Effect of carbon type on the properties of PA6 composites

This thesis systematically investigated the effects of carbon fiber reinforcement on the mechanical properties and density of PA6 matrix composites. Our study aimed to examine the influence of carbon fiber type and ratio through density and tensile strength tests on samples. Furthermore, we sought to compare our experimental results with theoretical calculations. In composites produced by injection molding, carbon fibers with lengths of 0.08 mm and 3 mm were used as reinforcement at 10 wt% and 20 wt% ratios. Experimental results demonstrated a significant increase in both the mechanical properties and density of the composites with increasing fiber ratio. Similarly, the use of longer fibers also led to improvements in mechanical properties and density. However, a comparison of these experimentally obtained data with theoretical models revealed significant discrepancies, particularly for longer fibers. The primary reason for this difference is thought to be the discontinuous and scattered fiber arrangement resulting from the inability to fully control fiber orientation during the injection molding process. Theoretical analyses, specifically those based on the modified rule of mixtures, showed that the tensile strength of the 0.08 mm fiber structure was lower than the experimental values, while for the 3 mm fiber structures, the theoretical results were higher. Consequently, as fiber length increased, this irregular structure further amplified the inconsistency between theoretical calculations and experimental results. In conclusion, considering the effect of the production method and fiber type on the composite microstructure, increasing fiber ratio and fiber length resulted in improved mechanical properties and density. It was also observed that theoretical analyses could yield variations between minimum and maximum values.