Prediction of mechanical properties of short kevlar fiber‐nylon‐6,6 composites

Injection molded short Kevlar (DuPont) fiber/nylon‐6,6 composites have been studied. Fiber length and length distribution were measured as a function of processing variables. Critical fiber length was measured by an embedded single‐fiber method. Tensile modulus of the molded composites was predicted by an adapted classical lamination analogy. Fiber and matrix orientation factors, derived from X‐ray diffraction, were introduced to modify Kelly Tyson equation to estimate the composite tensile strength. It has been found that fiber length is dramatically shortened by the injection molding process, and is affected by processing conditions. Predictions gave reasonable agreement with data for tensile modulus and strength.