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Deepak Srivastava - One of the best experts on this subject based on the ideXlab platform.
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effect of glycidyl methacrylate gma content on thermal and mechanical properties of ternary blend systems based on cardanol based Vinyl Ester Resin styrene and glycidyl methacrylate
Progress in Organic Coatings, 2014Co-Authors: Minakshi Sultania Garg, Deepak SrivastavaAbstract:Abstract Cardanol-based Vinyl Ester Resin (CVER) was prepared by reacting indigenously synthesized cardanol-based epoxidized novolac Resin (CENR) with methacrylic acid (MA) in the presence of triphenylphosphine as catalyst. Five samples of cardanol-based Vinyl Ester Resin containing styrene and glycidyl methacrylate (GMA), as diluents, in the weight ratios 40:0, 30:10, 20:20, 10:30 and 0:40 were prepared at room temperature. Sharp exotherms were observed in DSC scans in the temperature range of 60–170 °C. The onset temperature ( T onset ), peak exothermic temperature ( T p ) and completion temperature ( T stop ) decreased with increase in GMA content in the ternary blend systems of CVER/styrene/GMA. A broad exotherm was observed after the initial sharp exotherm that was attributed to the etherification reaction. Cured samples were found to be stable up to 205–235 °C and started loosing weight above this temperature. Rapid decomposition was observed in the temperature range of 400–550 °C as evidenced by TGA analysis. Increase of GMA content in ternary blend systems of CVER/styrene/GMA lowered the tensile strength progressively and enhanced the impact strength and elongation-at-break. The cured films of VER containing mixture of styrene and GMA exhibited good gloss and impact resistance. The chemical resistance of cured films of VER containing mixture of styrene and GMA showed good resistance to acids, deionized water, synthetic sea water and mineral turpentine oil.
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modeling and simulation of curing kinetics for the cardanol based Vinyl Ester Resin by means of non isothermal dsc measurements
Materials Chemistry and Physics, 2012Co-Authors: Minakshi Sultania, Deepak SrivastavaAbstract:Abstract The cure kinetics of Vinyl Ester–styrene system was studied by non-isothermal differential scanning calorimetric (DSC) technique at four different heating rates. The kinetic parameters of the curing process were determined by isoconversional method for the kinetic analysis of the data obtained by the thermal treatment. Activation energy (Ea = 56.63 kJ mol−1) was evaluated for the cure process and a two-parameter (m, n) autocatalytic model was found to be the most adequate to describe the cure kinetics of the studied cardanol-based Vinyl Ester Resin. Non-isothermal DSC curves, as obtained by using the experimental data, show good agreement with the DSC curves obtained by theoretically calculated data.
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studies on the synthesis and curing of epoxidized novolac Vinyl Ester Resin from renewable resource material
European Polymer Journal, 2010Co-Authors: Minakshi Sultania, Deepak SrivastavaAbstract:Abstract Cardanol-based epoxidized novolac Vinyl Ester Resin (CNEVER) was synthesized by reacting cardanol-based epoxidized novolac (CNE) Resin and methacrylic acid (MA) (CNE:MA molar ratio 1:0.9) in presence of triphenylphosphine as catalyst at 90 °C. The CNE Resin was prepared by the reaction of cardanol-based novolac-type phenolic (CFN) Resin and epichlorohydrin, in basic medium, at 120 °C. The CFN Resin was synthesized by reacting cardanol (C) and formaldehyde (F) (C/F ratio = 1:0.7) with p -toluene sulphonic acid (PTSA) as catalyst (0.5 wt.%) at 120 °C for 7 h. The Resin products were analyzed by Fourier-transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analysis. The number-average molecular weight of the prepared CNEVER was found to be 859 gmol −1 as determined by gel permeation chromatographic (GPC) analysis. The Resin was cured by using the mixture of Resin, benzoyl peroxide, and styrene at 120 °C. The CNEVER Resin was found to be cured in 60 min at 120 °C. Differential scanning calorimetric (DSC) technique was used to investigate the curing behaviour. Single step mass loss in dynamic thermogravimetric (TG) trace of CNEVER was observed. Thermal stability of the Vinyl Ester sample containing 40 wt.% styrene was the highest amongst all other prepared systems.
