Characterization of Surface Modified Carbon Fibers and Their Epoxy Composites by Small Angle X-Ray Scattering

摘要

This paper correlated the interlaminar shear strength of 7 different carbon fiber/epoxy composites with structural characteristics determined by Small Angle X-ray Scattering (SAXS) measurements. The carbon fibers were all of the same type but had different surface treatments. The SAXS patterns of the fibers and of the composites showed a highly nonlinear Guinier region which could not be approximated by traditional linear regression. A new approach to the Guinier approximation was developed to treat this nonlinear curve using a polynomial of second order. The radius of gyration (RG) of the fibers, as determined by this new method, correlated clearly with both the extent of the surface treatment and the interlaminar shear strength of the composite. Also the difference in scattering between a dry fiber and a glycerine soaked fiber provides a way to characterize the changes obtained by surface treatments. These methods provide new ways to estimate the efficiency of a surface treatment and its effect on the interlaminar shear strength by analyzing the SAXS patterns of the fibers. (ERA citation 12:031151)