Page 216 - Engineered Interfaces in Fiber Reinforced Composites

198 Engineered interfaces in fiber reinforced composites

C

(b)

Fig. 5.19. Schematic presentations of (a) hydrogen bonding and (b) supramolecular structure of Kevlar 49
aramid fiber. After Dobb ct al. (1977).

Table 5.10
Properties of aramid fibers"

Property Kevlar 29 Kevlar 49 Kevlar 149
Diameter (pn) 11.7
Density (g/cm3) I .44 1.45 1.47
Tensile strength (GPa) 3620 3620 3440
Elongation at break (%) 4.0 2.8 2.0
Young's modulus (GPa) 83 135 I86
Specific strength (lo6 an) 25.5 25.5 23.9
Specific modulus (IO6 cm) 580 950 1290
Coefficient of thermal
expansion (I O-6/K)
Axial -2.26 -2.0 -1.49
Radial - 59" -

"From Morgan and Allred (1993).