Suresh Jewrajka - Academia.edu (original) (raw)
Papers by Suresh Jewrajka
Zenodo (CERN European Organization for Nuclear Research), 2005
Atom transfer radical polymerization (ATRP) of acrylamide was carried out in a glycerol-water (I ... more Atom transfer radical polymerization (ATRP) of acrylamide was carried out in a glycerol-water (I : I v/v) medium with 2-halopropionamide initiators, CuX (X = Cl, Br)/N,N,N~NN'N"-hexamethyltriethylenetetraamine (HMTETA) catalyst, CuX 2 /HMTETA (20 mol% of CuX/HMTETA) and excess alkali halide (ca. 0.2-I M) additives. The first-order kinetic plots for the disappearance of monomer were linear when either LiCl (0.2 or I M) (or both LiCI (I M) and CuC1 2 / HMTETA (20 mol% of CuCI/HMTETA) were added into the system, to start with. However, in all the cases molecular weights do not increase with conversion. This signifies the uncontrolled nature of polymerization. These results suggest that CuX 2 /HMTETA is a poor deactivator as far as the ATRP of acrylamide is concerned.
Journal of Materials Chemistry A, 2020
Correction for ‘Multifunctional amines enable the formation of polyamide nanofilm composite ultra... more Correction for ‘Multifunctional amines enable the formation of polyamide nanofilm composite ultrafiltration and nanofiltration membranes with modulated charge and performance’ by Jaladhi S. Trivedi et al., J. Mater. Chem. A, 2018, 6, 20242–20253, DOI: 10.1039/C8TA07841F.
RSC Advances, 2020
Correction for ‘Sustainable process for the preparation of potassium sulfate by electrodialysis a... more Correction for ‘Sustainable process for the preparation of potassium sulfate by electrodialysis and its concentration and purification by a nanofiltration process’ by Jaladhi S. Trivedi et al., RSC Adv., 2016, 6, 71807–71817, DOI: 10.1039/C6RA14303B.
Journal of Materials Chemistry B, 2019
Highly stable PEGylated Au NPs with low grafting density exhibit significant effect towards azide... more Highly stable PEGylated Au NPs with low grafting density exhibit significant effect towards azide–alkyne click cycloaddition and Michael addition reactions leading to rapid formation of injectable hydrogels and biologically relevant macromolecules.
Journal of Materials Chemistry A, 2018
Controlled diffusion of multifunctional amines towards the interface facilitates formation of sup... more Controlled diffusion of multifunctional amines towards the interface facilitates formation of supported ultrafiltration to nanofiltration membranes with modulated charge and performance.
ACS Applied Bio Materials, 2018
Amphiphilic conetwork (APCN) gels suffer from lack of direct injectability due to use of organic ... more Amphiphilic conetwork (APCN) gels suffer from lack of direct injectability due to use of organic solvent, prolonged crosslinking/polymerization process and immiscibility between hydrophilic and hydrophobic prepolymers. On the basis of prepolymers compatibility and polarity, we report the use of an advanced prepolymer liquid system for in situ construction of APCN gels. Solid elastic poly(ethylene glycol)linked-poly(ε-caprolactone)-linked-poly(2-dimethylaminoethyl)methacrylate (PEG-l-PCL-l-PDMA) APCN gels were formed upon addition of an appropriate amount of PDMA diluted in nonreactive sacrificial liquid PEG into a compatible blend of activated halide terminated PEG and PCL liquids. Compatibility among the prepolymers allowed favorable gelation. The polarity of the prepolymer liquid greatly influenced the gelation time. PEG-l-PCL-l-PDMA APCN gels were cytocompatible/ biodegradable and showed storage modulus in the range of 50−200 kPa and bioadhesive strength of 40−90 kPa. The fluorescence experiments showed that the hydrophobic probe, pyrene was distributed in both hydrophilic and hydrophobic phases of the APCN gels. These APCNs exhibited sustained release of hydrophobic and hydrophilic drugs. Effects of polarity, composition, and molecular weight of the liquid prepolymers on the gelation time, rheological property, and swelling behavior of the APCN gels have been investigated in details.
