Manufacturing of Thermoplastic Composite Rods using Vacuum Assisted Pultrusion

Abstract

Pultrusion is an automated composite manufacturing process allowing the continuous production of constant cross-section beams. Pultrusion has been successfully used in the industry with thermoset matrixes. The pultrusion of thermoplastic matrix composites, however, has not reached the same level of industrial penetration. This can be attributed to the viscous thermoplastic polymer melts. Their high viscosity hinders the impregnation flow of the reinforcing fibers, resulting in porous composites. The aim of this study was to reduce the porosity of pultruded composites. The addition of a vacuum chamber was used to extract entrapped air in the composite during pultrusion. The pultrusion system is also equipped with 31 thermocouples, 2 load cells and a rotary encoder to acquire processing parameters. Different material systems were used: Carbon fibers with Nylon polymer as well as bio-sourced flax fibers and PLA polymer. The reinforcement and polymer, procured as filaments, were first combined in hybrid yarns. Pultrusion experiments were done at 50 mm/min with or without vacuum. Pultruded rods’ consolidation quality was assessed by microscopy. It was observed that the addition of the vacuum chamber can reduce the porosity. These results are promising features that may allow the largescale production thermoplastic composite pultruded parts.