Calorimetric determination of porosity and pore size distribution (PSD): Effect of heat on porosity, pore form, and PSD in water-saturated polyacrylonitrile fibers

Homshaw, L. G.

doi:10.1016/0021-9797(81)90266-6

Cited by 25 publications

(8 citation statements)

References 9 publications

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“…Also the DSC method uses water as a probe molecule to derive PSD in the fiber network. This technique reports on the melting curves of frozen water captured in the fiber structure in polyacrylonitrile fibers (Homshaw 1981) and in pulp fibers (Maloney et al 1998a, b) and is commonly referred to as thermoporosimetry or DSC cryoporometry. The same principle has been used on paper to derive PSD with NMR cryoporometry (Furó and Daicic 1999).…”

Section: Pulp Porosimetrymentioning

confidence: 99%

NMR cryoporometry to study the fiber wall structure and the effect of drying

et al. 2009

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NMR cryoporometry has been used for investigating the porosity changes of bleached wood pulp upon drying. This NMR method follows the same principles as thermoporosimetry, which has been used for the same purpose during the last decade and makes it possible to investigate porous material in the water-swollen state. In this study bleached softwood kraft pulp was exposed to a series of drying procedures where the decrease in porosity within the fiber cell wall could be characterized for pore radii below 100 nm. This decrease in porosity is called hornification, which is an irreversible collapse of the fiber wall structure during drying and results in decreased uptake of water and reduced swelling of the fiber upon rewetting. Our results have been compared to the traditionally used water retention value (WRV) and correlates well with these. Furthermore, this NMR method could show the reduction of hornification when adsorbing the hemicellulose glucuronoxylan to the fiber.

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Section: Pulp Porosimetrymentioning

confidence: 99%

NMR cryoporometry to study the fiber wall structure and the effect of drying

et al. 2009

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“…By combining Laplace's equation, which defines the conditions of dynamic equilibrium, with the Gibbs-Duhem equation, which defines the conditions of thermodynamic equilibrium, Brun et al (1977) and Homshaw (1981) (Ishikiriyama et al, 1995) for the boundary tension between ice and water y and 0 rad for the contact angle Q . The abscissa of the thermogram, representing temperature, may be converted into the pore radius using Eq.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of dialysis membranes using a tortuous pore model

Kokubo

Sakai

1998

AIChE Journal

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“…The crystals of the swelling agent are formed successively according to their size, so that from the course of the cooling curve a crystal size spectrum H(Dk) and H(dc), respectively, can be calculated [5]. With the help of DSC [1,26,27], the differentiated cooling curve d~ ~ dmi dATi dATi (3) can be obtained immediately (Fig. 2).…”

Section: Methods For Studying the Freezing Process In Swollen Networkmentioning

confidence: 99%

“…The mean pore dimensions and their distribution could be determined by studying the phase transition liquid-solid (solid-liquid) in porous materials (glass, building materials, ion exchanger, soils, PAN-fibres) depending on time [2,3,[6][7][8][9][10]. Investigations on aqueous polyacrylic acid/polyvinyl alcohol gels [11,12], on polystyrene networks swollen in naphthalene [4] and on rubbers swollen in benzene [13][14][15][16][17][18] showed a freezing point depression in a network polymer depending on the cross-linking density v. The crystal dimension Dk is assumed to be equal to the distance between the junction points in the swollen state de.…”

Section: At-z Tslo Asl (La) Lmentioning

confidence: 99%

Characterization of polymer networks by measurements of the freezing point depression

Arndt

Zander

1990

Colloid & Polymer Sci

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Based on the phenomenon of freezing point depression of a solvent by AT, experimental evidence is presented to show that the distance between the junction points can be calculated from AT. Direct measurements of the temperature-time-curve of the cooling network and the Differential Scanning Calorimetry offer the determination of zl T. Except the mean distances dc in dependence on cross-linking density, swelling degree, and other network parameters, the distribution of the distance between the junction points H(dc) can be determined, which allows conclusions on the course of cross-linking reaction. This paper attempts to give experimental evidence of influences of the breadth of H(dc) on application-relevant properties.

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Calorimetric determination of porosity and pore size distribution (PSD): Effect of heat on porosity, pore form, and PSD in water-saturated polyacrylonitrile fibers

Cited by 25 publications

References 9 publications

NMR cryoporometry to study the fiber wall structure and the effect of drying

NMR cryoporometry to study the fiber wall structure and the effect of drying

Evaluation of dialysis membranes using a tortuous pore model

Characterization of polymer networks by measurements of the freezing point depression

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