![Research paper thumbnail of Dually crosslinked injectable hydrogels of poly(ethylene glycol) and poly[(2-dimethylamino)ethyl methacrylate]-b-poly(N-isopropyl acrylamide) as a wound healing promoter](https://attachments.academia-assets.com/115987491/thumbnails/1.jpg)
](Journal of Materials Chemistry B, 2017
PEG-based dually crosslinked injectable hydrogels have been developed through extremely simple ch... more PEG-based dually crosslinked injectable hydrogels have been developed through extremely simple chemistry which avoids use of small molecular weight crosslinker, formation of by-products and involved low heat change. The hydrogels are useful for wound healing and soft tissue regeneration.
RSC Advances, 2016
A sustainable approach for the production of high purity potassium fertilizer (K2SO4) is highly n... more A sustainable approach for the production of high purity potassium fertilizer (K2SO4) is highly needed to cope with the food crisis.
ACS Applied Materials & Interfaces, 2016
In this study, we prepared poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG)/sodium chloride (N... more In this study, we prepared poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG)/sodium chloride (NaCl) blends by melt blending with a triple-screw dynamic extruder. The effects of PEG on the thermal property, mechanical property, and morphology of blends were investigated in detail. It was found that the incorporation of PEG and NaCl significantly improved the crystallization rate, elongation at break, surface adhesion, and reduced viscoelasticity of PLA. The blends were further batch-foamed at different temperatures with supercritical carbon dioxide to study the foaming properties. The results of PLA/PEG/NaCl (50 : 10 : 40 wt %) composites after foaming and particle leaching revealed that an interconnected bimodal porous scaffold with the highest porosity of 89% could be achieved. Furthermore, the addition of PEG can significantly reduce the water contact angle so as to enhance the wetting ability of the scaffolds. V
RSC Advances, 2015
One step synthesis of terpolymer-based cation exchange membrane for water desalination via electr... more One step synthesis of terpolymer-based cation exchange membrane for water desalination via electrodialysis.
Journal of Materials Chemistry B, 2013
The size distribution of the octadecyl rhodamine-6G (5.0 x 10-5 M) in waterethanol (4:1, v/v) media.
Journal of Materials Chemistry A, 2014
ABSTRACT We report the preparation of a novel cross-linked anion exchange membrane (AEM) from pol... more ABSTRACT We report the preparation of a novel cross-linked anion exchange membrane (AEM) from poly(acrylonitrile)-co-poly(2-dimethylamino)ethyl methacrylate (PAN-co-PDMA) copolymer by quaternizing the DMA moieties followed by cross-linking of –CN groups. This process avoids the use of the carcinogenic reagent, chloromethyl ether (CME) which is widely employed for the chloromethylation reaction in the preparation of AEMs. Key parameters were evaluated via electrodialysis (ED) during water purification and revealed that a copolymer containing 28 wt% PDMA possesses all the required properties of a high performance AEM, such as, reasonable water uptake (21%), good ion-exchange capacity (IEC = 1.30 m eq g−1), high ionic conductivity (Km = 2.22 mS cm−1), a high transport number (t− = 0.88) and good mechanical properties (9.2 MPa of tensile stress at break and 2.4 Kg cm−2 of burst strength in the water wet state). The AEM was directly tested in an ED unit in the recirculation mode by varying the concentration of the NaCl feed and the applied potential, showing a current efficiency as high as 80%. Such combination of physical and electrochemical properties of the membrane is attributed to its co-continuous morphology and its low degree of phase separation as confirmed by swelling, differential scanning calorimetry, the homogeneous distribution of oppositely charged dye and by the transparency of the membrane in both the dry and swelled states.
J. Mater. Chem. A, 2014
ABSTRACT We report the preparation of a new type of anion exchange membrane (AEM) from a random t... more ABSTRACT We report the preparation of a new type of anion exchange membrane (AEM) from a random terpolymer of poly n-butyl acrylate (PnBA), polyacrylonitrile (PAN) and poly(2-dimethyl aminoethyl)methacrylate (PDMA) through quaternization and cross-linking. Moderate amounts of hydrophobic and soft PnBA (ca. 18 wt%) in the terpolymer considerably influenced the electrochemical properties and desalination performance of the membrane. Standardization experiments revealed that a membrane (AEM-2) prepared from a terpolymer containing 18 wt% PnBA, 50 wt% PAN and 32 wt% PDMA exhibited low power consumption (W) (0.66–0.95 kW h kg−1) and high current efficiency (CE) (94–96%) at an applied potential of 1.5–2 volts per cell pair during the desalination of water (containing 2000 mg L−1 NaCl) via electrodialysis (ED). On the other hand, membranes prepared from the bi-component PAN-co-PDMA with a similar PDMA content (28–34 wt%) exhibited a relatively higher W (0.94–1.32 kW h kg−1) and lower CE (68–80%) under similar experimental conditions compared to AEM-2. The remarkable effect of hydrophobic PnBA on AEM-2 performance is attributed to the nanophase separation of quaternized PAN-co-PDMA domains, low degree of water uptake (12%) along with the absence of freezing bound water in the membrane. Rapid desalination (low W) with high CE by five pairs of alternative AEM-2 and standard cation exchange membrane in the ED unit (13 × 5 cm2) shows promise for the development of en energy efficient ED unit.
