Synthesis Of Waterborne Emulsifier Veova/F Emulsion With Core/Shell Structure And PVDC Latex & High Barrier Mechanism Of Coatings By EIS And Evaluation Of Coatings

Waterborne coating technology is the trend of the world coating industry of the future,synthesis of high performance waterborne resin is the base of the advanced water-based coatings.In this work,high performance waterborne emulsifier Veova/F emulsion with core/shell structure was synthesized.PVDC latex was synthesized, and the barrier mechanism of waterborne PVDC emulsion to oxygen and water vapour was researched, the influences of the surfactant's amount, the initiator's amount, the temperature and the concentration of vinylidene chloride (VDC)on the oxygen transmissivity rate (OTR) and water vapour transmissivity rate (WVTR)were discussed.The deterioration process of polyurethane coatings has been simulated,a rapid method for evaluating coatings was got by using the frequency of the maximum phase angle of EIS.The main contents were listed below:1. Synthesis of waterborne emulsifier Veova/F emulsion with core/shell structureAMPS(2-Acrylamido-2-methyl-1-propanesulfonic acid)was used as emulsifier, Hexafluorobutyl acrylate (HFBA) and Veova-9 were used as modified monomer. Synthesis of waterborne emulsifier Veova/F emulsion with core/shell structure by core-shell technology and semi-continous'hunger state'dropping method.Its chemical structure was verified by IR. Emulsion particle structure was characterized by transmission electron microscopy. Particle size distribution was tested. Surface chemical elements and content were characterized by XPS. Contact angle and water resistance coating has been tested. The results showed that: emulsion membrane of Veova/F has superior water resistance, emulsifier free emulsion polymerization method can fundamentally solve the problem of water resistance of waterborne resin. The core-shell technology can provide the best performance price ratio.2. Synthesis of waterborne PVDC latex and the research on the barrier mechanism of waterborne PVDC emulsion to oxygen and water vapourThe vinylidene chloride (VDC) and the methacrylate (MA) were used as the main monomer, the influences of the surfactant's amount, the initiator's amount, the temperature and the concentration of vinylidene chloride (VDC)on the oxygen transmissivity rate (OTR) and water vapour transmissivity rate (WVTR)were discussed to get the best barrier performance PVDC latex.The electrochemical behavior of the coating was studied by EIS(Electrochemical Impedance Spectrum),the barrier mechanism of PVDC emulsion to oxygen and water vapour were discussed. Its application in water-based anticorrosion coating was demostrated.3. EIS analysis of coating and rapid evaluation of performance of coatingThe corrosion process of polyurethane coatings has been simulated using MS model by computer calculation.The mechanism of polyurethane film barrier was first proposed and studied by EIS. The results show that: the corrosion resistance of polyurethane coating modified by fluorine-containing siloxane or siloxane were much better than the ordinary polyurethane coating. Using the initial circuit model immersion coating, the frequency at the maximum phase angle was mesured in the coating EIS Bode diagram of early immersion. In accordance with the linear relationship of frequency at the maximum phase angle and the coating resistance (Rc),we can evaluate the perfomance of coating rapidly without accurate assessment EIS data.