In Situ Small-Angle X-Ray Scattering Analysis of Phenolic Resins during Baking Process

Abstract

The inhomogeneity of molded and cured phenolic resins was investigated from the viewpoint of the higher-order structure distribution using small-angle X-ray scattering (SAXS). The SAXS intensity distribution in the 4-mm-thick molded specimen indicates the presence of higher-order structure distribution that was caused by the inhomogeneity of the degree of the curing reaction in the molding process. The change in the SAXS intensity during baking process suggests that an insufficient degree of curing reaction at the molding process causes further formation and propagation of voids with sizes ranging from tens to hundreds of nanometers. The macroscopic change in strain during baking process was also investigated