Polymer Composites, 2011
Jewrajka, SK and Haldar, S.(2011), Amphiphilic poly (acrylonitrile-co-acrylic acid)/silver nanoco... more Jewrajka, SK and Haldar, S.(2011), Amphiphilic poly (acrylonitrile-co-acrylic acid)/silver nanocomposite additives for the preparation of antibiofouling membranes with improved properties. Polymer Composites. doi: 10.1002/pc. 21218
Polymer Composites, 2009
ABSTRACT Three types of silver/polymer nanocomposite films were prepared: (1) silver/polymethyl m... more ABSTRACT Three types of silver/polymer nanocomposite films were prepared: (1) silver/polymethyl methacrylate, (2) silver/polystyrene, and (3) silver/polyt-butyl methacrylate by mixing colloidal solution of functionalized Ag nanoparticles with solution of pre-made polymers. The nanoparticles are randomly dispersed into the matrices. The desired surface functionality of Ag nanoparticle was achieved by using specific amphiphilic block copolymer (specific hydrophobic block part) as stabilizer. The stability of nanoparticles in these host hydrophobic polymer matrices was determined after annealing the nanocomposite films at high temperature. The nanoparticles remained stable and no agglomeration occurred upon annealing up to 120°C. Up to 20 wt% of block copolymer stabilized Ag nanoparticles (11% Ag) was successfully loaded in the polymer matrix. Such a dispersion of Ag nanoparticles into a hydrophobic polymer matrix significantly enhances the mechanical properties of the nanocomposite films. The storage and loss modulus increase with increasing Ag nanoparticles content. Compared with a polymer matrix, the polymer/Ag nanocomposites film (containing 0.65% of Ag) prepared by this method displayed storage modulus that are up to 130% higher. This is attributed to the high surface area of the polymer coated Ag nanoparticles in the polymer matrix and van der Waal's attraction force between surface of Ag nanoparticles (polymer brush) and host polymer matrix. Comparison of thermal properties of polymer and polymer/Ag nanocomposite films showed that the thermal stability of nanocomposites increases by about 20°C. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Journal of Polymer Science Part A: Polymer Chemistry, 2006
ABSTRACT The synthesis of polymer-matrix-compatible amphiphilic gold (Au) nano-particles with wel... more ABSTRACT The synthesis of polymer-matrix-compatible amphiphilic gold (Au) nano-particles with well-defined triblock polymer poly[2-(N,N-dimethylamino)ethyl methacrylate]-b-poly(methyl methacrylate)-b-poly[2-(N,N-dimethylamino)ethyl methaerylate] and diblock polymers poly(methyl methacrylate)-b-poly[2-(NN-dimethylamino)ethyl methacrylate], polystyrene-b-poly[2-(N,N-dimethylamino)ethyl methacrylate], and poly (t-butyl methacrylate)-b-poly[2-(N,N-dimethylamino)ethyl methacrylate in water and in aqueous tetrahydrofuran (tetrahydrofuran/H2O = 20:1 v/v) at room temperature is reported. All these amphiphilic block copolymers were synthesized with atom transfer radical polymerization. The variations of the position of the plasmon resonance band and the core diameter of such block copolymer functionalized An particles with the variation of the surface functionality, solvent, and molecular weight of the hydrophobic and hydrophilic parts of the block copolymers were systematically studied. Different types of polymer-Au nanocomposite films [poly(methyl methacrylate)-Au, poly(t-butyl methacrylate)-Au, polystyrene-Au, poly(vinyl alcohol)-Au, and poly(vinyl pyrrolidone)-Au] were prepared through the blending of appropriate functionalized Au nanoparticles with the respective polymer matrices {e.g., blending poly[2-(N,N-dimethylamino)ethyl methaerylate]-b-poly(methyl methacrylate)-b-poly[2-(N,N-dimethylamino)ethyl methacrylate] stabilized Au with the poly(methyl methacrylate)matrix only}. The compatibility of specific block copolymer modified Au nanoparticles with a specific homopolymer matrix was determined by a combination of ultraviolet-visible spectroscopy, transmission electron microscopy, and differential scanning calorimetry analyses. The facile formation of polymer-Au nanocomposites with a specific block copolymer stabilized Au particle was attributed to the good compatibility of block copolymer coated Au particles with a specific polymer matrix. (c) 2006 Wiley Periodicals, Inc.
