The effects of stretching on wool fibres as monitored by FT-Raman spectroscopy

Church, Jeffrey S.; Corino, Gary L.; Woodhead, Andrea L.

doi:10.1016/s0022-2860(97)00227-5

Cited by 39 publications

(35 citation statements)

References 8 publications

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“…We also failed to detect a significant change with applied strain in the structure of the amide bands. Again, this contrasts with wool 44 and in silk, 26 in which strain is associated with a loss of a-helix and with a recent study on synthetic elastin hydrogels, 45 which reports a downward shift in frequency for the amide I band and an increase in frequency for the amide III band, interpreted as an increase in a-helical content with strain. It may be that in the fibrous material the strain is carried by the b-structures where there is sufficient dynamic freedom to accommodate substantial strain without overall changes in secondary structure.…”

contrasting

confidence: 79%

The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy

2008

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Raman microspectroscopy has been used to investigate the structure of alpha-elastin and fibrous elastin from ligament and aorta, and to explore changes associated with mechanical strain and temperature. Although no vibrational modes associated with cross-linking of the fibers could be identified, the secondary structure of dehydrated fibrous elastin was significantly different from alpha-elastin. The former differed from previous experimental measurements, but was close to the theoretical predictions with 36% beta-structures, 46% unordered, and 18% alpha-helix. Alpha-elastin contained 29% beta-structures, 53% unordered, and 18% alpha-helix. In nuchal fibers the amide I mode was polarized, consistent with the peptide bond. Strains of up to 60% in ligament fiber bundles resulted in no significant shifts in peak position or in secondary structure. Polarization measurements revealed that the peptide bonds and several side chains re-orientated closer to the fiber axis. Heating nuchal fibers to 60 degrees C to increase the energetic component of the elasticity was associated with a 30% increase in the proportion of beta-structures in the amide I band, a 50% increase in the amide III band, and a 50% reduction in the signal from bound water.

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confidence: 79%

The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy

2008

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“…For unstrained wool fibres, the maximum of amide I band was found at 1652 cm -1 (typical for α helical proteins) and shifted to 1672 cm -1 ( -pleated sheet conformation) in the spectrum for stretched fibres. An intensity of peak observed at 1239 cm -1 (amide III, -pleated sheet structure) increases during stretching, which confirms information obtained from amide I band analysis (Church et al, 1998). The -transition caused by stretching silk fibres was also reported (Colomban et al, 2008).…”

Section: Stress/strain Measurements In Soft Matters By Raman Spectrossupporting

confidence: 81%

“…The application of stress leads to changes in interatomic distances and consequently shifts the positions of the bands. Such effects have been observed in silk, wool and collagen fibre analysis (Church et al, 1998;Colomban et al, 2008;Sirichaisit et al, 2000;Wang et al, 2000). For unstrained wool fibres, the maximum of amide I band was found at 1652 cm -1 (typical for α helical proteins) and shifted to 1672 cm -1 ( -pleated sheet conformation) in the spectrum for stretched fibres.…”

Section: Stress/strain Measurements In Soft Matters By Raman Spectrosmentioning

confidence: 54%

Specific Applications of Vibrational Spectroscopy in Biomedical Engineering

Olsztyńska-Janus¹,

Gąsior-Głogowska²,

Szymborska-Małek³

et al. 2011

Biomedical Engineering, Trends, Research and Technologies

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“…Several well-established techniques have been used to analyze the structure transformation of wool fibers, including X-ray diffraction, [3][4][5][6] infrared spectroscopy, 7,8 Raman spectroscopy, 9,10 and differential scanning calorimetry. 11 This evidence strongly supports the view that stretching results in the structure transformation of wool fibers from an a-keratin crystalline structure to a predominantly b-keratin crystalline structure.…”

Section: Introductionmentioning

confidence: 99%

Study of the structure transformation of wool fibers with Raman spectroscopy

Liu

2006

J of Applied Polymer Sci

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Raman spectroscopy and tensile tests were used to investigate the structure transformation of stretched wool fibers with stretching ratios up to 110%. The typical bands analyzed in this article included the amide I region, the amide III region, the CÀ ÀC skeletal vibration region, and the SÀ ÀS and CÀ ÀS bond vibration region. To investigate the variations of the crystallinity and orientation of the wool fibers, the density and birefringence of the fibers were also measured. The results showed that the secondary structure of the wool fibers was transformed from an a-helical structure to a b-pleated-sheet structure during the early stage of stretching. When the fiber was stretched more than 80%, the mechanism of stretching mainly relied on the slippage of the peptides. Meanwhile, the pretreatment of the wool fibers with sodium bisulfite and the setting processing resulted in the reduction of the concentration of the SÀ ÀS bonds. The results for the density and birefringence showed that the degree of crystallinity of the wool fibers decreased, whereas the degree of orientation increased during the stretching. The tensile behavior of the stretched wool also supported the a?b microstructure transformation. The diameter results showed that the extent of slenderization was about 25.3% when the stretching ratio was 80%.

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The effects of stretching on wool fibres as monitored by FT-Raman spectroscopy

Cited by 39 publications

References 8 publications

The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy

The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy

Specific Applications of Vibrational Spectroscopy in Biomedical Engineering

Study of the structure transformation of wool fibers with Raman spectroscopy

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