Page 133 - Handbook of Properties of Textile and Technical Fibres

Physical, chemical, and tensile properties of cashmere, mohair, alpaca 113

Investigating a range of lustre wools and mohair from different origins, Weideman
et al. (1988) reported that there was an overlap in cuticle scale height distributions be-
tween mohair and wool. Mean scale height for mohair samples ranged between 470
and 570 nm with 95% confidence limits for samples ranging between 360e600 and
390e750 nm. McGregor and Quispe (2017) found mohair had the greatest cuticle
thickness (554 nm), Peruvian vicu~ na the thinnest (247 nm) with other fibers interme-
diate: cashmere 424e430 nm; bison 394 nm; qiviut 366 nm; Australian alpaca
394 nm; Peruvian alpaca 335 nm.
Wortmann and associates developed a system of using cuticle scale height measure-
ment for the identification of animal fibers in textile garments consisting of blends of
rare animal fibers with wool and man-made fibers (IWTO-58, 1998) and for use in
identifying fraudulent blending. Given the importance of fraud in the cashmere fiber
trade and the difficulties that arise in determining fiber types amongst various agencies,
auditors, and companies, the China National Cashmere Products Engineering and
Technical Centre and the Inner Mongolian Erdos Cashmere Group have hosted five
International Cashmere Determination Technique Seminars. Chinese scientists
completed the largest analysis of cuticle scales of cashmere with a survey of raw cash-
mere from their main producing regions. This provided the measurement of the cuticle
properties of over 9000 fibers from 105 samples (Yang et al., 2005; Zhang, 2005a,
2008). Cuticle scale height averaged 0.34 mmin fibers with a mean fiber diameter
(MFD) <18.0 and 0.36 mmin fibers with an MFD 18.0 mm(Yang et al., 2005).
Cuticle scale frequency declined and the ratio of fiber diameter to cuticle scale length
increased as fiber MFD increased (Table 4.2). An official reference manual containing
photo micrographs provides data on cuticle scale frequency, height and length, fiber
surface morphology, and typical and irregular cylindrical patterns of the cuticle scales
(Zhang, 2005b).
The cuticle scale characteristics of alpaca fiber were investigated by Wildman
(1954) and Wortmann et al. (1988) (see Fig. 4.2), but they did not distinguish between
Huacaya and Suri alpaca. Suri alpaca scale frequency for fiber ranging in MFD of
24.8e28.2 mm ranged from 8.0 to 10.3 scales/100 mm(Wang et al., 2003). Valbonesi
et al. (2010) investigated cuticle scales of Suri alpaca (MFD 24.4 mm), Huacaya fiber
(MFD 27.4 mm), and Llama (chaku woolly, MFD 29.6 mm) fiber. The relationship be-
tween cuticle scale frequencies differed with MFD of both Suri and llama fiber but not
Huacaya fiber. For Huacaya, the cuticle scale frequency was 9.1/100 mm. For Suri, the
cuticle scale frequency increased from 7.5/100 mm, at an MFD of 20 mm, by 0.29 for
every 10 mm increase in MFD, and for llama it increased from about 9.2 at an MFD of
20 mm, by 0.54 for every 10 mm increase in MFD. Cuticle scale height did not differ
between samples of llama, Huacaya, and Suri fiber; they were respectively 0.40, 0.52,
and 0.47 mm. However, the percentage contribution to the total variation owing to vari-
ation among types of fleece, among specimens within each type of fleece, and among
measurements within specimens were respectively 8.3%, 39.6%, and 52.0%. This
result indicates that variation within samples from the same fleece type account for
91.6% of the variation observed in cuticle scale height.