Journal of Polymer Science Part A: Polymer Chemistry, 2009
Novel segmented polyurea elastomers containing soft polyisobutylene (PIB) segments were synthesiz... more Novel segmented polyurea elastomers containing soft polyisobutylene (PIB) segments were synthesized and characterized. The key ingredient, primary amine‐telechelic PIB oligomers (NH2‐PIB‐NH2) with number average molecular weights of 2500 and 6200 g/mol were synthesized. PIB‐based polyureas were prepared by using various aliphatic diisocyanates and diamine chain extenders with hard segment contents between 9.5 and 46.5% by weight. All copolymers displayed microphase morphologies as determined by dynamic mechanical analysis. Tensile strengths of nonchain‐extended and chain‐extended polyureas showed a linear dependence on the urea hard segment content. PIB‐based polyureas prepared with NH2‐PIB‐NH2 of Mn = 2500 g/mol, 4,4′‐methylendbis(cyclohexylisocyantate), and 1,6‐diaminohexane containing 45% hard segment exhibited 19.5 MPa tensile strength which rose to 23 MPa upon annealing at 150 °C for 12 h. With increasing hard segment content, elongation at break decreased from ∼ 450% to a plat...
Journal of Polymer Science Part A: Polymer Chemistry, 2009
The design, synthesis, characterization, and structure–property behavior of polyureas containing ... more The design, synthesis, characterization, and structure–property behavior of polyureas containing novel soft segments of mixed polyisobutylene (PIB)/poly(tetramethylene oxide) (PTMO) chains and conventional hard segments is presented. Modest amounts (12%) of PTMO in the soft PIB phase significantly increase both the tensile strength and elongation of the polyureas. These polyureas exhibit not only oxidative/hydrolytic stabilities far superior to Bionate® and Elast‐Eon® considered the most oxidatively stable polyurethanes on the market but also display mechanical properties (29 MPa tensile strength and 200% elongation) approaching those of conventional thermoplastic polyurethanes. The surfaces of these polyureas are covered/protected by PIB segments, which will lead to excellent biocompatibility. Our results demonstrate that the PTMO segments facilitate stress transfer from the continuous mixed soft phase to the dispersed hard phase, which strengthens and flexibilizes PIB‐based polyur...
Journal of Membrane Science, 2014
ABSTRACT We report a novel approach for in situPEGylation of thin film composite (TFC) reverse os... more ABSTRACT We report a novel approach for in situPEGylation of thin film composite (TFC) reverse osmosis (RO) membrane for sustained performance. The approach was based on use of end-functionalized polyethylene glycol (MPD-PEG-MPD or MeO-PEG-MPD) with end groups structure resembling the structure of m-phenylenediamine (MPD), commonly used forpreparation of TFC membrane.Michael addition reaction between MPD and acrylate-terminated-polyethylene glycol (AA-PEG-AA or MeO-PEG-AA) produces such type of end-functionality for further use in interfacial polymerization (IFP) with the conventionally used trimesoylchloride (TMC). PEGylated TFC membranes exhibited muchsuperior antifouling property during water desalination in presence of fouling agent (protein) compared to non-PEGylated TFC membrane. The best results were obtained with the membranes prepared by addition of 0.25 to 0.5% (w/v) of AA-PEG-AA or MeO-PEG-AA to the MPD solution (2% w/v in water) for Michael addition reaction prior to IFP with TMC (0.125% w/v) in as much as the antifouling property was enhanced and the performance (salt rejection efficiency and flux) remained almost unaffected. TFC membranes were characterized by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), contact angle(θ), scanning electron microscope (SEM), atomic force microscope (AFM) and CHN analyses. The incorporated PEG remained stable in the polyamide network and is mainly attributed to the participation of both MPD and MPD-PEG-MPD or PEG-MPD in the IFP process.
