Gravimetric determination of carbon fibre in composites on the centigram scale

Summary A gravimetric method for determining the fibre content of carbon fibre/epoxy resin composites has been adapted for samples of about 20 to 50 mg. The epoxy resin was decomposed with sulphuric acid and hydrogen peroxide; the fibres were collected and weighed on a glass-fibre filter. Means of results from the small-scale and standard methods were not significantly different. Although developed for small samples of very thin composites, the method has possible applications in investigating the homogeneity of larger composite pieces.