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A new investigation of polymaleamides as kinetic hydrate inhibitors – Improved performance and compatibility with high salinity brines. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116719] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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2
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Facile pore structure control of poly(vinylidene fluoride) membrane for oil/water separation. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.117305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Kadota K, Nogami S, Uchiyama H, Tozuka Y. Controlled release behavior of curcumin from kappa-carrageenan gels with flexible texture by the addition of metal chlorides. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2019.105564] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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The Hofmeister series: Specific ion effects in aqueous polymer solutions. J Colloid Interface Sci 2019; 555:615-635. [PMID: 31408761 DOI: 10.1016/j.jcis.2019.07.067] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/21/2022]
Abstract
Specific ion effects in aqueous polymer solutions have been under active investigation over the past few decades. The current state-of-the-art research is primarily focused on the understanding of the mechanisms through which ions interact with macromolecules and affect their solution stability. Hence, we herein first present the current opinion on the sources of ion-specific effects and review the relevant studies. This includes a summary of the molecular mechanisms through which ions can interact with polymers, quantification of the affinity of ions for the polymer surface, a thermodynamic description of the effects of salts on polymer stability, as well as a discussion on the different forces that contribute to ion-polymer interplay. Finally, we also highlight future research issues that call for further scrutiny. These include fundamental questions on the mechanisms of ion-specific effects and their correlation with polymer properties as well as a discussion on the specific ion effects in more complex systems such as mixed electrolyte solutions.
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Uchiyama H, Nogami S, Katayama K, Hayashi K, Kadota K, Tozuka Y. Jelly containing composite based on α-glucosyl stevia and polyvinylpyrrolidone: Improved dissolution property of curcumin. Eur J Pharm Sci 2018; 117:48-54. [PMID: 29428541 DOI: 10.1016/j.ejps.2018.02.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/23/2018] [Accepted: 02/07/2018] [Indexed: 11/25/2022]
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Baumann J, Köser J, Arndt D, Filser J. The coating makes the difference: acute effects of iron oxide nanoparticles on Daphnia magna. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 484:176-184. [PMID: 24705300 DOI: 10.1016/j.scitotenv.2014.03.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 03/03/2014] [Accepted: 03/03/2014] [Indexed: 05/29/2023]
Abstract
The surface of nanoparticles (NP) is often functionalized with a capping agent to increase their colloidal stability. Having a strong effect on the characteristics of NP, the coating might already determine the risk from NP to organisms and the environment. In this study identical iron oxide nanoparticles (IONP; Ø 5-6nm) were functionalized with four different coatings: ascorbate (ASC-IONP), citrate (CIT-IONP), dextran (DEX-IONP), and polyvinylpyrrolidone (PVP-IONP). Ascorbate and citrate stabilize NP via electrostatic repulsion whereas dextran and polyvinylpyrrolidone are steric stabilizers. All IONP were colloidally stable over several weeks. Their acute effects on neonates of the waterflea Daphnia magna were investigated over 96h. The highest immobilizing effect was found for ASC- and DEX-IONP. In the presence of neonates, both agglomerated or flocculated and adsorbed to the carapace and filtering apparatuses, inducing high immobilization. Lower immobilization was found for CIT-IONP. Their effect was hypothesized to partly originate from an increased release of dissolved iron and the ability to form reactive oxygen species (ROS). Furthermore, incomplete ecdysis occurred at high concentrations of ASC-, DEX-, and CIT-IONP. PVP-IONP did not induce any negative effect, although high quantities were visibly ingested by the daphnids. PVP-IONP had the highest colloidal stability without any occurring agglomeration, adsorption, or dissolution. Only strong swelling of the PVP coating was observed in medium, highly increasing the hydrodynamic diameter. Each coating caused individual effects. Toxicity cannot be correlated to hydrodynamic diameter or the kind of stabilizing forces. Effects are rather linked to decreasing colloidal stability, the release of ions from the core material or the ability to form ROS, respectively.
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Affiliation(s)
- Jonas Baumann
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen, Leobener Strasse UFT, D-28359 Bremen, Germany.
| | - Jan Köser
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen, Leobener Strasse UFT, D-28359 Bremen, Germany.
| | - Darius Arndt
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen, Leobener Strasse UFT, D-28359 Bremen, Germany.
| | - Juliane Filser
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen, Leobener Strasse UFT, D-28359 Bremen, Germany.
