Influence of fibre content, moisture content, and anisotropy on the mechanical properties of direct compounded compression moulded carbon/PA66 and glass/PA6 composites

Long fibre thermoplastic (LFT) materials are employed in a diverse group of engineering applications, and this usage makes it critical to understand how various loading and environmental settings affect the mechanical properties of LFT materials. In this study, the tensile properties of direct-compounded, compression-moulded glass/PA6 with 30% and 45% fibre content and carbon fibre-reinforced thermoplastic (LFT-D) materials were investigated, along with shear properties for glass fibre-reinforced LFTs. Additionally, the tensile and shear properties of glass/PA6 in four different material directions of 0°, 45°, −45°, and 90° were also examined. The results of this study revealed that carbon/PA66(40%) exhibited 67% and 45% higher tensile strength compared to glass/PA6(30%) and glass/PA6(45%), respectively. The behaviour of the glass/PA6 material shifted from brittle to ductile under tension and shear loads when exposed to moisture, regardless of the percentage of fibre content. Notably, the tensile toughness of the glass/PA6 material exhibited a significant increase of up to 230% in specific material configurations from dried to undried samples. The findings of this study will assist in the selection of the optimal LFT material for use in desired loading and environmental conditions and can serve as input for the numerical modelling of these composite materials.