FTIR and thermal analysis of cashmere and other animal fibres

In this paper, sereval varieties of animal fibres including cashmere and Australian fine Merino wool have been analysed by Fourier transform infrared microscope and differential scanning calorimeter. The results showed that both Chinese and Australian cashmere fibres started absorbing heat at a relatively higher temperature but were thermally degraded quicker than other animal fibres tested. However, the mass changes (within the temperature range of 200oC to 350oC) and associated onset temperatures varied among fibre varieties. From the attenuated total reflectance spectra, the Chinese cashmere was clearly different from Australian cashmere and wool in a peak near 1040 cm-1 wavelength for S-O stretching of cysteic acid residues. The Chinese cashmere presented a stronger absorption at 1019 cm-1 wavelength, while Australian cashmere and wool peaked at 1079 cm-1 wavelength and had a weaker absorption. Combined with thermal analysis, the normalised R-SO3 - content of cysteic acid residues to the amide II peak of the protein backbone may have potential use in identifying Australian fine Merino wool from Chinese cashmere.