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Zhang AQ, Li HJ, Qian DJ, Chen M. Kinetically-controlled template-free synthesis of hollow silica micro-/nanostructures with unusual morphologies. NANOTECHNOLOGY 2014; 25:135608. [PMID: 24598146 DOI: 10.1088/0957-4484/25/13/135608] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report a kinetically-controlled template-free room-temperature production of hollow silica materials with various novel morphologies, including tubes, crutches, ribbons, bundles and bells. The obtained products, which grew in a well-controlled manner, were monodispersed in shape and size. The role of ammonia, sodium citrate, polyvinylpyrrolidone, chloroauric acid and NaCl in shape control is discussed in detail. The oriented growth of these micro-/nanostructures directed by reverse micelles followed a solution-solution-solid (SSS) mechanism, similar to the classic vapor-liquid-solid mechanism. The evolution processes of silica rods, tubes, crutches, bundles and bells were recorded using transmission electron microscopy to prove the SSS mechanism.
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Affiliation(s)
- An-Qi Zhang
- Department of Materials Science, Fudan University, Shanghai 200433, People's Republic of China
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Renamayor CS, Pastoriza A, Usma CL, Pierola IF. Ionic liquid–water mixtures as solvents for poly(N-vinylimidazole). Colloid Polym Sci 2013. [DOI: 10.1007/s00396-013-2963-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Arndt D, Gesing TM, Bäumer M. Surface Functionalization of Iron Oxide Nanoparticles and their Stability in Different Media. Chempluschem 2012. [DOI: 10.1002/cplu.201200065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Alsarra IA, Hamed AY, Alanazi FK, Neau SH. Rheological and mucoadhesive characterization of poly(vinylpyrrolidone) hydrogels designed for nasal mucosal drug delivery. Arch Pharm Res 2011; 34:573-82. [PMID: 21544722 DOI: 10.1007/s12272-011-0407-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 07/23/2010] [Accepted: 09/11/2010] [Indexed: 11/30/2022]
Abstract
Poly(vinylpyrrolidone) (PVP) hydrogels were crosslinked by gamma irradiation to add structure and rigidity, and then rheological and mucoadhesive properties were evaluated. The effects of PVP concentration, radiation dose, and additives, such as poly(ethylene glycol) (PEG) and glycerol, on rheological properties were investigated. In an oscillatory analysis, an increase in polymer concentrations increased the storage modulus (G') and the loss modulus (G″) but decreased the loss tangent (tan δ < 1). The relationships between G'or G″ and the frequency levelled off at higher frequencies, which is indicative of polymer chain entanglement and network formation. Each of the 6% PVP hydrogels exhibited plastic flow with rheopectic behavior. PVP concentration, radiation dose, and the presence of PEG or glycerol influenced the rheological and mucoadhesive properties of the hydrogels. However, adding acyclovir to the formulation did not have a profound effect on the rheological behavior of the hydrogels. The results suggest that a 3% PVP hydrogel with 1% PEG crosslinked with 20 kGy is the most appropriate hydrogel. The results demonstrated the successful complementary application of oscillatory and flow rheometry to characterize and develop a hydrogel for mucosal drug administration.
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Affiliation(s)
- Ibrahim A Alsarra
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia.
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Ntim SA, Sae-Khow O, Witzmann FA, Mitra S. Effects of polymer wrapping and covalent functionalization on the stability of MWCNT in aqueous dispersions. J Colloid Interface Sci 2010; 355:383-8. [PMID: 21236442 DOI: 10.1016/j.jcis.2010.12.052] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/15/2010] [Accepted: 12/16/2010] [Indexed: 10/18/2022]
Abstract
The colloidal behavior of aqueous dispersions of functionalized multiwall carbon nanotubes (F-CNTS) formed via carboxylation and polymer wrapping with polyvinyl pyrrolidone (PVP) is presented. The presence of polymer on the nanotube surface provided steric stabilization, and the aggregation behavior of the colloidal system was quite different from its covalently functionalized analog. Based on hydrophobicity index, particle size distribution, zeta potential as well as the aggregation kinetics studied using time-resolved dynamic light scattering, the PVP wrapped CNT was somewhat less prone to agglomeration. However, its long-term stability was lower, and this was attributed to the partial unwrapping of the polyvinyl pyrrolidone layer on the CNT surface.
