian, David; Schuster, Michael; Bauer, Bernd; D'Urso, Claudia; Lufrano, Francesco; Baglio, Vincenzo

2015-11-24

Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion(®) were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate-PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA) was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC). The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA) was higher than the benchmark Nafion(®) 115-based MEA (77 mW·cm(-2) vs. 64 mW·cm(-2)). This result was due to a lower methanol crossover (47 mA·cm(-2) equivalent current density for s-PEEK vs. 120 mA·cm(-2) for Nafion(®) 115 at 60 °C as recorded at OCV with 2 M methanol) and a suitable area specific resistance (0.15 Ohm cm² for s-PEEK vs. 0.22 Ohm cm² for Nafion(®) 115).

Polyethylene/hydrophilic polymer blends for biomedical applications.

Science.gov (United States)

Brynda, E; Houska, M; Novikova, S P; Dobrova, N B

1987-01-01

Polyethylene blends with poly(2-hydroxyethyl methacrylate) [poly(HEMA)] or poly(2,3-dihydroxypropyl methacrylate) [poly(DHPMA)] were prepared by swelling polyethylene with HEMA or 2,3-epoxypropyl methacrylate (EPMA) and by polymerization of the respective monomers. Poly(EPMA) in blends was hydrolysed to poly(DHPMA) with acetic acid. The blends had similar surface and bulk compositions. Swelling with water and surface wettability were proportional to the content of the hydrophilic component; at the same content the polyethylene/poly(DHPMA) blends appeared more hydrophilic than those of polyethylene/poly(HEMA). Thrombus formation in contact with blood examined ex vivo and in vivo was considerably slower on the blends than on unmodified polyethylene. The tests indicated optima in composition; the best biological response was achieved with the blends containing about 14% poly(HEMA) or 16% poly(DHPMA).

HEU to LEU conversion and blending facility: Metal blending alternative to produce LEU oxide for disposal

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-09-01

US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. The nuclear material is converted to a form more proliferation- resistant than the original form. Blending HEU (highly enriched uranium) with less-enriched uranium to form LEU has been proposed as a disposition option. Five technologies are being assessed for blending HEU. This document provides data to be used in environmental impact analysis for the HEU-LEU disposition option that uses metal blending with an oxide waste product. It is divided into: mission and assumptions, conversion and blending facility descriptions, process descriptions and requirements, resource needs, employment needs, waste and emissions from plant, hazards discussion, and intersite transportation.

HEU to LEU conversion and blending facility: Metal blending alternative to produce LEU oxide for disposal

International Nuclear Information System (INIS)

1995-09-01

US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. The nuclear material is converted to a form more proliferation- resistant than the original form. Blending HEU (highly enriched uranium) with less-enriched uranium to form LEU has been proposed as a disposition option. Five technologies are being assessed for blending HEU. This document provides data to be used in environmental impact analysis for the HEU-LEU disposition option that uses metal blending with an oxide waste product. It is divided into: mission and assumptions, conversion and blending facility descriptions, process descriptions and requirements, resource needs, employment needs, waste and emissions from plant, hazards discussion, and intersite transportation

Preparation and Characterization of Soluble Eggshell Membrane Protein/PLGA Electro spun Nano fibers for Guided Tissue Regeneration Membrane

International Nuclear Information System (INIS)

Jia, J.; Liu, G.; Duan, Y.; Guo, Z.; Yu, J.

2012-01-01

Guided tissue regeneration (GTR) is a widely used method in periodontal therapy, which involves the placement of a barrier membrane to exclude migration of epithelium and ensure repopulation of periodontal ligament cells. The objective of this study is to prepare and evaluate a new type of soluble eggshell membrane protein (SEP)/poly (lactic-co-glycolic acid) (PLGA) nano fibers using electro spinning method for GTR membrane application. SEP/PLGA nano fibers were successfully prepared with various blending ratios. The morphology, chemical composition, surface wettability, and mechanical properties of the nano fibers were characterized using scanning electron microscopy (SEM), contact angle measurement, Fourier transform-infrared spectroscopy (FTIR), and a universal testing machine. L-929 fibroblast cells were used to evaluate the biocompatibility of SEP/PLGA nano fibers and investigate the interaction between cells and nano fibers. Results showed that the SEP/PLGA electro spun membrane was composed of uniform, bead-free nano fibers, which formed an interconnected porous network structure. Mechanical property of SEP has been greatly improved by the addition of PLGA. The biological study results showed that SEP/PLGA nano fibers could enhance cell attachment, spreading, and proliferation. The study indicated the potential of SEP/PLGA nano fibers for GTR application and provided a basis for future optimization

