Study of the structure transformation of wool fibers with Raman spectroscopy

Liu, Hongling; Yu, Weidong

doi:10.1002/app.23862

Cited by 47 publications

(31 citation statements)

References 10 publications

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“…In particular, the peak at lower wave numbers decreased in intensity and shifted to higher wave numbers. The amide III was particularly sensitive to changes in the protein secondary structure . Therefore, conformational modifications could explain the spectral changes observed, but no significant changes were observed in amide I, as should be when the protein secondary structural changes.…”

Section: Resultsmentioning

confidence: 86%

Chemical and physical modifications of electrospun keratin nanofibers induced by heating treatments

Varesano

Vineis

Tonetti

et al. 2014

J of Applied Polymer Sci

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In this study, we aimed to examine to study the effects of heating treatments on wool‐derived keratin nanofibers obtained by electrospinning. Interestingly, the keratin nanofibers did not lose their nanofibrous shape at high temperatures. On the contrary, the diameter of keratin nanofibers significantly decreased after heating. Even the chemical structure of the keratin was not significantly altered by heating, as observed by IR spectroscopy, except for a shoulder at 1720 cm−1 and the amide III band. The spectral feature changes matched the formation of crosslinking amide bonds between protein chains well. Moreover, for various applications, it is essential that nanofibers are stable in water. Heating treatments were carried out at different temperatures and times to assess what heating conditions gave the keratin nanofibers water stability. Finally, no significant changes in the thermal behavior were observed in the samples after heating treatments compared to the untreated keratin nanofibers; this was a sign of negligible or slight degradations of the protein chains. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40532.

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Section: Resultsmentioning

confidence: 86%

Chemical and physical modifications of electrospun keratin nanofibers induced by heating treatments

Varesano

Vineis

Tonetti

et al. 2014

J of Applied Polymer Sci

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“…Component peaks of this complex band were separated by a curve fitting method and then their absorbance values were calculated and normalized to the value of an internal standard peak. The peak at 1448 cm −1 , assigned to CH 2 scissoring mode, [8,16] was chosen as an internal standard.…”

Section: Methods For Spectroscopic Measurementsmentioning

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%

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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“…The stretching slenderization of wool fibers is a novel technique for improving the fineness of wool fibers 1. Our previous studies have demonstrated that the chemical mechanism of the technique is the breakage and reconstruction of some chemical bonds, especially hydrogen bonds and disulfide bonds in wool fibers 2, 3. Therefore, wool fibers should be pretreated with chemical reagents before the stretching slenderization process to weaken the chemical crosslinks and make the breakage of crosslinks easy.…”

Section: Introductionmentioning

confidence: 99%

Modeling the stress‐relaxation behavior of wool fibers

Liu

Hong

2008

J of Applied Polymer Sci

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The stress-relaxation behavior of wool fibers after a pretreatment with a chemical solution is particularly important for evaluating the efficiency of the pretreatment. In this study, three viscoelastic models, including the Maxwell, two Maxwell unit, and modified two Maxwell unit models, were established first. To verify the feasibility of the models, stress-relaxation experiments for wool fibers were performed. The wool fibers were pretreated with a sodium bisulfite solution (1 and 3%) at various temperatures (293, 298, 303, 308, 313, and 318 K). Then, the experimental values were fitted to the three models to obtain the rate constants of relaxation. The activation energy of the wool fibers was calculated with the Arrhenius equation. The results showed that the modified two Maxwell unit model provided the best fit for the experimental data of the wool fibers. The stress-relaxation process of the wool fibers could be divided into two stages, a rapid stage followed by a slow stage. The rapid relaxation of stress was attributed to the weak bonds in the wool fibers, and the following slow relaxation stage was attributed to strong bonds. The Arrhenius equation could describe the stress-relaxation process of the wool fibers very well. Furthermore, the activation energy decreased in the presence of sodium bisulfite.

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Study of the structure transformation of wool fibers with Raman spectroscopy

Cited by 47 publications

References 10 publications

Chemical and physical modifications of electrospun keratin nanofibers induced by heating treatments

Chemical and physical modifications of electrospun keratin nanofibers induced by heating treatments

Recovery Process in Stretched Wool Fibers

Modeling the stress‐relaxation behavior of wool fibers

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