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Affiliation(s)
- Susana Addo Ntim
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
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López-Donaire ML, Parra-Cáceres J, Fernández-Gutiérrez M, Vázquez-Lasa B, Román JS. Polymeric drugs based on random copolymers with antimitotic activity. Biomacromolecules 2010; 11:2478-86. [PMID: 20695637 DOI: 10.1021/bm100672c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polymeric drugs based on random copolymers with antimitotic activity were obtained by free radical copolymerization of oleyl 2-acetamido-2-deoxy-α-d-glucopyranoside methacrylate (OAGMA) and 2-ethyl-(2-pyrrolidone) methacrylate (EPM) at low and high conversion and analyzed in terms of microstructure, physicochemical, and biological properties. Reactivity ratios of monomers were found to be r(OAGMA) = 1.34 and r(EPM) = 0.98, indicating the obtaining of statistical copolymers with random sequence distribution of the comonomeric units in the macromolecular chains. The glass transition temperature of the copolymers presents a negative deviation from the predicted values according to the Fox equation, suggesting a higher flexibility of the alternating diad. Copolymeric systems with OAGMA contents between 10-50 mol % presented thermosensitive behavior in a heating process showing cloud point temperatures (CPT) in the range 45-28 °C with increasing OAGMA content and hysteresis in one heating-and-cooling cycle. In vitro glycolipid release studies revealed the stability of the ester group in culture medium. The polymeric drugs with 30 and 50 mol % OAGMA presented antimitotic activity on a human glioblastoma line, but they were less toxic on normal human fibroblast cultures.
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Affiliation(s)
- M L López-Donaire
- Institute of Polymer Science and Technology, CSIC, Juan de la Cierva, 3, 28006 Madrid, Spain
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Lü S, Liu M, Ni B, Gao C. A novel pH- and thermo-sensitive PVP/CMC semi-IPN hydrogel: Swelling, phase behavior, and drug release study. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/polb.22040] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Hamcerencu M, Desbrieres J, Popa M, Riess G. Stimuli-Sensitive Xanthan Derivatives/N-Isopropylacrylamide Hydrogels: Influence of Cross-Linking Agent on Interpenetrating Polymer Network Properties. Biomacromolecules 2009; 10:1911-22. [DOI: 10.1021/bm900318g] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mihaela Hamcerencu
- Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environment Protection, “Gh. Asachi” Technical University, Bd. D. Mangeron, nr. 71 A, 700050 Iasi, Romania, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux (IPREM/EPCP), Université de Pau et des Pays de l’Adour, UMR CNRS 5254, Helioparc Pau Pyrénées, 2, av. President Angot, 64053 Pau Cedex 09, France, and Laboratoire de Chimie Organique, Bioorganique et Macromoléculaire, Université de Haute
| | - Jacques Desbrieres
- Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environment Protection, “Gh. Asachi” Technical University, Bd. D. Mangeron, nr. 71 A, 700050 Iasi, Romania, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux (IPREM/EPCP), Université de Pau et des Pays de l’Adour, UMR CNRS 5254, Helioparc Pau Pyrénées, 2, av. President Angot, 64053 Pau Cedex 09, France, and Laboratoire de Chimie Organique, Bioorganique et Macromoléculaire, Université de Haute
| | - Marcel Popa
- Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environment Protection, “Gh. Asachi” Technical University, Bd. D. Mangeron, nr. 71 A, 700050 Iasi, Romania, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux (IPREM/EPCP), Université de Pau et des Pays de l’Adour, UMR CNRS 5254, Helioparc Pau Pyrénées, 2, av. President Angot, 64053 Pau Cedex 09, France, and Laboratoire de Chimie Organique, Bioorganique et Macromoléculaire, Université de Haute
| | - Gérard Riess
- Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environment Protection, “Gh. Asachi” Technical University, Bd. D. Mangeron, nr. 71 A, 700050 Iasi, Romania, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux (IPREM/EPCP), Université de Pau et des Pays de l’Adour, UMR CNRS 5254, Helioparc Pau Pyrénées, 2, av. President Angot, 64053 Pau Cedex 09, France, and Laboratoire de Chimie Organique, Bioorganique et Macromoléculaire, Université de Haute
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Alsarra IA, Hamed AY, Mahrous GM, El Maghraby GM, Al-Robayan AA, Alanazi FK. Mucoadhesive polymeric hydrogels for nasal delivery of acyclovir. Drug Dev Ind Pharm 2009; 35:352-62. [PMID: 18770068 DOI: 10.1080/03639040802360510] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The study evaluated different mucoadhesive polymeric hydrogels for nasal delivery of acyclovir. Gels containing poly-N-vinyl-2-pyrrolidone (PVP) were prepared with crosslinking achieved by irradiation with a radiation dose of 15 kGy being as efficient as 20 kGy. Gels containing chitosan and carbopol were also evaluated. The mucoadhesive properties of gels were measured by a modification of a classical tensile experiment, employing a tensile tester and using freshly excised sheep nasal mucosa. Considering the mucoadhesive force, chitosan gel and gel prepared with 3% PVP in presence of polyethylene glycol (PEG) 600 were the most efficient. The in vitro drug release depended on the gel composition. Higher release rates were obtained from PVP gels compared to chitosan or carbopol gels. The release rate of drug from PVP gels was increased further in presence of PEG or glycerol. Histopathological investigations proved that the PVP was a safe hydrogel to be used for mucosal delivery. The PEG in gel formulations caused less damages to the nasal mucosal compared to formulation containing glycerol.
