40—the Heat of Wetting of Fibres

Bright, Norman F. H.; Carson, Travis D.; Duff, G. M.

doi:10.1080/19447025308662619

Cited by 14 publications

(9 citation statements)

References 10 publications

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“…Various models of passive knitted textiles exist and these can provide a starting point for modeling active knit textiles. Purely geometric, small deformation models of plain knit apparel fabrics have been developed over the last century [62][63][64][65][66][67][68][69][70][71][72][73][74]. More recently, models of knitted engineering materials (such as glass, steel, and carbon fiber) have been derived to predict the performance of engineering composites, which may improve mechanical performance (energy absorption, bearing and notched strengths, and fracture toughness) [75][76][77][78][79].…”

Section: Introductionmentioning

confidence: 99%

A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture

Abel¹,

Luntz²,

Brei³

2012

Smart Mater. Struct.

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Active knits are a unique architectural approach to meeting emerging smart structure needs for distributed high strain actuation with simultaneous force generation. This paper presents an analytical state-based model for predicting the actuation response of a shape memory alloy (SMA) garter knit textile. Garter knits generate significant contraction against moderate to large loads when heated, due to the continuous interlocked network of loops of SMA wire. For this knit architecture, the states of operation are defined on the basis of the thermal and mechanical loading of the textile, the resulting phase change of the SMA, and the load path

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Section: Introductionmentioning

confidence: 99%

A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture

Abel¹,

Luntz²,

Brei³

2012

Smart Mater. Struct.

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“…The ability to bind and absorb large amounts of water is one of the characteristics of wool fibers [ 13]. A relatively large number of .papers have examined the interaction of wool fibers with water using water vapor sorption isotherms [5, 14, 30, 32, 331 and basic calorimetric techniques [4,20,26]. Workers have established that part of the water sorbed on natural polymers such as keratin proteins and cellulose and silk fibroin has properties that are markedly different from free water.…”

mentioning

confidence: 99%

States of Water Sorbed on Wool as Studied by Differential Scanning Calorimetry

Sakabe

Ito

Miyamoto

et al. 1987

Textile Research Journal

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The states of water sorbed on Merino wool fibers, their histological components, and chemically modified wool fibers were investigated by differential scanning calorimetry (DSC) in order to elucidate the amount of bound water on wool fibers, the differences between the histological components of wool fibers, and the effect of polar groups on the states of water sorbed on wool fibers. For the sake of comparison, the states of water sorbed on cotton and silk were also examined. There may exist three different kinds of water sorbed on wool fibers, i.e., free water, freezing bound water, and nonfreezing bound water. The amount of bound water on wool fibers is larger than that on cotton yam and silk. The amount of bound water on cortical cells is about two times higher than that on cuticular cells. The amount of bound water on nonkeratinous cell components is about three times higher than that on keratinous cell components. The cell membrane complex plays an important role in water penetrating to wool fibers, but its contribution to the amount of bound water is negligible. The contribution of polar groups in wool fibers to the amount of bound water is not specific at high water contents, indicating that the peptide groups of the main chain play a significant role as water binding sites at high water contents.Many of excellent properties of wool as a textile fiber are more or less associated with the specific interactions of wool proteins with water. The ability to bind and absorb large amounts of water is one of the characteristics of wool fibers [ 13]. A relatively large number of .papers have examined the interaction of wool fibers with water using water vapor sorption isotherms [5, 14, 30, 32, 331 and basic calorimetric techniques [4, 20, 26]. Workers have established that part of the water sorbed on natural polymers such as keratin proteins and cellulose and silk fibroin has properties that are markedly different from free water. Many different works have substantiated this consideration [8, 10, 18; 19, 21, 22, 24, 34].On the other hand, wool consists of several histological components that are very different in chemical and physical properties [2,13,36]. It is important to elucidate the differences between these histological components and the functions of individual cell components. Numerous efforts have been devoted to this problem [2,11,12,36]. The accessibility of water molecules to individual histological components of wool has also been studied extensively from various points of view [6,7,23,27,28,29,36], but no study has reported so far on the states of water sorbed on the individual histological components of wool fibers.Recently, Nakamura et al. [22] pointed out that there are three different kinds of sorbed water on polymer: free water, freezing bound water, and nonfreezing bound water, based on the studies using differential scanning calorimetry (DSC). Recent developments in microcalorimetry by DSC enable us to evaluate the contents of free and bound water on polymers [22]. It is of interest to exam...

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“…In our experience with the three fibers, the proteins are much less sensitive to high temperature drying than cellulose. Wool lteratin can be dried in vacuum up to 80' C without affecting its heat of wetting (25), and i t shows no hysteresis in its heat of wetting curve (2). Probably sillt fibroin could also be heated nearly t o this temperature without changing its adsorption properties, because on drying a t 100" C it shows only a small hysteresis in its heat of wetting curve (1 hysteresis is in the opposite direction to that observed for cellulose (5).…”

Section: A Comparison Of Cellulose and The Fibroz~s Proteinsmentioning

confidence: 99%

The Thermodynamic Properties of the System Cellulose – Water Vapor

Morrison¹,

Dzieciuch²

1959

Can. J. Chem.

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The heats of wetting by water of cotton cellulose containing various amounts of adsorbed and desorbed water were measured. These measurements together with those of the water vapor sorption isotherm were used to calculate the integral and differential enthalpies, free energies, and entropies of adsorption. Irreversible effects were avoided by vacuum-drying all samples a t room temperature. The dilfercntial enthalpy values suggest hydrogen bonding. The differential entropies are explained in terms of changes in both the adsorbate andThe surface area of the cellulose is calculated by applying the Brunauer-Em~nett-Teller and Harkins-Jura equations to the adsorption isotherm. The changes in the differential enthalpies and entropies of adsorption follow the same sequence as the changes in film formation given by the surface area calculations.No hysteresis was observed in the heats of wctting of adsorbed and desorbed samples. I t is concluded that the hysteresis of the sorption isotherm is an entropy phenomenon. This supports Barkas' explanation of hysteresis in terms of plastic deformation of a gel. INTRODUCTIONMeasurement of the amounts, the vapor pressures, and the energies involved when water vapor is added to and removed froin fibrous natural polyiners have made it possible to calculate in detail the therinodynamic properties of the systeins silk fibroin -water vapor and wool keratiil-water vapor (1, 2, 3). T h e present report includes the saine kind of ineasureinents on the system cellulose -water vapor.Wahba also made similar ineasuremellts on the cellulose -water vapor system (4). However, we believe that Wahba's drying procedures introduce a n irreversible effect. A similar but larger effect is sho\vi~ in the work of Argue and Maass ( 5 ) , who inade the first detailed measurements of the heats of wetting of cellulose by water.Babbitt (6) made a coinprehe~lsive a~lalysis of the adsorption isotherm of the cellulose -water vapor system and was the first to apply the Brunauer, Emmett, and Teller adsorptioil isotherin equatioil (7) t o this system. In the present work, surface area measurements have assisted us in interpreting the thermodynamic properties. E X P E R I M E N T A LCalori~netric measureinent of the heats of wettin:: by liquid water of cellulose equili--.

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40—the Heat of Wetting of Fibres

Cited by 14 publications

References 10 publications

A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture

A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture

States of Water Sorbed on Wool as Studied by Differential Scanning Calorimetry

The Thermodynamic Properties of the System Cellulose – Water Vapor

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