Abstract
The relation between tensile strength and flexural strength of many compoiste materials was investigated. These included polycarbonate/glass fiber (GF), polypropylene/GF, polyamid/GF, acrylonitrile-butadiene-styrene (ABS) / GF, poly (butyleneterephthalate) (PBT) /carbon fiber (CF), and epoxy resin/GF. The relation between tensile strength and flexural strength was almost linear in the materials of injection moldings which had values over 5 (kg-cm/cm, Izot impact with V notch) of impact strength and showed good elongation (almost 1.0-3.0%). In the cases of crystalline basepolymer and materials whose adhesive condition was bad, experimental values tended to be non-linear. In addition, in the case of fiber reinforced heat cured materials which were under 2 (kg-cm/cm) of impact strength and small elongation (almost 0.2-0.5%), experimental results were far from linear. In the injection materials which had straight linear relation, tensile destruction seemed to occur on the time of flexural deformation while in the low elongation materials, strain destruction occurred.
