Effect of pull-winding process in thermoplastic composite rod on the impregnation of glass fiber

In the pultrusion process, continuous fibers reinforcement in roving forms are drawn through a pultrusion die. Therefore, the fibers reinforcement in the final product are generally oriented in the longitudinal axis. In this research, for manufacturing of composite rods, on the basis of previous studies and researches, the E-glass fiber-polyethylene prepregs were produced firstly. Then due to the Design of Experiments (DOE), the pultruded rods with unidirectional and helically-wound layers were produced by using the prepregs. In this study, mechanism of the pull-winding process is created as a secondary process during the main process to improve the mechanical and physical properties in the other directions. One of the most important issues in the thermoplastics pultrusions is the fibers impregnation quality with the polymer base. The fiber volume fractions of the productions are found by the burn tests. The density of the specimens is found by the liquid displacement method. The microscopic images were taken from cross-section of the pultruded rods to investigate the fiber impregnation and the void distribution. Due to the surveys conducted, the fiber volume fractions in the pultruded rods was increased, using the pull-winding technique, and also the void content of these rods was decreased.