Modification Of Mesoporous Silica Materials And Their Humidity Control Properties

Environment relative humidity is important for our daily life and industry. The changes ofenvironment relative humidity cause the negative consequences and difficulty regulation tocultural relics, drugs, jewelries and so on. Organic cultural relics are more sensitive to environmentrelative humidity, such as fabrics. Formerly, more attention was paid to absorption (desorption)rate and amount. We hope to prepare a kind of humidity control materials, which has a high levelof absorption rate and amount. In previous years, our group has prepared8different kinds ofhumidity control materials, such as composite humidity control paper, composite humidity controlpaperboard, the porous composite resin and so on. However, after application, we have anknowledge that the stability and repeatability of materials are more important than absorption(desorption) rate and amount. Because polymer materials, inorganic mineral materials andinorganic/organic composite materials have characters of poor stability and controllability ofstructure, the stability of humidity control properties are impossibleAccording to the special requirements of f textile cultural relics, a mesoporous silica withhexagon pore structure was made. The modification methods were metal doping and porebearizing. The effect of pore structure on humidity control properties was discussed. Besides, bydiscuss the relationship between absorption amount and equilibrium humidity as a reference ofhumidity control accuracy, we can evaluate humidity control properties comprehensively. Theconclusions are as following.（1）SBA-15is prepared in acidic medium, with P123as template. It has hexagon porestructure, with high specific surface area and entrance. The average pore size is6.03nm.Equilibrium moisture is59.7%, which in the humidity range of textile cultural relics. Al-SBA-15is made by one step and post-treatment. The equilibrium moisture of most samples is more than60%. However, the equilibrium moisture of samples of one-step Si/Al=10and after-treatmentSi/Al=50is less than SBA-15.（2）MCM-41ispreparedinalkalinemedium,withCTABastemplate.Thechoiceofalkalinemedium, temperature and reactant dosage would change surface morphology, mesoporous order,particle size and dispersion of samples. a series of MCM–41with different pore diameters weremade by addition of TMB. The several samples of nitrogen isothermal adsorption-stripping belong to Langmuir Ⅳ type. Nitrogen isothermal adsorption–desorption curves of samples belong toLangmuir Ⅳ style. With the increase of TMB amount, pore diameters gradually increase, whilepore size distribution, crystal cell parameters and the intensity of the diffraction increase firstly,and then decrease.（3）Compared to other samples, when (TMB)/(CTAB) is2.5and5.0respectively, thesamples has good performance and humidity control accuracy. The equilibrium moisture is49.3%and50.1%, respectively.In this paper, the humidity control material has the characters of simple technology, goodhumidity control properties, stability and repeatability of humidity control properties. It can beused to create a clean and humidity storage environment for cultural relics.