Braided thermoplastic composites from powder-coated towpregs. Part I: Towpreg characterization

Textile preforms offer the potential for producing low cost, complex shaped, advanced composite structures. For thermoplastic composites in particular, it is advantageous to incorporate the resin in the tow prior to textile processing since it is difficult to impregnate dry fabrics with thermoplastic melts. Incorporating resin in the tows tends to alter the properties of the tows that are critical for textile processibility. In this paper, carbon fiber tows coated with nylon powder are studied. They are characterized for flexibility and friction coefficient, which are critical for textile processibility, and for lateral compressibility, which is critical for composite moldability. These studies reveal that the powder coated tows have higher stiffness, friction coefficient, and bulk factor compared to uncoated and commingled tows. The influence of these towpreg properties on their braidability has been studied and is provided in Part II of this series.