The influence of bath temperature on the properties of pultruded glass fiber reinforced rods

Pultrusion is one of the several manufacturing processes for polymer composites. It involves resin-impregnated fibers that passed through a heated die, while the resin cures to produce a solid profile in the desired shape. Many processing variables such as die temperature, pull speed, fiber impregnation, resin viscosity, among others, affect the composite quality and the process efficiency. In fact, a good understanding and careful control of all these variables are needed to avoid defective profiles as well as to achieve better processing conditions. In this paper, the relationship between the resin bath temperature and the mechanical properties of pultruded rods such as tensile strength, elastic modulus, and hardness was established. The effect of resin viscosity on the fibers wet-out, cure position inside the die and the void formation was also investigated. The results showed that the rods made at higher bath temperatures presented higher tensile strength, elongation at break and hardness, but lower modulus of elasticity. This behaviour was correlated with the void content yielded during the profile formation.