Improvement And Study Of A New Waterborne Epoxy Coating With Room Temperature Curing

In this paper, polyethylene glycol (PEG) and diphenylmethane diisocyanate (MDI) was introduced into the epoxy resins by modification, and a kind of waterborne epoxy emulsion was prepared. The emulsion was processed with vertical colloid mill and ultra-high pressure homogenizer. An atable emulsion is prepared, with particle size of 200-300nm. Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectrometer (HNMR) and Gel permeation chromatography (GPC) were used to analyze intermediate and final products and deduced the reaction mechanism and the structure of products.Secondly, a new curing agent with room temperature curing was perpared with diethylenetriamine modified by epoxy resins. Amount of glacial acetic acid used and influence of PEG prepolymer were studied, to make sure the experiments. The curing agent prepared was soluble and compatible with epoxy resins, which was easily to disperse in the epoxy emulsion, and curing rate is moderate. FTIR and HNMR were used to deduce the reaction mechanism and the structure of products.Thirdly, a coating was prepared with the emulsion and the curing agents. The film was transparent and glossy. FTIR was used to deduce the reaction and film formation mechanism, X-ray diffraction (XRD) was used to analyze the internal structure of the film, which showed that structure of the film is a kind of"semi-crystalloid". Scanning electron microscopy (SEM) was used to investigate the apparent morphology of the film. Moreover, thermal analysis was carried out by Ifferential scanning calorimeter (DSC), Dynamic mechanical thermal analyzer (DMA) and Thermal gravimetric analysis (TG), which showed Tg of the film was 43.5℃, minimum tanδof the film was 0.467, and decomposition temperature was 300℃.Lastly, a anticorrosion coating was prepared of the emulsion and the curing agent, by adding titanium dioxide, carbon black, talc powder, and water-based additives. Performance of the coating was tested, which the mechanical properties and corrosion resistance were excellent.