The Effects of Disaggregating Agents on the Stress-Strain Relationship for Wool Fibers

Crewter, W.G.

doi:10.1177/004051757204200202

Cited by 14 publications

(7 citation statements)

References 32 publications

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“…That is why, as we observed, the recovery process in the stretched wool fiber at room conditions was rather slow (Figs. [2][3][4][5].…”

Section: Discussionmentioning

confidence: 99%

“…In spite of many researches done to understand the mechanical properties of wool fibers, [1][2][3][4][5][6][7][8][9][10][11] some of which have resulted in the proposal of structural models, [1][2][3][4][5] only few studies have been devoted to the investigation of the recovery process. [12] There is no exact information about the velocity of this process; whether it depends on the extension levels; how long a complete recovery at room conditions takes; and how water influences this process.…”

Section: Introductionmentioning

confidence: 99%

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Recovery Process in Stretched Wool Fibers

Tsobkallo

Aksakal

Darvish

2010

Journal of Macromolecular Science, Part B

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The recovery process in stretched wool fibers at different strain levels ranging from 5% to 40% was investigated at room conditions for a long time, up to one year, and in water. The recovery process in stretched wool fibers is quite slow at room conditions; thus this slow recovery process causes quite high remaining deformation on the wool. The recovery process in the strain (ε) and logarithm time (log t) coordinates has a linear dependence in the wide time range that allows estimating the required time for a complete recovery. In contrast to the rather slow recovery process at room conditions, a complete recovery in water at room temperature was observed within approximately 30 s. Structural changes during the recovery processes at room conditions and in water were analyzed by an FTIR/ATR method. The influences of water content and new formations of hydrogen bonds in the recovery processes were examined. Slow recovery at room conditions was associated with the reorganization of the hydrogen bonds between microfibrills and matrix which results in formation of a new and rather stable structure. The absorption of water by the matrix phase causes the disruption of the strong hydrogen bonds holding the stretched form of the fiber and leads to a rapid recovery.

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“…That is why, as we observed, the recovery process in the stretched wool fiber at room conditions was rather slow (Figs. [2][3][4][5].…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Recovery Process in Stretched Wool Fibers

Tsobkallo

Aksakal

Darvish

2010

Journal of Macromolecular Science, Part B

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“…22a): crystalline IFs are embedded in an amorphous, water-sensitive matrix [105]. Several variations of this model have been used [106][107][108]110,164,168,169], and a review has critically evaluated the relevant models [109]. Present below are the essential elements of the two-phase model (rule of mixtures).…”

Section: Wool and Hairmentioning

confidence: 99%

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Wang

Yang

McKittrick

et al. 2016

Progress in Materials Science

660

474

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a b s t r a c tA ubiquitous biological material, keratin represents a group of insoluble, usually high-sulfur content and filament-forming proteins, constituting the bulk of epidermal appendages such as hair, nails, claws, turtle scutes, horns, whale baleen, beaks, and feathers. These keratinous materials are formed by cells filled with keratin and are considered 'dead tissues'. Nevertheless, they are among the toughest biological materials, serving as a wide variety of interesting functions, e.g. scales to armor body, horns to combat aggressors, hagfish slime as defense against predators, nails and claws to increase prehension, hair and fur to protect against the environment. The vivid inspiring examples can offer useful solutions to design new structural and functional materials.Keratins can be classified as a-and b-types. Both show a characteristic filament-matrix structure: 7 nm diameter intermediate filaments for a-keratin, and 3 nm diameter filaments for b-keratin.Both are embedded in an amorphous keratin matrix. The molecular unit of intermediate filaments is a coiled-coil heterodimer and that of b-keratin filament is a pleated sheet. The mechanical response of a-keratin has been extensively studied and shows linear Hookean, yield and post-yield regions, and in some cases, a high reversible elastic deformation. Thus, they can be also be considered 'biopolymers'. On the other hand, b-keratin has not been investigated as comprehensively. Keratinous materials are strain-rate sensitive, and the effect of hydration is significant.Keratinous materials exhibit a complex hierarchical structure: polypeptide chains and filament-matrix structures at the nanoscale, Progress in Materials Science 76 (2016) 229-318 Contents lists available at ScienceDirect Progress in Materials Sciencej o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p m a t s c i organization of keratinized cells into lamellar, tubular-intertubular, fiber or layered structures at the microscale, and solid, compact sheaths over porous core, sandwich or threads at the macroscale. These produce a wide range of mechanical properties: the Young's modulus ranges from 10 MPa in stratum corneum to about 2.5 GPa in feathers, and the tensile strength varies from 2 MPa in stratum corneum to 530 MPa in dry hagfish slime threads. Therefore, they are able to serve various functions including diffusion barrier, buffering external attack, energy-absorption, impact-resistance, piercing opponents, withstanding repeated stress and aerodynamic forces, and resisting buckling and penetration.A fascinating part of the new frontier of materials study is the development of bioinspired materials and designs. A comprehensive understanding of the biochemistry, structure and mechanical properties of keratins and keratinous materials is of great importance for keratin-based bioinspired materials and designs. Current bioinspired efforts including the manufacturing of quill-inspired aluminum composites, animal horn-inspired SiC composites, and feather-i...

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“…A capillary does not necessarily have to be a tubular, closed shape, but can be any confined space with respect to its surroundings. The matrix, which is the hair component most involved in the moisture sorption–desorption process, has been described as ‘chains of beads’ [15], the ‘grains’ being the Keratin Associated Proteins (KAPs) [16]. The confined space between these grains may, therefore, form the network of capillaries for water, as suggested in Figure 2 [16].…”

Section: Resultsmentioning

confidence: 99%

Learning from hair moisture sorption and hysteresis

Breakspear

Frueh

Neu

et al. 2022

Intern J of Cosmetic Sci

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Objective The process of moisture sorption and desorption by human hair was analysed for extracting hints on the hair structure. Methods The isotherms of moisture sorption and desorption by hair were recorded for untreated and chemically treated (permed and bleached) hair. Data of swelling were also considered. Results By examining the swelling and moisture sorption of keratin fibres, it is possible to conclude that hysteresis is quite improbably caused by capillary condensation. The mobility of the protein chains and the strength of the bonds binding water molecules to the active sites inside the matrix are proposed as causes instead. The concept of “breaking symmetry”, derived from moisture sorption– desorption data, and the method of evaluating this parameter, is proposed as a way of characterizing the chemical treatment of hair. The results show that bleaching produces a larger breaking of symmetry than perming, and this is suggested to be due to new hydrogen bonds, created as a result of the chemical treatment, replacing the original disulphide bonds, which are of different strength compared to the bonds of untreated hair. The quantitative sorption data matched well to the model of grains of matrix enveloped in layers of water molecules at increasing relative humidity, up to 100%. The analysis suggested that, aside from the glass transition event occurring at around 60%–70% relative humidity, there is another, less examined, transition occurring at around 30% relative humidity, assigned to the opening of the hair inner structure, and accommodation of more water molecules. Both transitions are reflected by corresponding changes in the fibre mechanical behaviour. Conclusion The moisture sorption–desorption by hair was shown to not only allow a quantitative differentiation among various cosmetic treatments of the hair but to also provide valuable information on the structure of the fibre.

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The Effects of Disaggregating Agents on the Stress-Strain Relationship for Wool Fibers

Cited by 14 publications

References 32 publications

Recovery Process in Stretched Wool Fibers

Recovery Process in Stretched Wool Fibers

Keratin: Structure, mechanical properties, occurrence in biological organisms, and efforts at bioinspiration

Learning from hair moisture sorption and hysteresis

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