Tensile strength, compression strength, bending strength, and fracture toughness of phenol
formaldehyde type novolac resin (PFN) reinforced with randomly-oriented different fibers as
well as powders in terms of mechanical properties, which are subject to change in different
additives volume fraction have been studied. Tensile strength, σT , results show that σT
increases with the increasing volume fraction of additives. Failures display two mechanisms
according to the kind of additives. Where, it can be observed, pullout mechanism with respect
to fibers composites, and rupture mechanism with respect to powder fillers composites.
Compression strength, σc , results show that σc increases with the increasing volume fraction
of additives. Bending strength, σf, results show, that σf increases progressively by succession
of volume fraction of fibers. Fracture toughness Gc , results show that Gc increased with
increasing of volume fraction of additives. Failure takes place through two mechanisms,
according to additives kind. Where, the failure takes place by pullout mechanism with respect
to fibers composites, and by pining mechanism with respect to powder fillers composites.