Research Of Supercritical CO₂ Spray Technology For Alkyd Varnish And Preparation Of Nanometer Composite Coating

Environmental pollution has become the problem needed to be solved urgently, atmosphere pollution puzzled people even more. Moreover Traditional solvent based coating needs a lot of quick volatile organic solvent which was volatilized into the atmosphere as spraying,so it pollutes environment badly.Entrusted by Fujian Donghai Coating Company we investigate feasibility that supercritical CO₂ (SC-CO₂) spraying of alkyd coating and exploit composite nano-TiO₂-based light self-cleaning coating. The former can reduce the release of organic solvent in the course of coating spraying and spraying cost, and improve quality of coating spraying; the latter can take the coating film of light self-cleaning coating as the fixed phase of nano-TiO₂-based photocatalyst, which make the film of coating not only have decoration and material protection effect but also have Photocatalytic self-cleaning and atmosphere purification functionThe application of supercritical CO₂ and the research headway are directly correlative with our study was summed up ,the advantage of coating spraying technique which quick volatile solvent is replaced by supercritical CO₂ was summarized , also summed up development of composite nanoparticles coating, and summarized the study of composite nano-TiO₂-based light self-cleaning coating.The influence of supercritical CO₂ on the alkyd coating was characterized with FT-IR spectrum and viscosity average molecular weights. The experimental results indicated that supercritical CO₂ would swell alkyd coating and character of coating film substance did not change basically. So it showed supercritical CO₂ spraying did not change the quality of coating film. The partial mole volume of xylene in supercritical CO₂ was also measured,the experimental results indicated that it was minus which could heighten the swell capability of supercritical CO₂ in polymer. So in order to reduce production cost, 5% remaining xylene in alkyd coating in the production did not remove in the course of supercritical CO₂ spraying. The mimic ternary phase behavior of CO₂ - alkyd resin-200# gasoline was studied which could be based on technological conditions of spraying selection. The influence of nozzle's...