Page 305 - Engineered Interfaces in Fiber Reinforced Composites

286 Engineered interfaces in fiber reinforced composites

I

0 1 2 3 4 5 6 7
AMOUNT OF COATING (16~~1~~1

Fig. 7.3. Normalized impact toughness of glass fiber-polyester matrix composites with different fiber
coatings: (0) silicone vacuum fluid (SVF); 0 Dow Coming 200 Fluid of viscosity IO6 cP; (A) Dow
Corning 200 Fluid of viscosity lo5 cP. After Sung et al. (1977).

Coating thickness in pm
Fig. 7.4. Fracture toughness (0) and flexural strength (0) of silicone rubber coated carbon fiber-epoxy
matrix composites as a function of coating thickness. After Hancox and Wells (1977).

by some 100% with a silicone rubber coating at the expense of approximately 60%
loss of flexural strength depending on the coating thickness (Hancox and Wells,
1977), Fig. 7.4. It should be noted that there is an optimum coating thickness which
imparts both high flexural strength and impact toughness. Other studies using
rubber coatings include silicone rubber for carbon fiber-polyester matrix (Harris
et ai., 197 1); carboxyl terminated butadiene acrylonitrile (CTBN) copolymer for
carbon fiber-epoxy matrix system (Gerard, 1988); rubber coating for glass fiber-