Glass Transition Temperature of Wool as a Function of Regain

Wortmann, Franz; Rigby, B.J.; Phillips, D. G.

doi:10.1177/004051758405400102

Cited by 79 publications

(46 citation statements)

References 12 publications

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“…The presence of a single transition temperature T g for the keratinwater system has been shown by Wortmann et al 43 to obey the Fox equation quoted above and certainly supports the proposal of the two polymers of water and keratin forming a compatible interpenetrating network of two polymeric systems. It should be also noted that the effectiveness of the hydrophobic interactions between the ␣-helices of the helical rod domains in the IFs requires a continuous network of water molecules.…”

Section: The Keratin-water Systemsupporting

confidence: 77%

Natural protein fibers

Feughelman

2001

J of Applied Polymer Sci

114

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Alpha keratin fibers (hairs, wools, quills, and other mammalian appendages) together with fibroin fibers such as silks and spiders webs are all highly extensible fibrous proteins for which the mechanical properties are of primary importance both to the animal from which they originate and their ultimate application by man. Similarly, the collagens are highly inextensible fibrous proteins, which form the major component of mammalian skin and connecting structures such as tendons. All these fibrous proteins are biological polymers of polypeptide chains for which the mechanical and allied physical properties, such as water absorption, relate to both their macrostructure and their molecular and near-molecular structure. Because of both their commercial application and their relatively complex structure at the molecular and near-molecular level, interpretation of the physical properties of ␣-keratin fibers represents the main component of this presentation. The mechanical properties of ␣-keratin fibers are primarily related to the two components of the elongated cortical cells, the highly ordered intermediate filaments (microfibrils) which contain the ␣-helices, and the matrix in which the intermediate filaments are embedded. The matrix consists of globular proteins plus water, the content of the latter being dependent on the fibers environment. The Extended Two-Phase Model (ETPM) has been developed and results in a detailed coverage of the bulk mechanical properties of ␣-helical fibers in terms of their known molecular and near-molecular structure. The inextensible protein fibers, the collagens and fibroins, are also briefly discussed in terms of the relationship between mechanical properties and the structure of these fibers.

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Section: The Keratin-water Systemsupporting

confidence: 77%

Natural protein fibers

Feughelman

2001

J of Applied Polymer Sci

114

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“…Danilatos observed that even at high frequencies, equivalent to short relaxation times, no upper plateau value for the modulus is reached and that the part of the relaxation curve experimentally accessible spans considerably more than the expected nine decades of time. This can be related to the appearance of highly mobile water in the structure of the fiber [15,21] when the glass transition temperature drops below 20 ~ at a water content around 20 0/0 [22]. Consequently the relaxation behaviour of the wool fibers in water was not included in the present analysis, but is in detail discussed elsewhere [15].…”

Section: Discussionmentioning

confidence: 99%

The viscoelastic properties of wool and the influence of some specific plasticizers

Wortmann¹

1987

Colloid & Polymer Sci

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Abstract:The relaxation behaviour of Lincoln wool fibres in water and in three short chain aliphatic alcohols was measured. Applying a two phase model including a relaxation function based on a log-normal distribution of relaxation times a good systematic description of the data was found. The application of the model to the relaxation curves of wool fibers in the alcoholic media showed the invariance of the shape of the relaxation function, its shift on the log-time scale and the change of the elastical properties of the morphological components of the wool fibre depending on the aliphatic chain length of the alcohols. The importance of the apolar interactions for the elastic and viscoelastic properties of the morphological phases in the wool fibre is discussed.

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“…Under dry status, it was reported that the crystalline phase of α-keratin hair fiber (e.g., wool) accounts for 25%~30% of the whole fiber volume indicated by infrared and XRD data [30]. Under wet status, the high-sulfur protein, high-glycine tyrosine proteins, non-helical water penetrable materials, and the absorbed water in hair are all considered an amorphous matrix.…”

Section: Introductionmentioning

confidence: 99%

Shape Memory Investigation of α-Keratin Fibers as Multi-Coupled Stimuli of Responsive Smart Materials

Xiao

Gui

et al. 2017

Polymers

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Like the water responsive shape memory (SM) effect of β-keratin bird feathers, α-keratin hairs either existing broadly in nature are found responsive to many types of coupled stimuli in SM behaviors. In this article, α-keratin hairs were investigated for the combined stimuli of thermo-solvent, solvent-solvent, and UV (radiation)-reductant sensitive SM abilities. The related netpoints and switches from the hair molecular networks were identified. The experimental results showed that α-keratin hairs manifested a higher ability of shape fixation under thermal stimulus followed with the stimuli of solvent and UV-radiation. Shape recovery from the hair with a temporarily fixed shape showed a higher recovery ability using solvent than the stimuli of heat and UV-radiation. The effects of coupled stimuli on hair's shape fixation and recovery and on variations of the crystal, disulfide, and hydrogen bonds were studied systematically. A structural network model was thereafter proposed to interpret the multi-coupled stimuli sensitive SM of α-keratin hair. This original study is expected to provide inspiration for exploring other natural fibers to reveal related smart functions and for making more types of remarkable adapted synthetic materials.

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Glass Transition Temperature of Wool as a Function of Regain

Cited by 79 publications

References 12 publications

Natural protein fibers

Natural protein fibers

The viscoelastic properties of wool and the influence of some specific plasticizers

Shape Memory Investigation of α-Keratin Fibers as Multi-Coupled Stimuli of Responsive Smart Materials

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