Carbon Fibers/Polyamide 6 Composites Based on Hybrid Yarns

Abstract

This paper reports the results of the analysis of carbon fiber/ polyamide 6 (C/PA6) composites on micro-and macroscale. Two different hybrid yarns, side-by-side (SBS) and fiber-impregnated (FIT) yarns have been studied. To provide information about the role of the surface sizing on the overall properties of the composites, differently sized carbon fibers (C-Hercules and C-Torayca) are used for preparation of model and macrocomposites based on SBS yarns. Consolidation of macrocomposites is performed based on previously optimized processing parameters (2508C, 3 MPa, 30 min) obtained by DSC measurements of model composites. The properties of the composites are studied by tensile test, DMTA, DSC, and TGA. The homogeneity of the fiber distribution and surface fracture after tensile test are analyzed by SEM. The comparison of the results of the same type composites with differently sized carbon fibers has shown improvement of the mechanical properties ($30%) due to the proper fiber/matrix interface (E ?CH/PA6 ¼ 66.7 MPa, E ?CT/PA6 ¼ 44.5 MPa). Thermal analysis of the model and macrocomposites has shown that the crystallization energy conditions are more suitable in composites than in the neat PA6 matrix (t i CH/PA6 ¼ 0.87 min, t i PA6 ¼ 0.92 min, T onset CH/PA6 ¼ 2068C, T onsetPA6 ¼ 2168C).