Hot-compacted self reinforced polyamide 6 composite laminates

Polyamide 6 (PA6) based sheets are produced by a typical hot compaction procedure and characterized in terms of thermal properties, mechanical behavior and morphological features. Starting from two commercial clothes mainly constituted by woven PA6 fibers, single polymer composites (SPCs) involving 24, 30 and 36 layers of each fabric were prepared and investigated taking compression molded plates based on a commercial neat PA6 grade as the reference material. All materials were prepared under similar processing conditions in terms of pressure profile and duration of the various stages of compaction but using a higher consolidation temperature for the neat PA6 with respect to composite laminated systems. The improvement of both static and dynamic flexural moduli and the simultaneous reduction of the Charpy impact parameters, by increasing of the reinforcement effect, confirmed the typical need to balance stiffness and toughness performances, well established for conventional composite systems, unless optimized production process and/or hybridization approaches are considered. In fact, a good compromise of mechanical performances was detected for the thickest SPC laminates based on a hybrid PA6/polyurethane fabric and ascribed to the occurrence of more efficient failure mechanisms rather than the simple fiber breakage as witnessed by morphological analyses.