II—Intrinsic viscosity and light scattering measurements on poly(ethylene oxide), poly(styrene oxide) and poly(t-butyl ethylene oxide)

Allen, G. C.; Booth, Colin; Hurst, S.J.; Jones, Malcolm N.; Price, Colin

doi:10.1016/0032-3861(67)90039-0

Cited by 77 publications

(8 citation statements)

References 15 publications

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“…Many different solvent systems have been used over a temperature range of 25−72 °C. Characteristic ratios C ∞ for high molecular weight samples, given by where 〈 R 2 〉 0 is the unperturbed mean-square end-to-end distance, 〈 R g 2 〉 0 is the unperturbed mean-square radius of gyration, n is the number of skeletal bonds, m 0 is the mean molecular weight per skeletal bond, and l 2 (2.1436 Å 2 for POE) denotes the mean-square bond length, typically range from 4 to 5.6. − Traditional rotational isomeric state (RIS) calculations for unperturbed chains have yielded C ∞ of 4.2 (60 °C) and 5.0 and 5.2 (30 °C). , The temperature coefficients for chain dimensions, d ln〈 R 2 〉 0 /d T , were calculated 9,19 to be in the range of 0.12 × 10 -3 to 0.74 × 10 -3 K -1 . Our recent quantum chemistry based third-order RIS model for POE, which was parameterized independent of experimental data for the polymer chain dimensions, yields values of C ∞ = 5.0 and d ln〈 R 2 〉 0 /d T = 0.11 × 10 -3 K -1 .…”

Section: Introductionmentioning

confidence: 99%

“…Characteristic ratios C ∞ for high molecular weight samples, given by where 〈R 2 〉 0 is the unperturbed mean-square end-to-end distance, 〈R g 2 〉 0 is the unperturbed mean-square radius of gyration, n is the number of skeletal bonds, m 0 is the mean molecular weight per skeletal bond, and l 2 (2.1436 Å 2 for POE) denotes the mean-square bond length, typically range from 4 to 5.6. [8][9][10][11][12][13][14][15][16][17] Traditional rotational isomeric state (RIS) calculations for unperturbed chains have yielded C ∞ of 4.2 (60 °C) 18 and 5.0 and 5.2 (30 °C). 9,19 The temperature coefficients for chain dimensions, d ln〈R 2 〉 0 /dT, were calculated 9,19 to be in the range of 0.12 × 10 -3 to 0.74 × 10 -3 K -1 .…”

Section: Introductionmentioning

confidence: 99%

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Conformations and Structures of Poly(oxyethylene) Melts from Molecular Dynamics Simulations and Small-Angle Neutron Scattering Experiments

et al. 1996

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An ensemble of H(CH2OCH2)12H chains has been studied by molecular dynamics simulations as both melt chains and unperturbed phantom chains as a model system to investigate condensed phase effects on chain conformations of poly(oxyethylene) (POE). In addition, conformations of high molecular weight POE chains in the melt have been determined by small-angle neutron scattering (SANS) experiments over a temperature range of 347-459 K. Our simulations show that POE chains in the melt are more extended than the phantom chains which represent the unperturbed chains in Θ solution. Moreover, the melt chains exhibit a negative temperature coefficient of chain dimensions in contrast to a positive value for the phantom chains. The difference in chain dimensions and the difference in the temperature dependence of chain dimensions between melt and phantom chains are corroborated by the results of our SANS measurements when they are compared with experimental results for POE chains in Θ solution. We attribute these significant deviations in conformational properties of POE chains in the melt from those of unperturbed ideal chains to condensed phase effects, similar to those found in 1,2-dimethoxyethane (DME), a dimer molecule of POE, from both experiments and simulations. That is, simulations show that the population of the C-C-O gt conformation is greater in melt chains than in the phantom chains, while the C-C-O g ( gpopulations are much smaller in the melt, the latter effect largely accounting for the more extended dimensions of the melt chains. As in DME, the conformationdependent intermolecular polar attractions (O‚‚‚H interactions, for example) account for these condensed phase effects, which become more pronounced at lower temperatures. Such intermolecular polar attractions in POE melts also result in increased interatomic packing order, but do not appear to enhance the intermolecular orientational order when compared to simulation results for polymethylene melts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conformations and Structures of Poly(oxyethylene) Melts from Molecular Dynamics Simulations and Small-Angle Neutron Scattering Experiments

et al. 1996

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“…The values of Mv for PEG samples were estimated from [ry] obtained in benzene at 25°C. 23 The concentrations of various permeants were determined by the methods summarized in Table II.…”

Section: Diffusive Permeabilitymentioning

confidence: 99%

Permeability through Cellulose Membranes Grafted with Vinyl Monomers in a Homogeneous System I. Diffusive Permeability through Acrylonitrile Grafted Cellulose Membranes

Nishioka

Watase

Arimura

et al. 1984

Polym J

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ABSTRACT:The homogeneous graft copolymerization of acrylonitrile onto cellulose was carried out in a dimethyl sulfoxide (DMSO)-paraformaldehyde solvent system. Three kinds of membranes were prepared: higher grafting efficiency membranes (H-GE membrane), lower grafting efficiency membranes (L-GE membrane), and blended membranes. The diffusive permeability of solutes through the water-swollen membranes was investigated. The permeability and microphase separated structure depended remarkably on the kind of membrane. Permeability through the H-GE membranes increased with increasing polyacrylonitrile content and leveled off, but that through the L-GE and blended membranes decreased. Permeability through the H-GE membranes was superior to that through the cellulose membrane cast from the DMSO solution of cellulose. However, the good permeability through the H-GE membranes could not be explained by the difference in water content of membranes.KEY The commercial regenerated cellulose membrane, Cuprophan, produced by the cuprammonium process has been widely used as a hemodialysis membrane owing to its good solute permeability and mechanical strength. However, it is also recognized that the diffusive permeability of solutes of molecular weight ranging from hundreds to thousands is not so good. mechanical strength of the membranes. To produce membranes of good permeability and mechanical strength, many studies have been carried out on amphiphilic copolymer membranes having the proper composition of hydrophilic and hydrophobic regions which function to control solute permeation and support the membrane, respectively. 4 -10

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“…Average molecular weights were obtained from viscometry with the following equation [ ] = 3.97 X 10-4 °'69 appropriate for benzene solutions at 25 °C. 24 Isotactic poly(methyl methacrylate) was synthesized by the method described by Goode25 using phenylmagnesium bromide as initiator and toluene as solvent at 10 °C. The polymer was fractionated by precipitation at room temperature in the solvent-nonsolvent system benzene-methanol.…”

Section: Methodsmentioning

confidence: 99%

Molecular weight effect on the miscibility of poly(ethylene oxide) and isotactic poly(methyl methacrylate) in their blends

Marco¹,

Fatou²,

Gómez³

et al. 1990

Macromolecules

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II—Intrinsic viscosity and light scattering measurements on poly(ethylene oxide), poly(styrene oxide) and poly(t-butyl ethylene oxide)

Cited by 77 publications

References 15 publications

Conformations and Structures of Poly(oxyethylene) Melts from Molecular Dynamics Simulations and Small-Angle Neutron Scattering Experiments

Conformations and Structures of Poly(oxyethylene) Melts from Molecular Dynamics Simulations and Small-Angle Neutron Scattering Experiments

Permeability through Cellulose Membranes Grafted with Vinyl Monomers in a Homogeneous System I. Diffusive Permeability through Acrylonitrile Grafted Cellulose Membranes

Molecular weight effect on the miscibility of poly(ethylene oxide) and isotactic poly(methyl methacrylate) in their blends

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