Investigation of the formation and structure of black and law lacquer films by neutron and X-ray scattering

Nankawa, Takuya

no journal, , 

Urushi, the main component of which is urushiol, is a natural lacquer polymer which has unique characteristics, including high water resistance, chemical resistance, and antibacterial propertiesl. Since ancient times, lacquer has often been used not only in its original brown color, but also in shades such as black and vermilion. Black lacquer is traditionally produced by adding iron to lacquer, but the reaction mechanism both raw and black lacquer (Kiurushi and Kurourushi, respectively) is largely unknown even today. In this study, we investigated the structure of them in order to develop a new coating material that has high durability and antibacterial properties by mimicking urushi coating using various measurement methods (FT-IR, XANES, EXAFS, SAXS, SANS). As a result, the addition of iron ions is thought to catalyze the polymerization and blackening of urushiol using iron as a catalyst, as well as the arrangement of the iron core to form the structure of the lacquer. This is the first observation that the polymer network structure is completely different between raw lacquer and black lacquer, and the structural changes of black lacquer during UV irradiation and heating were also investigated in the same way. It was indicated that the physical properties of the lacquer film could be controlled by controlling the formation reaction of the lacquer film.