The research involves using phenol-formaldehyde (novolak) resin as a
matrix for making composite material, while glass fiber type (E) and asbestos fiber
type chrysolite were used as reinforcing materials. The specimens of composite
materials were prepared from each type of all the fibers mentioned above with
weight fraction of (60%) of their weight. After that the hybrid composite material
was made by the addition of different types of these fibers in the same weight
fraction, these specimens were made in different ratios of hexamethylenetetramine
content including (10%) and (14%). Then the study on some thermal properties
was carried out on all composites which were prepared and the results were
compared with those of novolak resin alone. The effect of reinforcement with
fibers on the properties of resin was studied, too. Thermal properties were studied
including heat distortion temperature (HDT), thermal gravimetric analysis (TGA),
erosion resistance by use of oxyacetylene burner and thermal conductivity. In
general, the results have shown that after the reinforcement with different
fibers and types of improvement factors improve the thermal properties. The
positive effect of increasing the hexamethylenetetramine is to increase most
properties of resin and its composites have shown a new case, which combines
between the other reinforcement cases i.e. the possibility of combining properties
in one material in a balanced form.