Relationship between crystalline structure of polyamide 6 within carbon fibers and their mechanical properties studied using Micro-Raman spectroscopy

We aim to determine the relationship between the local crystalline structure of polyamide 6 (PA6) within carbon fibers (CFs) and the mechanical properties of unidirectional CF-reinforced PA6 composites. Two types of CFs with different surface profiles (one smooth and one rough), used as reinforcements, were employed for the transverse Charpy impact test of unidirectional PA6/CF composites. The surface profile of CF influenced the impact strength and debonding appearance. The crystalline structure of PA6 within CFs was investigated using micro-Raman spectroscopy with a spatial resolution of 1 ?m. Based on the Raman study, it was suggested that the impact strength and debonding appearance were attributed to the varying polymorphism (?-phase, mesomorphic ?-phase, and ?-phase crystal) of the PA6 matrix between the interface and locations away from the interface (i.e., the bulk region), depending on the surface profiles of CF.

Automated summary

The research found that the surface profile of carbon fibers has a significant impact on the impact strength and debonding appearance of polyamide 6 composites. Micro-Raman spectroscopy analysis revealed that the polymorphism of the PA6 matrix varied between the interface and bulk region, depending on the surface profiles of the carbon fibers.