Preparation And Application Of Porous Melamine-formaldehyde And Urea-formaldehyde Resin Materials

Urea-formaldehyde resins and melamine-formaldehyde resins are two typical amino resins, which have some advantages such as low production cost, simple preparation process, outstanding flame retardant property and excellent thermal stability. It has been widely applied in the fields such as paint, binder, mold products, electrical equipment.In this article, urea formaldehyde resin and melamine resin were used as matrix to prepare urea-formaldehyde resins and melamine-formaldehyde resins porous materials through solubility difference method which was according to the different solubility of porogen agent in water, resin and organic solvent. The solubility difference method compared with the traditional porous materials has the following advantages:(1) The porogen agent do not need to be prepared into specific shape and size and just was directly dissolved in an organic solvent such as acetone, absolute ethanol, then was added to the resin solution. Because of the solubility of porogen decreased suddenly, its crystalline particles began to precipitate in the resin system. After the resin cured, the porogen is removed to achieve the purpose of pore; (2) The porogen agent and organic solvent can be used circularly after the porogen is removed with an organic solvent and then separated from the organic solvent; (3) Preparation of porous materials does not produce waste acid and waste alkali, which reduces the production cost and environmental protection; (4) Because of that strong acid and alkali have not been used to remove the porogen, so the prepared porous resin material contains large amounts of amino and other active functional groups which is propitious for porous materials to get graft modification and practical application.In this article, urea-formaldehyde resins and melamine-formaldehyde resins porous materials were used as adsorbent to adsorb heavy metal ions. Research showed that, the adsorption process of urea-formaldehyde resins and melamine-formaldehyde resins porous material for cadmium ion follows Langmuir and pseudo-second-order model. Many kinds of interference such as Pb(â…¡), Cu(â…¡), Cr(â…¢),Na+and K+has little effect on removal of cadmium ion. In addition, melamine-formaldehyde and Urea-formaldehyde resins porous material also has a good adsorption capacity and removal rate for Pb(â…¡), Cu(â…¡), Cr(â…¢). Moreover, melamine-formaldehyde and Urea-formaldehyde resins porous material after many repeated use is still has a good removal rate and adsorption capacity on the cadmium ion.In addition, this work also includes preparation of melamine resin microspheres, the preparation process of the traditional microspheres uses a lot of dispersants, emulsifiers and surface active agent. But these active agent is difficult to completely remove in a subsequent process, and there are still a lot of surfactant coated on the surface of the microsphere which will impact the graft modification of microspheres and the following application. In this thesis, smooth surface, uniform melamine resin microspheres were prepared without surfactants, while investigating the influence of molar ratio of reactant, reaction time, reaction temperature, proportion of raw materials and water on the microspheres morphology, size and other properties. These microsphere have important application prospect in the fields such as catalyst carrier, adsorption.