Research On Water-based Epoxy Resin Emulsion Derived From Fumed Silica And Betonies

Epoxy resin is not water-soluble, thus in practical applications it mainly dissolves in organic solvents, which maybe bring about environmental pollution and potential security. Accordingly, waterborne emulsion using water as solvent or dispersion medium was put on the agenda and became an important environment-friendly product. At present time, adding hydrophilic emulsifiers to prepare waterborne emulsion is prevalent; but the existence of emulsifier tends to reduce the property of epoxy products as coatings, adhesives and so on. Using chemically inert particles as stabilizer to replace or partially replace the traditional emulsifiers can obtain non-surfactants emulsion. As a result of the none-use of surfactants, the difficulties on surfactants recovery and the possible adverse influences on environment can be avoided, meanwhile, the properties of products maintained, which is in line with the currently-urged environmental and economic requirements.We used fumed silica and betonies as stabilizers and emulsifiers, explored the factors influencing the type and stability of solid-stabilized epoxy emulsions, namely, category, content, wettability, observed the construction of particles at oil-water interface with micro-imaging technology and discussed the mechanism of emulsification and stabilization of solid particles. When solid content was up to a certain level, the emulsion displayed superior stability, more or less than that level, it showed various decline. As fumed silica was modified by cationic surfactants, the particles changed from hydrophilic to hydrophobic, with emulsion stability altered. When the compound of CTAB-SiO2and betonies was used as a stabilizer, the particles undergone slight flocculation, which induced the improvement of emulsion stability, however, the droplet size was3.8times as large as that solely stabilized by EP-1.The investigation of synergies of solid particles and emulsifier played a remarkable influence on the exploitation of new products and improvement of product function. The experiment results showed that it will make a change on emulsion type once certain amount of emulsifier was added into the emulsion stabilized by solid particles and the emulsion stability enhanced as adjusting their ratios, which even led to the decrease of droplet size. This synergy mainly reflects at two aspects:first, their competitive adsorptions affected the irreversible adsorption of solid particles; the other was that emulsifier molecules may be adsorbed on the surface of solid particles, further promoting the hydrophilic-lipophilic balance of solid particles.The mechanism of epoxy resin emulsified and stabilized by solid particles was explored, at the same time, stable and fine emulsion was produced. Finally, waterborne coating derived from this emulsion which acts as basic film materials was developed.