HEU to LEU conversion and blending facility: UNH blending alternative to produce LEU oxide for disposal

International Nuclear Information System (INIS)

1995-09-01

The United States Department of Energy (DOE) is examining options for the disposition of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. Disposition is a process of use or disposal of material that results in the material being converted to a form that is substantially and inherently more proliferation-resistant than is the original form. Examining options for increasing the proliferation resistance of highly enriched uranium (HEU) is part of this effort. This report provides data to be used in the environmental impact analysis for the uranyl nitrate hexahydrate blending option to produce oxide for disposal. This the Conversion and Blending Facility (CBF) alternative will have two missions (1) convert HEU materials into HEU uranyl nitrate (UNH) and (2) blend the HEU uranyl nitrate with depleted and natural assay uranyl nitrate to produce an oxide that can be stored until an acceptable disposal approach is available. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal

HEU to LEU conversion and blending facility: UNH blending alternative to produce LEU oxide for disposal

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-09-01

The United States Department of Energy (DOE) is examining options for the disposition of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. Disposition is a process of use or disposal of material that results in the material being converted to a form that is substantially and inherently more proliferation-resistant than is the original form. Examining options for increasing the proliferation resistance of highly enriched uranium (HEU) is part of this effort. This report provides data to be used in the environmental impact analysis for the uranyl nitrate hexahydrate blending option to produce oxide for disposal. This the Conversion and Blending Facility (CBF) alternative will have two missions (1) convert HEU materials into HEU uranyl nitrate (UNH) and (2) blend the HEU uranyl nitrate with depleted and natural assay uranyl nitrate to produce an oxide that can be stored until an acceptable disposal approach is available. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal.

Chitosan/CNTs green nanocomposite membrane: synthesis, swelling and polyaromatic hydrocarbons removal.

Science.gov (United States)

Bibi, Saira; Yasin, Tariq; Hassan, Safia; Riaz, Muhammad; Nawaz, Mohsan

2015-01-01

Carbon nanotubes (CNTs) were irradiated in air at 100 kGy under gamma radiations. The Raman spectroscopy of γ-treated CNTs showed distinctive changes in the absorption bands. The CNTs were mixed with blend of chitosan (Cs)/poly (vinyl alcohol) (PVA) and crosslinked with silane. The chemical reactions between the components affected the position and intensities of the infrared bands. Scanning electron micrograph of Cs/CNTs nanocomposite membrane showed the homogeneous dispersion of CNTs in the polymer matrix. The addition of CNTs lowered its swelling in water. Naphthalene (NAPH) was selected as a model compound and its removal was studied using HPLC technique. This membrane showed fast uptake of NAPH and 87% was removed from water within 30 min. The NAPH loaded membrane showed strong chemical interactions and cannot be desorbed. The fast uptake of PAHs and the green nature of this membrane made them suitable candidates for clean-up purposes. Copyright © 2014 Elsevier B.V. All rights reserved.

Anisotropic membranes for gas separation

Science.gov (United States)

Gollan, Arye Z.

1987-01-01

A gas separation membrane has a dense separating layer about 10,000 Angstroms or less thick and a porous support layer 10 to 400 microns thick that is an integral unit with gradually and continuously decreasing pore size from the base of the support layer to the surface of the thin separating layer and is made from a casting solution comprising ethyl cellulose and ethyl cellulose-based blends, typically greater than 47.5 ethoxyl content ethyl cellulose blended with compatible second polymers, such as nitrocellulose. The polymer content of the casting solution is from about 10% to about 35% by weight of the total solution with up to about 50% of this polymer weight a compatible second polymer to the ethyl cellulose in a volatile solvent such as isopropanol, methylacetate, methanol, ethanol, and acetone. Typical nonsolvents for the casting solutions include water and formamide. The casting solution is cast in air from about zero to 10 seconds to allow the volatile solvent to evaporate and then quenched in a coagulation bath, typically water, at a temperature of 7.degree.-25.degree. C. and then air dried at ambient temperature, typically 10.degree.-30.degree. C.

Interacting binaries

CERN Document Server

Shore, S N; van den Heuvel, EPJ

1994-01-01

This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.