Zenodo (CERN European Organization for Nuclear Research), 2005
Atom transfer radical polymerization (ATRP) of acrylamide was carried out in a glycerol-water (I ... more Atom transfer radical polymerization (ATRP) of acrylamide was carried out in a glycerol-water (I : I v/v) medium with 2-halopropionamide initiators, CuX (X = Cl, Br)/N,N,N~NN'N"-hexamethyltriethylenetetraamine (HMTETA) catalyst, CuX 2 /HMTETA (20 mol% of CuX/HMTETA) and excess alkali halide (ca. 0.2-I M) additives. The first-order kinetic plots for the disappearance of monomer were linear when either LiCl (0.2 or I M) (or both LiCI (I M) and CuC1 2 / HMTETA (20 mol% of CuCI/HMTETA) were added into the system, to start with. However, in all the cases molecular weights do not increase with conversion. This signifies the uncontrolled nature of polymerization. These results suggest that CuX 2 /HMTETA is a poor deactivator as far as the ATRP of acrylamide is concerned.
Journal of Materials Chemistry A, 2020
Correction for ‘Multifunctional amines enable the formation of polyamide nanofilm composite ultra... more Correction for ‘Multifunctional amines enable the formation of polyamide nanofilm composite ultrafiltration and nanofiltration membranes with modulated charge and performance’ by Jaladhi S. Trivedi et al., J. Mater. Chem. A, 2018, 6, 20242–20253, DOI: 10.1039/C8TA07841F.
RSC Advances, 2020
Correction for ‘Sustainable process for the preparation of potassium sulfate by electrodialysis a... more Correction for ‘Sustainable process for the preparation of potassium sulfate by electrodialysis and its concentration and purification by a nanofiltration process’ by Jaladhi S. Trivedi et al., RSC Adv., 2016, 6, 71807–71817, DOI: 10.1039/C6RA14303B.
Journal of Materials Chemistry B, 2019
Highly stable PEGylated Au NPs with low grafting density exhibit significant effect towards azide... more Highly stable PEGylated Au NPs with low grafting density exhibit significant effect towards azide–alkyne click cycloaddition and Michael addition reactions leading to rapid formation of injectable hydrogels and biologically relevant macromolecules.
Journal of Materials Chemistry A, 2018
Controlled diffusion of multifunctional amines towards the interface facilitates formation of sup... more Controlled diffusion of multifunctional amines towards the interface facilitates formation of supported ultrafiltration to nanofiltration membranes with modulated charge and performance.
ACS Applied Bio Materials, 2018
Amphiphilic conetwork (APCN) gels suffer from lack of direct injectability due to use of organic ... more Amphiphilic conetwork (APCN) gels suffer from lack of direct injectability due to use of organic solvent, prolonged crosslinking/polymerization process and immiscibility between hydrophilic and hydrophobic prepolymers. On the basis of prepolymers compatibility and polarity, we report the use of an advanced prepolymer liquid system for in situ construction of APCN gels. Solid elastic poly(ethylene glycol)linked-poly(ε-caprolactone)-linked-poly(2-dimethylaminoethyl)methacrylate (PEG-l-PCL-l-PDMA) APCN gels were formed upon addition of an appropriate amount of PDMA diluted in nonreactive sacrificial liquid PEG into a compatible blend of activated halide terminated PEG and PCL liquids. Compatibility among the prepolymers allowed favorable gelation. The polarity of the prepolymer liquid greatly influenced the gelation time. PEG-l-PCL-l-PDMA APCN gels were cytocompatible/ biodegradable and showed storage modulus in the range of 50−200 kPa and bioadhesive strength of 40−90 kPa. The fluorescence experiments showed that the hydrophobic probe, pyrene was distributed in both hydrophilic and hydrophobic phases of the APCN gels. These APCNs exhibited sustained release of hydrophobic and hydrophilic drugs. Effects of polarity, composition, and molecular weight of the liquid prepolymers on the gelation time, rheological property, and swelling behavior of the APCN gels have been investigated in details.
