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Study of the structure transformation of wool fibers with Raman spectroscopy
Author(s) -
Liu Hongling,
Yu Weidong
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.23862
Subject(s) - crystallinity , materials science , wool , composite material , raman spectroscopy , ultimate tensile strength , fiber , slippage , birefringence , polyamide , microstructure , optics , physics
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 CC skeletal vibration region, and the SS and CS 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 α‐helical structure to a β‐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 SS 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 α→β microstructure transformation. The diameter results showed that the extent of slenderization was about 25.3% when the stretching ratio was 80%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1–7, 2007