屋外暴露により劣化した塗膜の表面分析

An urushi film was prepared through nayashi and kurome processes. The film was exposed to direct daylight. The surface of the film was analysed by X-ray photoelectron spectroscoy (ESCA), infrared absorption apectroscopy (IR), scanning electron microscopy (SEM) and elemental analysis. RC-O-CR' group and oxygen content on the surface increased considerably with exposure time. On the contrary RC-H and RC-O-H groups decreased. These changes occurred only on the film surface. Pinholes and cracks which would lead to brittleness of the film were observed on the surface.