Hydrothermal Synthesis And Characterization Of Melamine-formaldehyde Resin Microspheres

Carbon microspheres with a high packing density, good flow ability, high mechanical strength, large specific surface area and other advantages have the advantages of other carbon materials can not match because of their unique spherical structures, they also have been applied to electrode materials, catalyst carrier, adsorption, drug delivery and other fields.The melamine resin microspheres were prepared by hydrothermal method, including of one-step and two-step preparation. We did not add PVA into the system, and only by adjusting the hydrothermal synthesis conditions, the melamine resin microspheres can be made. One-step method was to directly mix a certain amount of melamine and formaldehyde into deionized water under hydrothermal conditions. Two-step method was to prepare the hydrxymethylol melamine firstly,and to hydrothermally deal with the prepolymer secondly to prepare microspheres.We discussed the influence of p H value, retention time, concentration, molar ratio of raw materials on microspheres. By using scanning electron microscopy(SEM), elemental analysis(EA), infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), thermogravimetry(TG) and other methods, we tested and analyzed the particle sizes, morphologies, structures and composition, and supposed the mechanism of the formation of melamine resin microspheres.The results showed that the particle sizes of melamine resin microspheres using melamine and formaldehyde as raw materials by hydrothermal method were between 0.1-10 μm, and the resin microspheres were with spherical integrity; by adjusting the reaction conditions, we could prepare monodisperse melamine resin microspheres of about 4 μm with smooth surface and good sphericity. As for the formation mechanism, one-step is Lamer model mechanism, and the two-step is the mechanism of seed polymerization.