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laminates based on Vinyl Ester Resin and glass fabric a study on the thermal mechanical and morphological characteristics
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Minakshi Sultania, S B Yadaw, Deepak SrivastavaAbstract:Abstract The effects of variation of styrene content on the thermal, mechanical and morphological behaviours of epoxy novolac Vinyl Ester Resin (EVER)/glass fabric laminate have been investigated. The Vinyl Ester Resin matrix was synthesized indigenously using epoxy novolac Resin and methacrylic acid catalyzed by triphenylphosphine at a temperature of 85 °C in nitrogen atmosphere. Fourier-transform infra-red spectroscopic (FT-IR) analysis was used to see the structural changes during the synthesis of the EVER. Differential scanning calorimetric (DSC) technique was used to investigate the curing behaviour of the EVER matrix. Exothermic peaks (Tp) appeared in the range of 117–127 °C for all the samples of epoxy Resin and EVERs. Thermal stability of the prepared samples was analyzed by dynamic thermogravimetric runs. The TG/DTG trace of epoxy showed two-step mass loss decomposition behaviour whereas that of Vinyl Ester Resin exhibited a single step mass loss. Mechanical properties such as tensile, flexural and impact strengths of the prepared laminates were determined and it was found cured Resin containing 40% styrene showed the best balance of properties and EVER/glass fabric laminates exhibited better properties as compared to the epoxy/glass fabric laminates Dynamic mechanical analyses of the samples were done to determine the viscoelastic properties. Tg decreased significantly with increased styrene concentration due to increase in cross-linking density. Cross-sections of the cured samples, which failed during impact testing, have been critically studied through scanning electron microscopic (SEM) analysis to gain insight into the phase morphology.
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Studies on the synthesis and curing of epoxidized novolac Vinyl Ester Resin from renewable resource material
European Polymer Journal, 2010Co-Authors: Minakshi Sultania, J. S.p. Rai, Deepak SrivastavaAbstract:Cardanol-based epoxidized novolac Vinyl Ester Resin (CNEVER) was synthesized by reacting cardanol-based epoxidized novolac (CNE) Resin and methacrylic acid (MA) (CNE:MA molar ratio 1:0.9) in presence of triphenylphosphine as catalyst at 90 °C. The CNE Resin was prepared by the reaction of cardanol-based novolac-type phenolic (CFN) Resin and epichlorohydrin, in basic medium, at 120 °C. The CFN Resin was synthesized by reacting cardanol (C) and formaldehyde (F) (C/F ratio = 1:0.7) with p-toluene sulphonic acid (PTSA) as catalyst (0.5 wt.%) at 120 °C for 7 h. The Resin products were analyzed by Fourier-transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analysis. The number-average molecular weight of the prepared CNEVER was found to be 859 gmol-1 as determined by gel permeation chromatographic (GPC) analysis. The Resin was cured by using the mixture of Resin, benzoyl peroxide, and styrene at 120 °C. The CNEVER Resin was found to be cured in 60 min at 120 °C. Differential scanning calorimetric (DSC) technique was used to investigate the curing behaviour. Single step mass loss in dynamic thermogravimetric (TG) trace of CNEVER was observed. Thermal stability of the Vinyl Ester sample containing 40 wt.% styrene was the highest amongst all other prepared systems. © 2010 Elsevier Ltd. All rights reserved.
Thomas H Hahn - One of the best experts on this subject based on the ideXlab platform.
