Page 308 - Engineered Interfaces in Fiber Reinforced Composites

I
Chapter 7. Improvement of transverse fracture toughness with interface control 289

WALcoated -
Prediction
0 Uncoated ---

--

-80 -40 0 40 80
(a) TEMPERATURE (C)

0
-80 -40 0 40 80
(b) TEMPERATURE CC)
Fig. 7.6. (a) Transverse impact fracture toughness and (b) interface debond length versus testing
temperature for carbon fiber-epoxy matrix composites with and without PVAL coatings on fibers. After
Kim and Mai (1991b).

Table 1.2
Mechanical properties of carbon fiber-epoxy matrix and Kevlar fiber-epoxy matrix composites with and
without PVAL coating at room temperaturea.

Fibers Transverse fracture Flexural strength Interlaminar shear Interlaminar
toughness (kJ/m2) (MPa) strength (MPa) fracture toughness
(kJ/m2)
Carbon fiber
Uncoated 50.3 683 58.9 0.428
PVAL coated 98.7 758 50.5 0.43 1
Kevlar fiber
Uncoated 139 518 42.6 -
PVAL coated 187 522 25.4 -
'After Kim and Mai (1991b).