Journal of Materials Chemistry B, 2017
PEG-based dually crosslinked injectable hydrogels have been developed through extremely simple ch... more PEG-based dually crosslinked injectable hydrogels have been developed through extremely simple chemistry which avoids use of small molecular weight crosslinker, formation of by-products and involved low heat change. The hydrogels are useful for wound healing and soft tissue regeneration.
RSC Advances, 2016
A sustainable approach for the production of high purity potassium fertilizer (K2SO4) is highly n... more A sustainable approach for the production of high purity potassium fertilizer (K2SO4) is highly needed to cope with the food crisis.
ACS Applied Materials & Interfaces, 2016
In this study, we prepared poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG)/sodium chloride (N... more In this study, we prepared poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG)/sodium chloride (NaCl) blends by melt blending with a triple-screw dynamic extruder. The effects of PEG on the thermal property, mechanical property, and morphology of blends were investigated in detail. It was found that the incorporation of PEG and NaCl significantly improved the crystallization rate, elongation at break, surface adhesion, and reduced viscoelasticity of PLA. The blends were further batch-foamed at different temperatures with supercritical carbon dioxide to study the foaming properties. The results of PLA/PEG/NaCl (50 : 10 : 40 wt %) composites after foaming and particle leaching revealed that an interconnected bimodal porous scaffold with the highest porosity of 89% could be achieved. Furthermore, the addition of PEG can significantly reduce the water contact angle so as to enhance the wetting ability of the scaffolds. V
RSC Advances, 2015
One step synthesis of terpolymer-based cation exchange membrane for water desalination via electr... more One step synthesis of terpolymer-based cation exchange membrane for water desalination via electrodialysis.
Journal of Materials Chemistry B, 2013
The size distribution of the octadecyl rhodamine-6G (5.0 x 10-5 M) in waterethanol (4:1, v/v) media.
Journal of Materials Chemistry A, 2014
ABSTRACT We report the preparation of a novel cross-linked anion exchange membrane (AEM) from pol... more ABSTRACT We report the preparation of a novel cross-linked anion exchange membrane (AEM) from poly(acrylonitrile)-co-poly(2-dimethylamino)ethyl methacrylate (PAN-co-PDMA) copolymer by quaternizing the DMA moieties followed by cross-linking of –CN groups. This process avoids the use of the carcinogenic reagent, chloromethyl ether (CME) which is widely employed for the chloromethylation reaction in the preparation of AEMs. Key parameters were evaluated via electrodialysis (ED) during water purification and revealed that a copolymer containing 28 wt% PDMA possesses all the required properties of a high performance AEM, such as, reasonable water uptake (21%), good ion-exchange capacity (IEC = 1.30 m eq g−1), high ionic conductivity (Km = 2.22 mS cm−1), a high transport number (t− = 0.88) and good mechanical properties (9.2 MPa of tensile stress at break and 2.4 Kg cm−2 of burst strength in the water wet state). The AEM was directly tested in an ED unit in the recirculation mode by varying the concentration of the NaCl feed and the applied potential, showing a current efficiency as high as 80%. Such combination of physical and electrochemical properties of the membrane is attributed to its co-continuous morphology and its low degree of phase separation as confirmed by swelling, differential scanning calorimetry, the homogeneous distribution of oppositely charged dye and by the transparency of the membrane in both the dry and swelled states.
J. Mater. Chem. A, 2014
ABSTRACT We report the preparation of a new type of anion exchange membrane (AEM) from a random t... more ABSTRACT We report the preparation of a new type of anion exchange membrane (AEM) from a random terpolymer of poly n-butyl acrylate (PnBA), polyacrylonitrile (PAN) and poly(2-dimethyl aminoethyl)methacrylate (PDMA) through quaternization and cross-linking. Moderate amounts of hydrophobic and soft PnBA (ca. 18 wt%) in the terpolymer considerably influenced the electrochemical properties and desalination performance of the membrane. Standardization experiments revealed that a membrane (AEM-2) prepared from a terpolymer containing 18 wt% PnBA, 50 wt% PAN and 32 wt% PDMA exhibited low power consumption (W) (0.66–0.95 kW h kg−1) and high current efficiency (CE) (94–96%) at an applied potential of 1.5–2 volts per cell pair during the desalination of water (containing 2000 mg L−1 NaCl) via electrodialysis (ED). On the other hand, membranes prepared from the bi-component PAN-co-PDMA with a similar PDMA content (28–34 wt%) exhibited a relatively higher W (0.94–1.32 kW h kg−1) and lower CE (68–80%) under similar experimental conditions compared to AEM-2. The remarkable effect of hydrophobic PnBA on AEM-2 performance is attributed to the nanophase separation of quaternized PAN-co-PDMA domains, low degree of water uptake (12%) along with the absence of freezing bound water in the membrane. Rapid desalination (low W) with high CE by five pairs of alternative AEM-2 and standard cation exchange membrane in the ED unit (13 × 5 cm2) shows promise for the development of en energy efficient ED unit.