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facile monomer stabilization approach to fabricate iron Vinyl Ester Resin nanocomposites
Composites Science and Technology, 2008Co-Authors: Amar B Karki, David P Young, Sung Park, John Willis, Thomas H HahnAbstract:Fe/Vinyl Ester Resin nanocomposites were fabricated by the monomer particle stabilization without any additional surfactant or coupling agent. Vinyl Ester monomer serves as a coupling agent with one side covalently bound onto the nanoparticle surface by a displacement reaction and the other end copolymerized with extra Vinyl Ester Resin to form a robust unity. The addition of iron nanoparticles favors the nanocomposite fabrication with a lower initial curing temperature. Vinyl Ester Resin in the nanocomposites becomes thermally stable as compared to the pure Vinyl Ester Resin. An enhanced mechanical property is observed due to the uniform particle dispersion and the introduced interfacial covalent bondage. The iron nanoparticles become magnetically harder (with a larger coercivity) after dispersion in the Vinyl Ester Resin matrix.
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Facile monomer stabilization approach to fabricate iron/Vinyl Ester Resin nanocomposites
Composites Science and Technology, 2008Co-Authors: Amar B Karki, David P Young, Sung Park, John Willis, Thomas H HahnAbstract:Fe/Vinyl Ester Resin nanocomposites were fabricated by the monomer particle stabilization without any additional surfactant or coupling agent. Vinyl Ester monomer serves as a coupling agent with one side covalently bound onto the nanoparticle surface by a displacement reaction and the other end copolymerized with extra Vinyl Ester Resin to form a robust unity. The addition of iron nanoparticles favors the nanocomposite fabrication with a lower initial curing temperature. Vinyl Ester Resin in the nanocomposites becomes thermally stable as compared to the pure Vinyl Ester Resin. An enhanced mechanical property is observed due to the uniform particle dispersion and the introduced interfacial covalent bondage. The iron nanoparticles become magnetically harder (with a larger coercivity) after dispersion in the Vinyl Ester Resin matrix.
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magnetic and magnetoresistance behaviors of particulate iron Vinyl Ester Resin nanocomposites
Journal of Applied Physics, 2008Co-Authors: Thomas H Hahn, Amar B Karki, David P YoungAbstract:Magnetoresistance (MR) behavior of Vinyl Ester monomer stabilized iron nanoparticles and heat-treated Vinyl Ester Resin nanocomposites reinforced with iron nanoparticles were investigated. Vinyl Ester monomer serves as a coupling agent with one side covalently bound onto the nanoparticle surface by a displacement reaction and the other end copolymerized with extra Vinyl Ester Resin to form a robust entity. The particle loading and type of material (polymer or carbonized polymer) have a significant effect on the magnetic and MR properties. The heat-treated nanocomposites follow a tunneling conduction. After reduction annealing, the obtained nanocomposites possess a room temperature MR of 8.3 % at a field of 90 kOe.
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fabrication and characterization of iron oxide nanoparticles reinforced Vinyl Ester Resin nanocomposites
Composites Science and Technology, 2008Co-Authors: Yutong Li, Ho Wai Ng, Sergy Prikhodko, Thomas H HahnAbstract:Abstract Robust magnetic Vinyl Ester Resin nanocomposites reinforced with iron oxide (Fe2O3) nanoparticles were fabricated. The particle functionalization with a bi-functional coupling agent methacryloxypropyl-trimethoxysilane (MPS) was observed to have a significant effect on the curing process and subsequent physical properties of the nanocomposites. Particle functionalization favors the composite fabrication with a lower curing temperature as compared to the as-received nanoparticles filled Vinyl Ester Resin nanocomposites. Thermo-gravimetric analysis showed an increased thermo-stability in the functionalized nanoparticles filled Vinyl Ester Resin nanocomposites as compared to the unmodified nanoparticle filled counterparts. The more uniform particle dispersion and the chemical bonding between nanoparticle and Vinyl Ester Resin matrix were found to contribute to the increased thermal stability and enhanced tensile strength. The nanoparticles become magnetically harder after incorporation into the Vinyl Ester Resin matrix.
