Empirical relations of the mechanical properties of polyamide 6 reinforced with short glass fibers

The dependence of the mechanical properties on the length of reinforcing fibers in hydrolytic polyamide 6 (PA 6) Matrix was studied. The fibers create a polydisperse system and the fiber distribution can be expressed by the Tung distribution function. Modulus, tensile strength, and also impact strength measured on test pieces seem to be a linear function of the part of fiber length population (percentile) representing the reinforcing fibers longer than 200 μm (value P²). These were determined not only on test pieces but also in starting pellets. The mutual relations between the individual mechanical properties seem to be linear as well. Consequently, the mechanical properties of these PA 6 composites can be estimated from the known distribution of fiber lengths in pellets and from the P²⁰⁰values, without preparing and testing the test pieces. The fiber length distribution in pellets of the composite can be estimated from the values of mechanical data (modulus, strength, impact strength) measured on test pieces.