Preparation And Properties Of Composite Aerogel Based On Bacterial Cellulose

Cellulose aerogels have many excellent features such as high porosity, high specific surface area and easy degradation. Its three dimensional porous network structure has unique value of application in the field of new materials. Polyvinyl alcohol bearing styrylpyridinium group (PVA-SbQ)/bacterial cellulose (BC) composites were prepared via UV cross-linking and freeze drying. A method of chemical vapor deposition was used for silanization modification of composite aerogel to obtain the effect of hydrophobic oleophilic. We made a preliminary discussion on its absorption properties, oil-holding properties and recycling abilities. We also proposed a suction mechanism of the arepgels. The main research contents and conclusions are as follows:BC/PVA-SbQ composite aerogels were prepared via UV cross-linking and freeze drying. The composite aerogels’surface morphology, the internal pore structure, thermal stability and mechanical properties were charactered with many testing methods, such as scanning electron microscope (SEM), automatic specific surface area analyzer (BET), X-ray diffraction (XRD) and the tensile breaking strength tester. Surface wettability of composites were studied by DCAT-21 surface tension meter. The results indicate that after the combination of PVA-SbQ and BC, fiber structure gradually disappeared, turning to membrane with the increase of PVA-SbQ concentration; Due to the introduction of PVA-SbQ, crystallinity of bacterial cellulose was decreased; Thermal stability of the composite aerogels were improved by strong hydrogen bonding interaction between two molecules; At lower concentrations of PVA-SbQ, breaking strength of the composite aerogels were increased; When the PVA-SbQ concentration is too high, BC as the dominant system in the composite system weakens, leading to decreased fracture strength of composite materials; Due to hydrophilic of PVA-SbQ, the absorbent properties of the composite aerogels was improved.To optimize liquid absorption of the composite material and control of composite solution, the method that bacterial cellulose hydrogel dispersed into nano cellulose suspension by high-speed homogenizer machine was first proposed after repeated experiments. A composite gel was formed by bacterial cellulose and PVA-SbQ solution by UV cross-linking, then PVA-SbQ/BC composite aerogels were obtained by freeze-drying. Different concentration of PVA-SbQ on the influence of the pore structure, crystal structure, mechanical properties of composite aerogels, and the dynamic of the water and oil absorption process were analyzed. The results show that the composite aerogels exhibited a interpenetrating pore structure, high porosity (94%), low density (0.02 g/cm3). It has a cell wall structure and sticky with each other; With the increase concentration of PVA-SbQ, the Young’s modulus and fracture strength of the composite aerogels improved; the composite aerogels have good adsorption properties; It provided theoretical basis for the study of dynamic wettability of materials through the analysis of the adsorption process of composite aerogel.Composite aerogels were modified by chemical vapor deposition to get hydrophobicity. The preparation of hydrophobic composite aerogels still have three-dimensional porous network structure, the maximum oil absorption capacity of engine oil, silicone oil, soybean oil was 51 g/g,52 g/g,42 g/g, respectively; The composite aerogel has good structural stability can be used to absorb oil repeatly; Composite aerogels was prepared have good oil-water separation properties and also have a high separation efficiency for oil slick.