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cuo nanoparticle filled Vinyl Ester Resin nanocomposites fabrication characterization and property analysis
Composites Science and Technology, 2007Co-Authors: Zhanhu Guo, Tony Pereira, Roberto Scaffaro, Xiaofeng Liang, Thomas H HahnAbstract:Abstract Both unmodified cupric oxide (CuO) nanoparticles and those functionalized with a bi-functional coupling agent methacryloxypropyl-trimethoxysilane (MPS) were used to fabricate Vinyl-Ester Resin polymeric nanocomposites. The nanoparticle functionalization was observed to have a significant effect on the physical properties of the cupric oxide filled Vinyl-Ester Resin nanocomposite. Thermal degradation study by thermo-gravimetric analysis (TGA) showed the increased thermo-stability in the functionalized-nanoparticle-filled Vinyl-Ester Resin nanocomposites as compared with the unmodified-nanoparticle-filled counterparts. The more uniform particle dispersion and the chemical bond between nanoparticle and Vinyl-Ester Resin were found to contribute to the increased thermal stability and enhanced tensile strength.
Minakshi Sultania - One of the best experts on this subject based on the ideXlab platform.
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modeling and simulation of curing kinetics for the cardanol based Vinyl Ester Resin by means of non isothermal dsc measurements
Materials Chemistry and Physics, 2012Co-Authors: Minakshi Sultania, Deepak SrivastavaAbstract:Abstract The cure kinetics of Vinyl Ester–styrene system was studied by non-isothermal differential scanning calorimetric (DSC) technique at four different heating rates. The kinetic parameters of the curing process were determined by isoconversional method for the kinetic analysis of the data obtained by the thermal treatment. Activation energy (Ea = 56.63 kJ mol−1) was evaluated for the cure process and a two-parameter (m, n) autocatalytic model was found to be the most adequate to describe the cure kinetics of the studied cardanol-based Vinyl Ester Resin. Non-isothermal DSC curves, as obtained by using the experimental data, show good agreement with the DSC curves obtained by theoretically calculated data.
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studies on the synthesis and curing of epoxidized novolac Vinyl Ester Resin from renewable resource material
European Polymer Journal, 2010Co-Authors: Minakshi Sultania, Deepak SrivastavaAbstract:Abstract Cardanol-based epoxidized novolac Vinyl Ester Resin (CNEVER) was synthesized by reacting cardanol-based epoxidized novolac (CNE) Resin and methacrylic acid (MA) (CNE:MA molar ratio 1:0.9) in presence of triphenylphosphine as catalyst at 90 °C. The CNE Resin was prepared by the reaction of cardanol-based novolac-type phenolic (CFN) Resin and epichlorohydrin, in basic medium, at 120 °C. The CFN Resin was synthesized by reacting cardanol (C) and formaldehyde (F) (C/F ratio = 1:0.7) with p -toluene sulphonic acid (PTSA) as catalyst (0.5 wt.%) at 120 °C for 7 h. The Resin products were analyzed by Fourier-transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analysis. The number-average molecular weight of the prepared CNEVER was found to be 859 gmol −1 as determined by gel permeation chromatographic (GPC) analysis. The Resin was cured by using the mixture of Resin, benzoyl peroxide, and styrene at 120 °C. The CNEVER Resin was found to be cured in 60 min at 120 °C. Differential scanning calorimetric (DSC) technique was used to investigate the curing behaviour. Single step mass loss in dynamic thermogravimetric (TG) trace of CNEVER was observed. Thermal stability of the Vinyl Ester sample containing 40 wt.% styrene was the highest amongst all other prepared systems.
