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.

Carbon fiber/nylon 6 powder coated and commingled tows were braided into biaxial braids with a ±45° braid angle. Consolidation experiments were carried out to study the influence of consolidation conditions on the properties of the laminates using a 23 full factorial experimental design. The consolidation studies reveal that commingled tows require more severe consolidation conditions than powder coated tows to obtain comparable properties. The dependence of powder‐coated laminate qualities like void content and fiber volume fraction on the consolidation conditions is reported. The ±45° braided laminates are tested for tensile properties. Although the dominant mode of failure of the laminates is shear failure between the fibers and the resin, the failure is non‐brittle because of fiber interlacement in the braided preforms.

Powder coated tows have a structure that is significantly different from conventional textile fibrous strands. The properties of carbon fiber tows coated with nylon 6 powder have been characterized in Part I of this series of Papers. In this study, braiding experiments have been carried out with powder coated and commingled tows. An approach has been established to estimate the damage inflicted to the towpregs during the braiding operation using a braiding simulator. Braiding studies reveal that the towpreg properties of flexibility and friction coefficient have significant effects on the braidability of these towpregs. These towpreg properties also have similar effects on the towpreg damage assessed with the braiding simulator. Commingled tow is easier to braid than powder coated tow. Wrapping facilitates braiding both types of tows.

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