Printability and mechanical behaviors of continuous polyamide fiber reinforced polycaprolactone composites

Abstract Polycaprolactone (PCL) is a biodegradable material that has received significant attention in the last decade. It is characterized by low toxicity and biocompatibility, making it a common choice as a tissue scaffold material in the medical field. However, its low mechanical performance has limited its application. This work focuses on the development and characterization of a PCL based printing material reinforced with continuous polyamide 6 fiber (PA6/PCL). PA6/PCL filaments were produced through a hot melt impregnation process. A custom fused deposition modeling (FDM) printer was used to print the PA6/PCL composites. Thermal analysis was conducted to assess the thermal properties of the composite materials. Mechanical tests were performed to evaluate the mechanical properties of the printed composites and determine the effect of PA6 continuous fiber on their mechanical properties. The study showed that adding continuous PA6 fibers significantly improved the strength and modulus of PCL. When 7.9 wt% PA6 fiber is added, the tensile strength of PCL printed parts increased by more than 300%, and the tensile modulus increased by 36%. In addition, flexure strength increased by 130% and flexure modulus by 150%. Scanning electron microscope was used to study the fracture surfaces of the composites and it was found that the main failure modes were fiber fracture and debonding between fiber and matrix. This research demonstrates that adding continuous PA6 fibers tremendously enhances the mechanical properties of printed PCL parts. This novel composite material can potentially broaden the applications of FDM technology and provide more material options for biomedical applications. Highlight A novel FDM composite material with excellent tensile strength was developed. Continuous PA6 fiber has been used to reinforce PCL. A new test method was developed for evaluating filament material for FDM. The tensile strength of PCL is improved by 300% when 7.9 wt% PA6 fiber is added. The printability of the FDM composite material has been confirmed.