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laminates based on Vinyl Ester Resin and glass fabric a study on the thermal mechanical and morphological characteristics
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Minakshi Sultania, S B Yadaw, Deepak SrivastavaAbstract:Abstract The effects of variation of styrene content on the thermal, mechanical and morphological behaviours of epoxy novolac Vinyl Ester Resin (EVER)/glass fabric laminate have been investigated. The Vinyl Ester Resin matrix was synthesized indigenously using epoxy novolac Resin and methacrylic acid catalyzed by triphenylphosphine at a temperature of 85 °C in nitrogen atmosphere. Fourier-transform infra-red spectroscopic (FT-IR) analysis was used to see the structural changes during the synthesis of the EVER. Differential scanning calorimetric (DSC) technique was used to investigate the curing behaviour of the EVER matrix. Exothermic peaks (Tp) appeared in the range of 117–127 °C for all the samples of epoxy Resin and EVERs. Thermal stability of the prepared samples was analyzed by dynamic thermogravimetric runs. The TG/DTG trace of epoxy showed two-step mass loss decomposition behaviour whereas that of Vinyl Ester Resin exhibited a single step mass loss. Mechanical properties such as tensile, flexural and impact strengths of the prepared laminates were determined and it was found cured Resin containing 40% styrene showed the best balance of properties and EVER/glass fabric laminates exhibited better properties as compared to the epoxy/glass fabric laminates Dynamic mechanical analyses of the samples were done to determine the viscoelastic properties. Tg decreased significantly with increased styrene concentration due to increase in cross-linking density. Cross-sections of the cured samples, which failed during impact testing, have been critically studied through scanning electron microscopic (SEM) analysis to gain insight into the phase morphology.
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Studies on the synthesis and curing of epoxidized novolac Vinyl Ester Resin from renewable resource material
European Polymer Journal, 2010Co-Authors: Minakshi Sultania, J. S.p. Rai, Deepak SrivastavaAbstract:Cardanol-based epoxidized novolac Vinyl Ester Resin (CNEVER) was synthesized by reacting cardanol-based epoxidized novolac (CNE) Resin and methacrylic acid (MA) (CNE:MA molar ratio 1:0.9) in presence of triphenylphosphine as catalyst at 90 °C. The CNE Resin was prepared by the reaction of cardanol-based novolac-type phenolic (CFN) Resin and epichlorohydrin, in basic medium, at 120 °C. The CFN Resin was synthesized by reacting cardanol (C) and formaldehyde (F) (C/F ratio = 1:0.7) with p-toluene sulphonic acid (PTSA) as catalyst (0.5 wt.%) at 120 °C for 7 h. The Resin products were analyzed by Fourier-transform infra-red (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analysis. The number-average molecular weight of the prepared CNEVER was found to be 859 gmol-1 as determined by gel permeation chromatographic (GPC) analysis. The Resin was cured by using the mixture of Resin, benzoyl peroxide, and styrene at 120 °C. The CNEVER Resin was found to be cured in 60 min at 120 °C. Differential scanning calorimetric (DSC) technique was used to investigate the curing behaviour. Single step mass loss in dynamic thermogravimetric (TG) trace of CNEVER was observed. Thermal stability of the Vinyl Ester sample containing 40 wt.% styrene was the highest amongst all other prepared systems. © 2010 Elsevier Ltd. All rights reserved.
Gengliang Yang - One of the best experts on this subject based on the ideXlab platform.
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the fabrication of monolithic capillary column based on poly bisphenol a epoxy Vinyl Ester Resin co ethylene glycol dimethacrylate and its applications for the separation of small molecules in high performance liquid chromatography
Journal of Chromatography A, 2013Co-Authors: Lijuan Wang, Gengliang YangAbstract:Abstract A new polymeric monolith was synthesized in fused-silica capillary by in situ polymerization technique. In the polymerization, bisphenol A epoxy Vinyl Ester Resin (VER) was used as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the crosslinking monomer, 1,4-butanediol, 1-propanol and water as the co-porogens, and azobisisobutyronitrile (AIBN) as the initiator. The conditions of polymerization have been optimized. Morphology of the prepared poly (VER-co-EDMA) monolith was investigated by the scanning electron microscopy (SEM); pore properties were assayed by mercury porosimetry and nitrogen adsorption. The optimized poly (VER-co-EDMA) monolith showed a uniform structure, good permeability and mechanical stability. Then, the column was used as the stationary phase of high performance liquid chromatography (HPLC) to separate the mixture of benzene derivatives. The best column efficiency achieved for phenol was 235 790 theoretical plates per meter. Baseline separations of benzene derivatives and halogenated benzene compounds under optimized isocratic mode conditions were achieved with high column efficiency. The column showed good reproducibility: the relative standard deviation (RSD) values based on the retention times (n = 3) for run-to-run, column-to-column and batch-to-batch were less than 0.98, 1.68, 5.48%, respectively. Compared with poly (BMA-co-EDMA) monolithic column, the proposed monolith exhibited more efficiency in the separation of small molecules.