Polymer Composites, 2011
Jewrajka, SK and Haldar, S.(2011), Amphiphilic poly (acrylonitrile-co-acrylic acid)/silver nanoco... more Jewrajka, SK and Haldar, S.(2011), Amphiphilic poly (acrylonitrile-co-acrylic acid)/silver nanocomposite additives for the preparation of antibiofouling membranes with improved properties. Polymer Composites. doi: 10.1002/pc. 21218
Polymer Composites, 2009
ABSTRACT Three types of silver/polymer nanocomposite films were prepared: (1) silver/polymethyl m... more ABSTRACT Three types of silver/polymer nanocomposite films were prepared: (1) silver/polymethyl methacrylate, (2) silver/polystyrene, and (3) silver/polyt-butyl methacrylate by mixing colloidal solution of functionalized Ag nanoparticles with solution of pre-made polymers. The nanoparticles are randomly dispersed into the matrices. The desired surface functionality of Ag nanoparticle was achieved by using specific amphiphilic block copolymer (specific hydrophobic block part) as stabilizer. The stability of nanoparticles in these host hydrophobic polymer matrices was determined after annealing the nanocomposite films at high temperature. The nanoparticles remained stable and no agglomeration occurred upon annealing up to 120°C. Up to 20 wt% of block copolymer stabilized Ag nanoparticles (11% Ag) was successfully loaded in the polymer matrix. Such a dispersion of Ag nanoparticles into a hydrophobic polymer matrix significantly enhances the mechanical properties of the nanocomposite films. The storage and loss modulus increase with increasing Ag nanoparticles content. Compared with a polymer matrix, the polymer/Ag nanocomposites film (containing 0.65% of Ag) prepared by this method displayed storage modulus that are up to 130% higher. This is attributed to the high surface area of the polymer coated Ag nanoparticles in the polymer matrix and van der Waal's attraction force between surface of Ag nanoparticles (polymer brush) and host polymer matrix. Comparison of thermal properties of polymer and polymer/Ag nanocomposite films showed that the thermal stability of nanocomposites increases by about 20°C. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Journal of Polymer Science Part A: Polymer Chemistry, 2006
ABSTRACT The synthesis of polymer-matrix-compatible amphiphilic gold (Au) nano-particles with wel... more ABSTRACT The synthesis of polymer-matrix-compatible amphiphilic gold (Au) nano-particles with well-defined triblock polymer poly[2-(N,N-dimethylamino)ethyl methacrylate]-b-poly(methyl methacrylate)-b-poly[2-(N,N-dimethylamino)ethyl methaerylate] and diblock polymers poly(methyl methacrylate)-b-poly[2-(NN-dimethylamino)ethyl methacrylate], polystyrene-b-poly[2-(N,N-dimethylamino)ethyl methacrylate], and poly (t-butyl methacrylate)-b-poly[2-(N,N-dimethylamino)ethyl methacrylate in water and in aqueous tetrahydrofuran (tetrahydrofuran/H2O = 20:1 v/v) at room temperature is reported. All these amphiphilic block copolymers were synthesized with atom transfer radical polymerization. The variations of the position of the plasmon resonance band and the core diameter of such block copolymer functionalized An particles with the variation of the surface functionality, solvent, and molecular weight of the hydrophobic and hydrophilic parts of the block copolymers were systematically studied. Different types of polymer-Au nanocomposite films [poly(methyl methacrylate)-Au, poly(t-butyl methacrylate)-Au, polystyrene-Au, poly(vinyl alcohol)-Au, and poly(vinyl pyrrolidone)-Au] were prepared through the blending of appropriate functionalized Au nanoparticles with the respective polymer matrices {e.g., blending poly[2-(N,N-dimethylamino)ethyl methaerylate]-b-poly(methyl methacrylate)-b-poly[2-(N,N-dimethylamino)ethyl methacrylate] stabilized Au with the poly(methyl methacrylate)matrix only}. The compatibility of specific block copolymer modified Au nanoparticles with a specific homopolymer matrix was determined by a combination of ultraviolet-visible spectroscopy, transmission electron microscopy, and differential scanning calorimetry analyses. The facile formation of polymer-Au nanocomposites with a specific block copolymer stabilized Au particle was attributed to the good compatibility of block copolymer coated Au particles with a specific polymer matrix. (c) 2006 Wiley Periodicals, Inc.
