A Calorimetric Investigation of Moisture in Textile Fibers<sup>1a</sup>

Magne, Frank C.; Portas, H. J.; Wakeham, Helmut

doi:10.1021/ja01200a015

Cited by 88 publications

(27 citation statements)

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“…In some studies (Simpson and Barton 1991;Zauer et al 2014;Zelinka et al 2012), it is stated that this method is more correct as it does not assume any specific value of the melting enthalpy. However, all studies show that the melting enthalpies determined are close to the generally accepted value of 333.6 J/g (Magne et al 1947;Nelson 1977;Zauer et al 2014) as shown in Fig. 4, considering the experimental uncertainties (small sample masses, high/low temperature ramping rates, heat flow accuracy, etc.)…”

Section: Differential Scanning Calorimetrysupporting

confidence: 77%

“…As cell wall water is tightly associated with the chemical constituents, it will not exhibit a phase change at least down to -70°C (Berthold et al 1994). This was first used by Magne et al (1947) to determine the amount of cell wall water in water-saturated textile fibres (cotton, rayon, nylon, glass fibres) by measuring the energy for freezing water at -4°C. Since then, DSC techniques have been used to determine cell wall water within, for example, pulp and paper fibres (Maloney 2000;Nelson 1977;Park et al 2006;Weise et al 1996), untreated wood (Simpson and Barton 1991;Zauer et al 2014;Zelinka et al 2012), and modified wood (Repellin and Guyonnet 2005;Zauer et al 2014).…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

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Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

2017

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Water plays a central role in wood research, since it affects all material properties relevant to the performance of wood materials. Therefore, experimental techniques for characterising water within wood are an essential part of nearly all scientific investigations of wood materials. This review focuses on selected experimental techniques that can give deeper insights into various aspects of water in wood in the entire moisture domain from dry to fully water-saturated. These techniques fall into three broad categories: (1) gravimetric techniques that determine how much water is absorbed, (2) fibre saturation techniques that determine the amount of water within cell walls, and (3) spectroscopic techniques that provide insights into chemical wood-water interactions as well as yield information on water distribution in the macro-void wood structure. For all techniques, the general measurement concept is explained, its history in wood science as well as advantages and limitations.

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Section: Differential Scanning Calorimetrysupporting

confidence: 77%

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

2017

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“…wet) are: À123 JÁg À1 for cellulose(am), À28 JÁg À1 for cellulose I(cr), À22 JÁg À1 for cellulose II(cr), and À28 JÁg À1 for cellulose III(cr). We note that there is a body of evidence in the literature [15,[60][61][62][63] that the absorption of water occurs substantially in the amorphous regions of cellulose samples. Thus, it is of interest that the values of D hyd H Ã w (0 ?…”

Section: Reactionmentioning

confidence: 87%

A thermodynamic investigation of the cellulose allomorphs: Cellulose(am), cellulose Iβ(cr), cellulose II(cr), and cellulose III(cr)

Goldberg

Schliesser

Mittal

et al. 2015

The Journal of Chemical Thermodynamics

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a b s t r a c tThe thermochemistry of samples of amorphous cellulose, cellulose I, cellulose II, and cellulose III was studied by using oxygen bomb calorimetry, solution calorimetry in which the solvent was cadoxen (a cadmium ethylenediamine solvent), and with a Physical Property Measurement System (PPMS) in zero magnetic field to measure standard massic heat capacities C p;w over the temperature range T = (2 to 302) K. The samples used in this study were prepared so as to have different values of crystallinity indexes CI and were characterized by X-ray diffraction, by Karl Fischer moisture determination, and by using gel permeation chromatography to determine the weight average degree of polymerization DP w . NMR measurements on solutions containing the samples dissolved in cadoxen were also performed in an attempt to resolve the issue of the equivalency or non-equivalency of the nuclei in the different forms of cellulose that were dissolved in cadoxen. While large differences in the NMR spectra for the various cellulose samples in cadoxen were not observed, one cannot be absolutely certain that these cellulose samples are chemically equivalent in cadoxen. Equations were derived which allow one to adjust measured property values of cellulose samples having a mass fraction of water w H 2 O to a reference value of the mass fraction of water w ref . The measured thermodynamic properties (standard massic enthalpy of combustion D c H w , standard massic enthalpy of solution D sol H w , and C p;w ) were used in conjunction with the measured CI values to calculate values of the changes in the standard massic enthalpies of reactionD r H Ã w , the standard massic entropies of reaction D r S Ã w , the standard massic Gibbs free energies of reaction D r G Ã w , and the standard massic heat capacity D r C p;w , for the interconversion reactions of the pure (CI = 100) cellulose allomorphs, i.e., cellulose(am), cellulose I(cr), cellulose II(cr), and cellulose II(cr), at the temperature T = 298.15 K, the pressure p = 0.1 MPa, and w H 2 O = 0.073. The '' ⁄ '' denotes that the thermodynamic property pertains to pure cellulose allomorphs. Values of standard massic enthalpy differences D T 0 H w , standard massic entropy differences D T 0 S w , and the standard massic thermal functionwere calculated from the measured heat capacities for the cellulose samples and for the pure cellulose allomorphs. The extensive literature pertinent to the thermodynamic properties of cellulose has been summarized and, in many cases, property values have been calculated or recalculated from previously reported data. The thermodynamic property data show that cellulose(am) is the least stable of the cellulose allomorphs considered in this study. However, due to the uncertainties in the measured property values, it is not possible to use these values to order the relative stabilities of the cellulose (I, II, and III) crystalline allomorphs with a reasonable degree of certainty. Nevertheless, http://dx.