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Synthesis and Characterization of Novel Poly(Vinyl Ester Resin-co-Ethylene Dimethacrylate) Monolithic Network Columns
Designed Monomers and Polymers, 2012Co-Authors: Shenghui Li, Gengliang YangAbstract:In this report we introduce a new monolithic column for HPLC. The monolithic column was prepared using Vinyl Ester Resin-co-ethylene dimethacrylate as the monomer. Using the free radical polymerization method a polymer network was formed, which was different from the traditional globular particles. The main factors affecting the porous structure of Vinyl Ester (VE) Resin-based monolithic columns were investigated. By varying the porogen solvent, its content and the amount of initiator, different porous structures could be obtained. In order to evaluate the mechanical stability of the column material, the pressure drop across the column was measured at different flow-rates. Finally, using phenol, resorcinol and catechol as the test compounds, the normal-phase character of the poly(Vinyl Ester Resin-co-ethylene dimethacrylate) monolith was evident.
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preparation and characterization of porous poly Vinyl Ester Resin monoliths as separation media
Journal of Applied Polymer Science, 2011Co-Authors: Jing Yang, Gengliang Yang, Qiaoxia ZhangAbstract:Porous poly(Vinyl Ester) Resin monolithic supports were first prepared by radical polymerization of the continuous phase of oil in water high-internal-phase emulsions. Vinyl Ester (VE) Resin was used as the monomer, ethylene glycol dimethacrylate was used as a crosslinker, and poloxamer 127 was used as the emulsifier in the emulsion polymerization. The prepared columns were evaluated by scanning electron microscopy, mercury intrusion porosimetry, and Fourier transform infrared spectroscopy to observe the morphological characteristics and confirm the absorbance based on the VE Resin polymer. The obtained monolith showed not only higher column permeability but also lower back pressure and higher column efficiency. To investigate the absorption performance of the monolithic column, a maximum loading capacity experiment was also applied with lysozyme (Lys), and the results show that the maximum adsorption of the poly(Vinyl Ester) Resin monolith was 1.579 mg/g. Moreover, the capabilities of separation on this column in conjunction with high-performance liquid chromatography were investigated. Immunoglobulin could be separated from human plasma and chicken egg yolk with high resolution within 4 min. Additionally, fast separation of two mode proteins (interleukin-18 and Lys) was achieved on the monolith within 2 min at the rate of 1445 cm/h, which demonstrated the potential of the poly(Vinyl Ester) Resin monolith for the fast separation of proteins. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
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separation of immunoglobulin in conjunction with high performance liquid chromatography using poly Vinyl Ester Resin monolith
Chinese Journal of Chemistry, 2009Co-Authors: Guanqun Yang, Gengliang Yang, Xiaojuan Feng, Xinru YangAbstract:Using Vinyl Ester Resin both as the monomer and the crosslinker, 2,2-azobis(2-methylpropionitrile) (AIBN) as initiator, poly(Vinyl Ester Resin) monolithic column was prepared to separate the immunoglobulin G (IgG) and yolk of eggs (IgY) from human plasma and egg yolk by HPLC respectively. The influence of concentration and pH of mobile phase on the chromatographic performance was investigated. Scanning electron microcopy showed that the poly(Vinyl Ester Resin) monolithic stationary phase had a through-pore structure. Dynamic capacity of IgG on the polymeric monolithic column was investigated. The monolithic column had good flow-through properties and high resolution. The maximum adsorptive amount of IgG was 144 µg·g−1.