Journal of Polymer Science Part A: Polymer Chemistry, 2009
Novel segmented polyurea elastomers containing soft polyisobutylene (PIB) segments were synthesiz... more Novel segmented polyurea elastomers containing soft polyisobutylene (PIB) segments were synthesized and characterized. The key ingredient, primary amine‐telechelic PIB oligomers (NH2‐PIB‐NH2) with number average molecular weights of 2500 and 6200 g/mol were synthesized. PIB‐based polyureas were prepared by using various aliphatic diisocyanates and diamine chain extenders with hard segment contents between 9.5 and 46.5% by weight. All copolymers displayed microphase morphologies as determined by dynamic mechanical analysis. Tensile strengths of nonchain‐extended and chain‐extended polyureas showed a linear dependence on the urea hard segment content. PIB‐based polyureas prepared with NH2‐PIB‐NH2 of Mn = 2500 g/mol, 4,4′‐methylendbis(cyclohexylisocyantate), and 1,6‐diaminohexane containing 45% hard segment exhibited 19.5 MPa tensile strength which rose to 23 MPa upon annealing at 150 °C for 12 h. With increasing hard segment content, elongation at break decreased from ∼ 450% to a plat...
Journal of Polymer Science Part A: Polymer Chemistry, 2009
The design, synthesis, characterization, and structure–property behavior of polyureas containing ... more The design, synthesis, characterization, and structure–property behavior of polyureas containing novel soft segments of mixed polyisobutylene (PIB)/poly(tetramethylene oxide) (PTMO) chains and conventional hard segments is presented. Modest amounts (12%) of PTMO in the soft PIB phase significantly increase both the tensile strength and elongation of the polyureas. These polyureas exhibit not only oxidative/hydrolytic stabilities far superior to Bionate® and Elast‐Eon® considered the most oxidatively stable polyurethanes on the market but also display mechanical properties (29 MPa tensile strength and 200% elongation) approaching those of conventional thermoplastic polyurethanes. The surfaces of these polyureas are covered/protected by PIB segments, which will lead to excellent biocompatibility. Our results demonstrate that the PTMO segments facilitate stress transfer from the continuous mixed soft phase to the dispersed hard phase, which strengthens and flexibilizes PIB‐based polyur...
Journal of Membrane Science, 2014
ABSTRACT We report a novel approach for in situPEGylation of thin film composite (TFC) reverse os... more ABSTRACT We report a novel approach for in situPEGylation of thin film composite (TFC) reverse osmosis (RO) membrane for sustained performance. The approach was based on use of end-functionalized polyethylene glycol (MPD-PEG-MPD or MeO-PEG-MPD) with end groups structure resembling the structure of m-phenylenediamine (MPD), commonly used forpreparation of TFC membrane.Michael addition reaction between MPD and acrylate-terminated-polyethylene glycol (AA-PEG-AA or MeO-PEG-AA) produces such type of end-functionality for further use in interfacial polymerization (IFP) with the conventionally used trimesoylchloride (TMC). PEGylated TFC membranes exhibited muchsuperior antifouling property during water desalination in presence of fouling agent (protein) compared to non-PEGylated TFC membrane. The best results were obtained with the membranes prepared by addition of 0.25 to 0.5% (w/v) of AA-PEG-AA or MeO-PEG-AA to the MPD solution (2% w/v in water) for Michael addition reaction prior to IFP with TMC (0.125% w/v) in as much as the antifouling property was enhanced and the performance (salt rejection efficiency and flux) remained almost unaffected. TFC membranes were characterized by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), contact angle(θ), scanning electron microscope (SEM), atomic force microscope (AFM) and CHN analyses. The incorporated PEG remained stable in the polyamide network and is mainly attributed to the participation of both MPD and MPD-PEG-MPD or PEG-MPD in the IFP process.