Experimental and numerical analysis of a new thermoplastic pultrusion technology of CF/PA6 rod using prepreg tapes

Abstract Fiber‐reinforced thermoplastic polymer composites, as replacements for steel reinforcements, are anticipated to enhance service performance and lifespan due to their reprocessability, recyclability, high toughness, and durability. In this study, a thermoplastic pultrusion technology was developed using prepreg tapes. With this technology, carbon fiber‐reinforced polyamide 6 (CF/PA6) rods with a diameter of 6 mm were prepared successfully using CF/PA 6 prepreg tapes at three pulling speeds of 0.2, 0.5, and 0.8 m/min. The temperature field, dynamic viscosity, microscopic morphology and mechanical properties of CF/PA6 rods were tested and analyzed to study the effect of pulling speed on the surface finish quality and consolidation. The results showed that the simulated temperature field within the CF/PA6 composites well matched the practical temperature field, attributed to the application of the dynamic mesh technique. An optical surface finish quality (Sa = 0.46 μm) was achieved at a pulling speed of 0.2 m/min, due to the increased dynamic viscosity of the PA6 resin, which enhanced shear stress between the composite and the cooling die cavity. Additionally, the lowest void content (0.7%) was achieved at this pulling speed. Possible reason was the fact that the increased pulling speed decreased the heating time of CF/PA6 composites, resulting in the presence of unconsolidated tapes in the inner region. The flexural strength, flexural modulus and interlaminar shear strength of CF/PA6 rods prepared at 0.5 and 0.8 m/min decreased by 20.7%, 5.8%, and 6.6%, as well as 28.6%, 15.2%, and 23.1%, respectively. Highlights A thermoplastic pultrusion technology was proposed by using prepreg tapes. The temperature field was accurately predicted using dynamic mesh technique. The dynamic viscosity was a major factor affecting the surface quality. Deconsolidation of the prepreg tapes caused an increase in void content.