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separation of immunoglobulin g and immunoglobulin y on poly Vinyl Ester Resin co ethylene dimethacrylate monolith
Chinese Journal of Analytical Chemistry, 2009Co-Authors: Xiaojuan Feng, Gengliang Yang, Guanqun YangAbstract:Abstract With Vinyl Ester Resin as monomer, ethylene glycol dimethacrylate (EDMA) as the crosslinker, dodecanol as porogenic solvents, and 2,2'-azobisisobutyronitrile (AIBN) as initiators, a poly(Vinyl Ester Resin-co-ethylene dimethacrylate) monolithic column was prepared by “in-situ” process. The monolith was further derivative by 3-glycidoxypropyltrimethoxysilane and then hydrolyzed in 0.25 M sulfuric acid to prepare a diol column. The effects of pH value and buffer concentration on the retention of IgG were investigated and the separation of IgG from human plasma was operated. The separation of IgY from chicken egg yolk at different buffer concentration and the effect of spacer arm on the separation were also investigated. The results show that the monolith with spacer arm had a higher separation capacity. Moreover, the adsorption capacity of the column was investigated and the maximum adsorption amount was 35 μg −1 .
Chun Pu Hu - One of the best experts on this subject based on the ideXlab platform.
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interpenetrating polymer networks of polyurethane and graft Vinyl Ester Resin polyurethane formed with toluene diisocyanate
European Polymer Journal, 2000Co-Authors: Gui You Wang, Yu Ling Wang, Chun Pu HuAbstract:Abstract For enhancing the compatibility and/or the interpenetration of the simultaneous interpenetrating networks (SINs) composed of polyurethane (PU) formed with toluene diisocyanates (TDI) and Vinyl Ester Resin (VER) in which there were no chemical bonds between the two networks, a series of well-defined graft VERs consisting of different side chains were synthesized and characterized. The side chains existing in such graft VERs were formed from TDI and butanol (called BO-g-VER) or poly(oxypropylene) with different molecular weights (Mw: 200 and 390, called 200-g-VER and 390-g-VER, respectively). Differential scanning calorimetry measurements and the scanning electron microscopy observation indicated that the morphology of graft VERs had a great effect on the interpenetration and/or the compatibility between the two networks for PU/graft VER SIN systems. The SIN consisting of 200-g-VER exhibits excellent interpenetration between the two networks, as 200-g-VER network is a compatible system. For SIN composed of BO-g-VER, the compatibility between the two phases is greatly improved, since there are more content of urethane groups existing in grafts which should mix well with those in the PU network. Thus, the mechanical properties increase appreciably with the increase of graft VER content for these two SIN specimens. However, the reinforcement effect of 390-g-VER network on PU network is poor, as such a SIN shows a serious phase separation due to the micro-phase separated morphology of 390-g-VER network’s own self.
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interpenetrating polymer networks of polyurethane and graft Vinyl Ester Resin polyurethane formed with diphenylmethane diisocyanate
Journal of Polymer Science Part A, 2000Co-Authors: Gui You Wang, Chun Pu HuAbstract:For enhancing the compatibility and/or the interpenetration of the simultaneous interpenetrating networks (SINs) composed of polyurethane (PU) formed with uretonimine modified 4,4′-diphenylmethane diisocyanate and Vinyl Ester Resin (VER), a series of graft VERs consisting of different lengths of side chains were synthesized and characterized. It was found that there exists some limited short-range order due to the strong hydrogen bonding in the graft VER network composed of butanol side chains (BO-g-VER). The graft VER network composed of poly(oxypropylene) (PPO) side chains (Mn: 200, 200-g-VER) showed compatible system, while the VER network consisting of longer PPO grafts (Mn: 390, 390-g-VER) exhibited microphase separated morphology. Based upon the DSC and FTIR measurements as well as the SEM and TEM observation, the lengths of side chains existing in graft VER network have great effect on the morphologies of PU/graft VER SINs. For PU/BO-g-VER SINs, there has been some interpenetration between the two networks because of the miscibility between the BO-g-VER network and the hard segments existing in the PU network. For PU/200-g-VER SINs, the good compatibility and/or the interpenetration between the two phases was observed, since the long-range ordered structure of hard segments in PU phase was greatly suppressed, resulting from the excellent miscibility between the urethane groups as well as the PPO side chains existing in the 200-g-VER network and those in the PU network, respectively. Thus, the strong reinforcement effect of these two graft networks on the PU network and the excellent mechanical properties of the SIN systems were observed. However, the PU/390-g-VER SINs showed the complicated morphologies because of existing microphase- separated morphology of 390-g-VER network in itself. In this case, the enhancement effect of such a graft VER network on the PU network is limited. