Synthesis of mesoporous silica materials using the reactive urea-formaldehyde resin polymerized in situ as template

A simple one-step procedure was described for the synthesis of mesoporous monolith and composite sphere, in which hydrolyzation of tetraethyl orthosilicate and polymerization of urea with formaldehyde occurred at the same time. The analysis of the liquid nitrogen adsorption demonstrated that the pore sizes of the monoliths and the composite spheres were both uniform. Morphologies of the composite spheres characterized by SEM were smooth or of network, which depended on the relative concentrations of the reactants. As the molar ratio of formaldehyde to urea exceeded the limit of 2.0, the synthesis by varying initial concentration of the reactants yielded the monoliths with controllable pore sizes. From the analysis of the FTIR and DTA, the urea-formaldehyde resin with branched chains in its molecular structure was considered as an inducing agent in the pore formation of the monolith.