Reprocessing of fiberglass reinforced polyamide 66: Influence on short term properties

The fiber length distribution was found to control the overall short term performance of reprocessed heat‐stabilized short fiberglass reinforced polyamide 66. Length changes, and matrix and interface degradation were studied. Fiber shortening dominates during compounding and during the first injection molding cycle. Further regrinding and remolding has a lesser effect. The short term mechanical strength decreased for reprocessed samples. Using a modified Kelly‐Tyson model, the lower tensile strength of reprocessed samples, compared with virgin samples, can be explained by fiber shortening. Reprocessing had a negligible effect on the strength for both the fiber matrix interface and the matrix of this system. Studies on unreinforced samples confirmed that thermal degradation of the matrix during reprocessing had a negligible effect on short term mechanical performance.