Characterization of poly(N-vinyl-2-pyrrolidone)s with broad size distributions

Knappe, Patrick; Bienert, Ralf; Weidner, Steffen M.; Thünemann, Andreas F.

doi:10.1016/j.polymer.2010.02.039

Cited by 38 publications

(31 citation statements)

References 32 publications

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“…This finding demonstrates that the A4F separates the PAA molecules efficiently from small to large radii. A comparable separation has been found recently for poly(vinyl pyrrolidone)s with broad size distribution 16…”

Section: Resultssupporting

confidence: 87%

“…SAXS measurements for the nine fractions were detected in a q range of 0.06–6.00 · nm −1 by merging the scattering curves measured with a Kratky‐type camera in a capillary15 and with a synchrotron setup in a levitator 10, 11. This combination of two SAXS instruments for high data quality of polymers at low concentration has been introduced recently 16. Note that the Kratky‐type camera produces data online, whereas the levitated droplet method can only produce data offline.…”

Section: Resultsmentioning

confidence: 99%

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Poly(acrylic acid): A Combined Analysis with Field‐Flow Fractionation and SAXS

Knappe

Bienert

Weidner

et al. 2010

Macro Chemistry & Physics

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Polyelectrolytes such as PAA and its salts are widely used, but are notoriously difficult to characterize due to their polyelectrolyte properties and broad molecular mass distributions. In this paper, we report on a new PAA analysis by combining asymmetrical flow field‐flow fractionation and an advanced SAXS technique using an acoustic levitator to minimize background scattering. The proof‐of‐principle is demonstrated with a mixture of three standard PAAs with different molecular masses. Detailed information on the PAA fractions is available on radii of gyration, polymer contour lengths, and coil conformation. Our method is expected to be applicable for a wide range of water‐soluble synthetic and natural polymers and ideal for molecular masses of 5 × 103–2 × 105 g · mol−1. magnified image

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Poly(acrylic acid): A Combined Analysis with Field‐Flow Fractionation and SAXS

Knappe

Bienert

Weidner

et al. 2010

Macro Chemistry & Physics

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“…If the used calibration standard shows different salt‐dependent behavior than the sample, only apparent diffusion coefficients will be obtained. In this case, the AF‐FFF results can be corrected by implementing an absolute detector, such as MALS detection57 or online SAXS 58–60. Also coupling of multiple detectors yields structural information as derived from power law behavior 61.…”

Section: Discussionmentioning

confidence: 99%

Ion Effects in Field‐Flow Fractionation of Aqueous Colloidal Polystyrene

Lang¹,

Eslahian²,

Maskos

2012

Macro Chemistry & Physics

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We discuss the effect of electrolytes on retention of aqueous colloidal polystyrene particles in asymmetrical flow (AF‐FFF) and thermal field‐flow fractionation (ThFFF). In both FFF subtechniques, interparticle interaction leads to non‐ideal fractionation behavior, which can result in a sample load dependency. Electrostatic repulsion is reduced with increasing electrolyte concentration, resulting in a pronounced increase of retention. At higher salinities, hydrophobic interactions dominate, thus applications of AF‐FFF under physiological conditions are limited. In ThFFF, also the separation mechanism of thermophoresis is affected by ionic shielding and experimental data are in accordance with recent theoretical models of thermophoresis.

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“…PVP had a viscosity characterized by a K‐value of 90, determined according to the method of Fikentscher . The number‐averaged molecular weight of this PVP is of the order of 1.4 × 10 6 g mol −1 with a dispersity of the order of 4.3 . The low‐molar‐mass fluids were NMP (solvent) and glycerol (non‐solvent) and were also used as received.…”

Section: Methodsmentioning

confidence: 99%

Fabrication of membranes of polyethersulfone and poly(N‐vinyl pyrrolidone): influence of glycerol on processing and transport properties

Handge

Gronwald²,

Weber³

et al. 2020

Polymer International

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In this study, we focus on membranes of polyethersulfone and poly(N-vinyl pyrrolidone) and elucidate the influence of composition on the rheological, diffusion and precipitation properties of solutions which are used for membrane preparation via a non-solvent-induced phase separation process. The low-molar-mass component of the solution is a mixture of the solvent N-methyl-2-pyrrolidone and the non-solvent glycerol. Cloud point, viscosity and diffusion measurements as well as precipitation experiments were performed in order to achieve a comprehensive understanding of the time dependence of the precipitation process. The addition of glycerol yields an increase of viscosity and a stronger tendency for demixing. The enhanced tendency for demixing causes a more rapid precipitation process. The average relaxation time of the solution as a function of glycerol concentration follows a similar trend to its viscosity. The increase of viscosity is associated with the increase of the monomeric friction coefficient. Two diffusive processes with clearly separated time scales appear in dynamic light scattering experiments in the presence of glycerol. This phenomenon is discussed taking into account the phase behaviour of the solution and the quality of the solvent. The addition of glycerol yields a lower pure water permeance whereas the molecular weight cut-off is not altered in the ultrafiltration range.

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Characterization of poly(N-vinyl-2-pyrrolidone)s with broad size distributions

Cited by 38 publications

References 32 publications

Poly(acrylic acid): A Combined Analysis with Field‐Flow Fractionation and SAXS

Poly(acrylic acid): A Combined Analysis with Field‐Flow Fractionation and SAXS

Ion Effects in Field‐Flow Fractionation of Aqueous Colloidal Polystyrene

Fabrication of membranes of polyethersulfone and poly(N‐vinyl pyrrolidone): influence of glycerol on processing and transport properties

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