handbook of carbon, graphite, diamond and fullerenes

206 Carbon, Graphite, Diamond, and Fullerenes
of polymer matrix, the processing variables (i.e., temperature, post-cure,
etc.), the ratio of fiber to matrix, the type and properties of the carbon fiber,
the orientation of the fibers, and the fiber architecture in general.
A comprehensive study of the effect of all these variables on the
properties of the composite is a formidable task which has yet to be
undertaken. Yet a good deal of information is already available, part of
which is summarized in the following three tables. The data are compiled
from the literature and suppliers' bulletins. Table 9.3 lists the effect of the
type of carbon fiber.
Table 9.3. Effect of the Type of Carbon Fiber on the Properties
of Carbon-Epoxy Composites^ 14 '
Density, g/cm 3
Tensile strength, MPa
Modulus, GPa
Compressive strength, MPa
Shear strength, MPa
Thermal conductivity, W/m-K
T650/42*
1.6
2585
172
1723
124
8.65
Type of Fiber
P55**
1.7
896
220
510
55
74
P120***
1.8
1206
517
268
27
398
* T650/42: a high-strength, intermediate-modulus, PAN-based fiber
** P55: an intermediate-modulus, pitch-based fiber
r P120: a high-modulus, pitch based fiber
Notes: 1. The fibers are produced by Amoco Performance Products Inc.
2. The composites have the same epoxy matrix with 62 vol.% fiber.
3. Fiber orientation is unidirectional (0°) and tested in the fiber direction.
Particularly noticeable is the high thermal conductivity of the graphitized
pitch-based fiber composite which is 46 times that of the PAN-based
material.
Table 9.4 shows the effect of fiber orientation on the properties. The
large differences in tensile strength and modulus of unidirectional laminates
tested at 0 and 90° should be noted.