Tensile properties of injection molded long fiber thermoplastic composites

This paper deals with the mechanical performances of a new class of injection molded long fiber composites based on PP and PBT matrices. Effects of material parameters such as fiber concentration, breakage, orientation, and matrix composition are analyzed. The critical fiber length, l ε c, of the PP long fiber composite, evaluated from the pull‐out length of the tensile fracture surface, was found to be much higher than those previously reported. Tensile strength calculated from the measured ll ε c and fiber length distribution in the molded samples was found to be in agreement with the measured values. From this work it is concluded that higher mechanical performances of the long fiber reinforced thermoplastics will be attained by the injection molding process to further reduce fiber breakage.