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“…The clustering tendency of water molecules in polymer matrix is generally chracterized by the cluster function, G 11 /V 1 , or cluster size, 1+v 1 G 11 /V 1 . 16 (3) where v 1 and v 2 are the volume fractions of the water and polymer, respectively, V 1 , the molecular volume of water, a 1 , the activity of water vapor, and G 11 is the cluster integral. Applying eq 3 to the results of the sorption isotherms in Figure 1, the cluster size, Figure 4 shows that the cluster size of water in the copolymer membrane is larger than that in both homopolymer membranes, i.e., at low relative vapor pressures, the cluster size in 96/4 MMAjNVP is maximum and the clustering tendency in 73/27 becomes remarkable at relative vapor pressures higher than 0.…”

Section: Resultsmentioning

confidence: 99%

Characteristics of Water in Copoly(methyl methacrylate–N-vinylpyrrolidone) Membranes

Takizawa

Kinoshita

Nomura

et al. 1985

Polym J

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ABSTRACT:The characteristics of water in methyl methacrylate-N-vinylpyrrolidone (MMAINVP) copolymer membranes were studied. The sorption and permeation behavior and differential scanning calorimetric behavior of MMA/NVP copolymer-water systems contained two types of water in the copolymer membranes at relative vapor pressures up to ca. 0.9: water directly bound to polar NVP residues at low relative vapor pressures, i.e., the "tightly bound" water, and water associated in the vicinity of hydrophobic MMA residues forming multimolecular clusters at higher relative vapor pressures, i.e., "hydrophobic hydration" water. The latter was characterized by a rigid structure resulting in an increase in the shear modulus of the copolymer membrane at relative vapor pressure higher than 0.5. It is concluded that the cluster size or clustering tendency in MMAINVP membranes, i.e., the amount of hydrophobic hydration water in the copolymer, is enhanced by the presence of the proper amount ofNVP residues in the copolymers via enhancement of water uptake by the membranes.KEY WORDS Hydrophobic Hydration Water I Rigid Water Cluster I Sorption I Permeation I Shear Modulus I Copoly(methyl methacrylate-Nvinylpyrrolidone) I Several functional properties of a polymer such as mechanical strength and relaxation behavior, swelling and membrane permeation behavior are directly related to the manner in which the polymer interacts with water.

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A Calorimetric Investigation of Moisture in Textile Fibers^1a

Cited by 88 publications

References 1 publication

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

A thermodynamic investigation of the cellulose allomorphs: Cellulose(am), cellulose Iβ(cr), cellulose II(cr), and cellulose III(cr)

Characteristics of Water in Copoly(methyl methacrylate–N-vinylpyrrolidone) Membranes

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A Calorimetric Investigation of Moisture in Textile Fibers1a

Cited by 88 publications

References 1 publication

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

A thermodynamic investigation of the cellulose allomorphs: Cellulose(am), cellulose Iβ(cr), cellulose II(cr), and cellulose III(cr)

Characteristics of Water in Copoly(methyl methacrylate–N-vinylpyrrolidone) Membranes

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A Calorimetric Investigation of Moisture in Textile Fibers^1a