Investigation of fiber content evaluation methods of carbon fiber reinforced thermoplastic composites

Thermoplastic-based composites are becoming the preferred material for structural and non-structural components in the composite production industries. One of the most critical elements determining the characteristics and performance of fiber-reinforced composites is the fiber content. The fiber volume fraction (Vf) of carbon/polyamide410 (C-PA410) composite is evaluated using standard acid digestion, the unique two-stage thermogravimetry (TGA) method and 2D image processing method, with Vf values of 24.0%, 23.1%, and 18.3%, respectively. For statistical purposes, a substantial number of samples from each composite batch were tested and analyzed. The two-stage TGA approach used in this study, involves measuring the constituent content of carbon fiber thermoplastic composites in nitrogen first and subsequently in air. The standard acid digestion and the two-stage TGA method used in this study provided comparable results. The 2D image processing method, on the other hand, yields a lower volume fraction of fiber. The two-stage TGA approach has been proven to be more convenient in terms of accuracy, safety, and speed. This technique has been validated by testing a control specimen of a material (Toray Cetex (R) TC910 PA6) with a known weight fraction.