Page 160 - Handbook of Properties of Textile and Technical Fibres

138 Handbook of Properties of Textile and Technical Fibres

(a) 3
PBO (σ = 3 GPa, d = 1.54)
r
Stress / GPa 1 PA-66 (σ = 1 GPa, d = 1.14–1.20)
1500 2
PBO
r
PET PET (σ r = 1 GPa, d = 1.33–1.40)
Tussah
i-PP (σ r = 0.3 GPa, d < 0.92)
1000
0
Stress / MPa Bombyx mori Nephila Density
PA66
1.5
1.0
500
madagascarensis
i-PP
Hair
0
0 10 20 30 40 50
Strain / %
(b)

HN
Glycine
CH 2
O
NH
Alanine H C CH
3
O
HN
CH Serine
2
O OH

Figure 5.1 (a) Comparison of the Nephila madagascariensis spider silk tensile behavior with
those of different synthetic fibers (PBO (poly(p-phenylene-2,6-benzobisoxazole), breaking
point not shown at 3 GPa), polyamide 66 (PA66), poly(ethylene terphthalate), isotactic
polypropylene (i-PP)), and keratin fiber (hair). (b) Schematic representation of a portion of the
silk chain indicating the polyamide backbone and the amino acid residues as side chains.
After Colomban P: Nanomechanics of advanced polymer fibers, Compos Sci Technol
69:1437e1441, 2009.

B. mori (Fig. 5.1(a)). However, the length of a fiber extracted from a silkworm cocoon
can reach 1500 m, and the spider fiber length is less than a few meters, exceptionally a
few tens of meters using special devices to extract the fiber.

5.1.2 Uses
Today silk retains its position as the finest fiber for apparel and its worldwide produc-
tion is increasing despite competition from synthetic fibers. Silk is mainly produced in
countries such as, China, Brazil, and India, where silk yarns and textiles are produced,