Commingled hybrid yarn diameter ratio in continuous fiber-reinforced thermoplastic composites

Manufacturing of lightweight structures from fiber-reinforced thermoplastic composites is of great benefit. Among various manufacturing methods the usage of semi-finished products is in high demand. To improve the mechanical properties and increase the productivity, the commingled hybrid yarn was developed recently. Among many parameters the fiber volume fraction and was diameters of reinforcement filaments and thermoplastic filaments in hybrid yarn are investigated in this study. The target is to improve the impregnation of reinforcement by molten thermoplastic polymer. Two hybrid yarn samples are illustrated (a) high performance thermoplastic PEEK/CF and (b) standard thermoplastic/glass fibers polypropylene (PP)/GF. The unidirectional (UD) composite samples, manufactured using thinner filaments, show little improvement of mechanical properties within the investigated region. In this study, a new technological approach will be introduced to increase the homogeneity of PP/GF commingled yarns by online hybrid spinning.