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Affiliation(s)
- Ibrahim A Alsarra
- Kayyali Chair for Pharmaceutical Industry, Pharmaceutical Technology Center, College of Pharmacy, King Saud University, Riyadh, Kingdom of Saudi Arabia.
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Chen X, Matteucci ME, Lo CY, Johnston KP, Williams RO. Flocculation of Polymer Stabilized Nanocrystal Suspensions to Produce Redispersible Powders. Drug Dev Ind Pharm 2009; 35:283-96. [DOI: 10.1080/03639040802282896] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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Özdemir C, Güner A. Solution thermodynamics of poly(ethylene glycol)/water systems. J Appl Polym Sci 2006. [DOI: 10.1002/app.23191] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Synthesis of persulfate containing poly (N-vinyl-2-pyrrolidone) (PVP) hydrogels in aqueous solutions by γ-induced radiation. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2004.04.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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Can HK, Denizli BK, Kavlak S, Guner A. Preparation and swelling studies of biocompatible hydrogel systems by using gamma radiation-induced polymerization. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2003.12.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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de Queiroz AAA, França ÉJ, Abraham GA, Roman JS. Drug complexation and physicochemical properties of vinylpyrrolidone-N,N′-dimethylacrylamide copolymers. J Appl Polym Sci 2004. [DOI: 10.1002/app.20552] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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22
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Can HK, Kirci B, Kavlak S, Güner A. Removal of some textile dyes from aqueous solutions by poly(N-vinyl-2-pyrrolidone) and poly(N-vinyl-2-pyrrolidone)/K2S2O8 hydrogels. Radiat Phys Chem Oxf Engl 1993 2003. [DOI: 10.1016/s0969-806x(03)00348-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Can HK, Kavlak S, Kırcı B, Güner A. Swelling behavior of poly(N-vinyl-2-pyrrolidone) and poly(N-vinyl-2-pyrrolidone)/K2S2O8hydrogels in α-lactose solutions. ADVANCES IN POLYMER TECHNOLOGY 2003. [DOI: 10.1002/adv.10054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kavuklu Ö, Güner A, Tunoğlu N. Polyester of dimethyl 7-(N-pyrrolidinyl)-2,7-cycloheptadiene-1,2-dicarboxylate and its lithium triflate complex. ADVANCES IN POLYMER TECHNOLOGY 2002. [DOI: 10.1002/adv.2001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kirci B, Güner A. Effect of phenol derivatives on molecular dimensions of poly(N-vinyl-2-pyrrolidone) in aqueous solution. J Appl Polym Sci 2002. [DOI: 10.1002/app.10047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mazi H, Zümreoğlu-Karan B, Güner A. Dextran-rare earth ion interactions. I. Dynamics in aqueous solutions. J Appl Polym Sci 2001. [DOI: 10.1002/app.1855] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Güner A, Kibarer G. The important role of thermodynamic interaction parameter in the determination of theta temperature, dextran/water system. Eur Polym J 2001. [DOI: 10.1016/s0014-3057(00)00152-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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28
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Effect of phenolic cosolutes on the main parameters, phase separation and theta temperature of dilute aqueous poly(N-vinyl-2-pyrrolidone) solutions. Eur Polym J 2001. [DOI: 10.1016/s0014-3057(00)00106-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Çatiker E, Güner A. Unperturbed dimensions and the theta temperature of dextran in ethylene glycol solutions. Eur Polym J 2000. [DOI: 10.1016/s0014-3057(99)00299-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Alencar de Queiro AA, Gallardo A, Román JS. Vinylpyrrolidone-N,N'-dimethylacrylamide water-soluble copolymers: synthesis, physical-chemical properties and proteic interactions. Biomaterials 2000; 21:1631-43. [PMID: 