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 136–144, 2000
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polymerization of polyurethane and Vinyl Ester Resin interpenetrating polymer networks during reaction injection moulding process
Polymer, 1997Co-Authors: Chun Pu Hu, Zhiping Zhang, Sheng Kang YingAbstract:Abstract The reaction kinetics of polyurethane and Vinyl Ester Resin interpenetrating polymer network (PU/VER SIN) during reaction injection moulding (RIM) polymerization has been on-line monitored by using a Fourier transform infrared (FTi.r.) spectrometer linked up with a portable mini-RIM machine. For using VER, in which the pendent hydroxyl groups were capped with acetyl groups to minimize the possibility of chemical binding between the two networks, the two pairs of reactants interfere with each other during the course of synthesis. The unusual polymerization kinetics behaviour observed could be correlated well with the change of morphology of the system. For using VER containing pendent hydroxyl groups, the occurrence of chemical binding between the two networks could greatly affect the reaction kinetics and morphology of the system. © 1997 Elsevier Science Ltd.
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polymerization kinetics of polyurethane and Vinyl Ester Resin interpenetrating polymer networks by using fourier transform infrared spectroscopy
Journal of Applied Polymer Science, 1996Co-Authors: Chun Pu Hu, Zhiping Zhang, Sheng Kang YingAbstract:Fourier transform infrared spectroscopy (FTIR) was applied to the study of polymerization kinetics of simultaneous interpenetrating polymer networks (SINs) composed of polyurethane (PU) and Vinyl Ester Resin (VER), in which the pendent hydroxyl groups were capped with acetyl groups to minimize the possibility of chemical binding between the two networks. It was found that during the course of synthesis the two pairs of reactants interfere with each other in the SIN systems, giving rise to depressed reaction rates, although they follow different polymerization mechanisms. Increasing the reaction temperature could be more effective than increasing the free-radical initiator level with regard to the final conversions of both components. The reaction sequence could be varied through the amount of the step-growth polymerization catalyst and free-radical initiator as well as the reaction temperature adjustment. Using VER containing pendent hydroxyl groups could strongly affect the reaction kinetics of such SINs and lead to hybrid structures. The quick formation of one network would always depress the conversion of the other network in all SINs studied. © 1996 John Wiley & Sons, Inc.
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thermal analysis during the formation of polyurethane and Vinyl Ester Resin interpenetrating polymer networks
Polymer, 1996Co-Authors: Chun Pu Hu, Sheng Kang YingAbstract:Abstract A Vinyl Ester Resin (VER) with negligible carboxyl and hydroxyl groups was prepared from bisphenol A epoxy Resin and α-methacrylic acid in combination with styrene. Simultaneous interpenetrating polymer networks (SINs) consisting of this VER and polyurethane (PU) could be obtained with negligible intercomponent chemical binding between the two networks. The synthetic courses of these SINs were monitored with differential scanning calorimetry. While the amount of PU formation remained almost the same, the copolymerization of VER was greatly affected by temperature, by the composition of SINs and by the molecular crosslinking nature of both components. Furthermore, the thermal behaviour during the synthesis of SINs from VER containing hydroxyl groups was examined and showed that, when the secondary hydroxyl groups in VER were included for the metering of isocyanate in the feed for PU formation, inter-component chemical binding between the two networks should occur, resulting in a completely different molecular architecture of SINs.
