Tensile Properties of Glass Fiber Knitted Fabric Reinforced Polypropylene Composite Made from GF/PP Commingled Yarn Affected by Prestretching

Abstract

The effects of prestretching of rib 1: 1 knitted fabric preform on the tensile properties of GF/PP composites are investigated in this study. The preform is made from GF/PP commingled yarn. As far as tensile stiffness and tensile strength are concerned, there is a critical value of prestretch ratio. An increase in the prestretch ratio within the range of this critical value increases both the tensile stiffness and the tensile strength. If the prestretch ratio goes beyond this critical value and continues to increase, both tensile stiffness and tensile strength display a tendency of slight decrease because of the break of more glass fibers. The failure strain of the composites decreases with the increase of the prestretch ratio because of the decrease of the stretchability of the knitted reinforcements.