10905405 DOI: 10.1016/s0142-9612(00)00024-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The radical copolymerization of N-vinyl-2-pyrrolidone (NVP) with N,N'-dimethylacrylamide (DMAm) has been studied. The copolymer compositions were determined from 1H-NMR. The radical reactivity ratios for DMAm (M1) and VP (M2) were found to be r1 = 2.232 and r2 = 0.186. An analysis of the water vapor absorption isotherms as a function of the lactam content in the copolymer is reported. It was observed that the water vapor absorption decreases with increasing VP content in the copolymer and show anomalous diffusion behavior with increasing temperature due to the coupling of diffusion and polymer relaxation mechanisms. From the water vapor sorption data the Arrhenius activation parameter (ED) and enthalpy of sorption (deltaH S) were determined. The activation parameters are found to follow the conventional trend. The poly(DMAm-co-VP) copolymers exhibited a decreased critical solution temperature (LCST) in proportion to their lactam content. Contact angle data were evaluated for the determination of surface free energy components (gamma d SV, gamma P SV and gamma SV) of the synthesized polymers. The dispersion force component (gamma d SV) of copolymers increased only slightly with the VP content whereas the polar force component (gamma P SV) decreased with the lactam content. No dependence was observed between the surface free energy (gamma SV) and copolymer compositions. The complex formation between bovine serum albumin (BSA) and the VP-DMAm copolymers in water was studied by fluorescence spectroscopy. It was found that the copolymers bind to BSA non-specifically on the surface. Phase separation was not observed after addition of copolymers to BSA solutions at pH higher or lower than isoelectric point of BSA.
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Affiliation(s)
- A A Alencar de Queiro
- Departamento de Fisica e Química, Instituto de Ciências, Escola Federal de Engenharia de Itajubá, MG, Brazil.
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Chen CW, Tano D, Akashi M. Colloidal Platinum Nanoparticles Stabilized by Vinyl Polymers with Amide Side Chains: Dispersion Stability and Catalytic Activity in Aqueous Electrolyte Solutions. J Colloid Interface Sci 2000; 225:349-358. [PMID: 11254272 DOI: 10.1006/jcis.2000.6731] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Colloidal platinum nanoparticles were prepared by ethanol reduction of PtCl(6)(2-) in the presence of poly(N-vinylformamide) (PNVF), poly(N-vinylacetamide) (PNVA), or poly(N-vinylisobuty-ramide) (PNVIBA). The effects of molecular weight and molar ratio of monomeric unit/Pt on the particle sizes and size distributions were characterized by transmission electron microscopy and UV-visible spectroscopy. The flocculation behavior of the polymer-stabilized colloidal Pt nanoparticles was studied with respect to the effects of temperature, addition of inorganic salts, and composition of the mixed solvents. The dispersion stability of the platinum colloids stabilized by poly(N-isopropylacrylamide) (PNIPAAm) and poly(vinylpyrrolidone) (PVP) was also examined. The sequence of polymer-stabilized platinum colloids in increasing order of dispersion stability was found to be PNIPAAm-Pt<PNVIBA-Pt<PVP-Pt<PNVA-Pt<PNVF-Pt. Anions of the added salts played an essential role in reducing the dispersion stability and sulfates were more efficient at promoting flocculation than chlorides. The PNVF-Pt colloids did not show any critical flocculation point (temperature or salt concentration) under employed conditions, owing to the strongly hydrophilic nature of PNVF chains. The catalytic activity of PNVF-Pt colloids for hydrogenation of allyl alcohol in 0.8 M Na(2)SO(4) solution was the same as that in pure water. Copyright 2000 Academic Press.
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Affiliation(s)
- Chun-Wei Chen
- Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan
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