Evaluation of the Mechanical Properties of Braid-CFRTP Produced by Pultrusion

Abstract

Braids, which have been used to make hoses and pipes, are getting a lot of attention in the field of fiber reinforced plastics (FRP) due to its high reinforcing effect of continuous fibers. For braided composites, pultrusion, known as braid-pultrusion (BP), is often applied, and mainly thermosetting resins have been used for matrix resin. Considering recyclability and productivity, thermoplastic resins are better to be used for matrix. Nevertheless, the thermoplastic resin has the disadvantage of high viscosity, making it difficult to impregnate into the fiber bundle. The unimpregnated area becomes the starting point of fracture, so it is necessary to develop a method to improve the impregnation property. In this study, to improve the impregnation property of the braided composite in BP using a thermoplastic resin, a new pre-impregnation method of resin was developed using a solution in which PA6 was dissolved in HFIP. For comparison, three types of specimens were prepared: two types of specimens were obtained by pultruding the braids once or twice through the die without pre-impregnation, while the third type was pre-impregnated rods pultruded once using the same die. The molded product pre-impregnated with the HFIP solution of PA6 showed the lowest porosity and the highest impregnation ratio, resulting in the highest tensile strength.