Silica film coating method for veneering resin composite

Abstract

The preceramic polymer perhydropolysilazane (PHPS) is an attractive candidate as a coating material to prevent discoloration of veneering resin composites. At the present time, however, a practical method to apply this material is not available. The purpose of this study was to establish a low-temperature method for applying a silica film coating to a veneering resin composite. Two types of PHPS, NP and NL, were coated onto a veneering resin composite. The specimens were exposed to hydrogen peroxide vapor at 97˚C, and the state of the conversion process was evaluated using FT-IR. With exposure to the hydrogen peroxide vapor, a 0.5-µm-thick silica film similar to that produced by baking was formed on the surface of the NP samples in 10 min, while a 0.2-µm-thick film was formed on the NL in 15 min. The silica coating method described in this study may mitigate the discoloration of veneering resin composite.

Conversion of Solution‐Derived Perhydropolysilazane Thin Films into Silica in Basic Humid Atmosphere at Room Temperature

“…This peak was also detected in PHPS‐derived silica thin films reported by Kinashi et al . and Tanaka et al ., who prepared silica thin films by storing PHPS thin films in the ambient atmosphere and by exposing PHPS thin films to H 2 O or H 2 O 2 vapors, respectively. Although the 880 cm −1 peak could be assigned either to Si–H 34 or Si–N 31 vibrations, it should be assigned to Si–H rather than to Si–N vibration because of the following two reasons.…”

“…Since then, various techniques that convert PHPS thin films into silica thin films have been proposed. The techniques include the standing in the ambient atmosphere, the heat treatment in water vapor, the exposure to vaporized ammonia atmosphere, the reaction with water by the catalytic action of amine in the baking step, the exposure to hydrogen peroxide vapor, the hydrothermal treatment (for preparing phenylsilsesquioxane films), the ultraviolet (UV) light irradiation, the UV light irradiation under soaking in hydrogen peroxide, the O 2 plasma treatment after baking, and the O 2 plasma treatment followed by high‐pressure H 2 O vapor heating . Most of these techniques realize PHPS‐to‐silica conversion at or near room temperature, which may proceed via hydrolysis reaction .…”

Superior Properties of Silica Thin Films Prepared from Perhydropolysilazane Solutions at Room Temperature in Comparison with Conventional Alkoxide-Derived Silica Gel Films

“…2−6 The conversion of PHPS films into silica films has also been reported by Bauer et al, who exposed PHPS films in moisture-containing atmosphere in the presence of ammonia or amine as catalysts. 7 Since then, various techniques have been proposed for the conversion of PHPS films into silica films, including the standing in the ambient atmosphere, 8 the heat treatment in water vapor, 9 the exposure to vaporized ammonia atmosphere, 10 the reaction with water by the catalytic action of amine in the baking step, 11 the exposure to hydrogen peroxide vapor, 12 the hydrothermal treatment (for preparing phenylsilsesquioxane films), 13 the ultraviolet (UV) light irradiation, 14−16 the UV light irradiation under soaking in hydrogen peroxide, 17,18 and the O 2 plasma treatment followed by high-pressure H 2 O vapor heating. 19 Most of the processes are conducted near at room temperature, and involve water or its vapor, which indicates that the conversion may proceed via hydrolysis reaction.…”

Room-Temperature, Solution-Processed SiOx via Photochemistry Approach for Highly Flexible Resistive Switching Memory

“…Recently, perhydropolysilazane (PHPS), an inorganic polymer with repeat unit of [−SiH 2 –NH−], has been emerging as an ideal SiO x source for the solution process and already found applications in silicon-based semiconductor electronics. , Thanks to its unique structure, PHPS can be converted into SiO x with versatile processes, such as high temperature and exposure to ammonia vapor and H 2 O 2 solution . More recently, vacuum ultraviolet (VUV) irradiation has been successfully proved as an efficient method to prepare SiO x films from PHPS, which involves a photocleavage reaction of Si–N bonds in PHPS and subsequent oxidation reaction of the as-formed Si radicals .…”