Synthesis and Characterization of Silica Monoliths Impregnated with Chitosan

The development of new materials containing both organic and inorganic structures is of great interest with respect to achievement of obtaining the special properties, and the sol gel process has provided new opportunities for making such materials. In this paper, new SiO2-chitosan hybrid monoliths were produced by this technique, using biopolymer chitosan as the organic species to be impregnated to the inorganic material (SiO2) to produce a versatile material for immobilization of enzymes as another inorganic catalitic system application. The chitosan have good biocompatibility, biodegradability and various biofunctionalities. Although chitosan is a polymer with unique chemical and biological properties, it seems to be lack of mechanical strength. On the other hand the SiO2 is a material that presents stronger mechanical strength, thermal stability, high porosity and lower cost. The procedure experimental for hybrid monoliths was carried in two stages: 1- The sol-gel monoliths were prepared based on method described by Gómez; 2005. 2-The chitosan was incorporated to the monoliths to five different concentrations to 25, 50 and 70°C for immersion processes. All materials were characterized by FT-IR, SEM, X-ray diffraction (XRD), surface area and the chitosan absorption percentage. FT-IR results showed the characteristic vibration bands of hybrid material as OH, Si-O-Si, Si-OH and NH2. The monoliths surface presented the highest quantity of chitosan and the homogeneous surfaces at a micrometer scale. The samples obtained to 50 and 70 °C showed the better adsorption process and the surface area was 452.99 m2/g and size pore of 18Å. The results reported in this study provide a useful and simple route for developing hybrid natural-synthetic polymers, these materials presented satisfactory properties.