Study On Preparation And Physicochemical Properties Of Salix Psammophila Cellulose Hydrogel

Salix Psammophila as a region of northwest China is one of the endemic species,because of its unique advantages,has a flat stubble and rejuvenation of Salix Psammophila diversity application efficiency,and is extremely important,natural cellulose is a kind of environmental friendly,raw material sources,the environment is one of the biodegradable polymer materials,and Salix Psammophila contains relatively rich in cellulose,this provides the preparation of Salix Psammophila cellulose matrix composites with convenience.The main research contents of this thesis are as follows:(1)Use nitric acid-ethanol solution to pretreat Salix Psammophila in the PTFE reactor,and then purify Salix Psammophila cellulose by sodium chlorite and alkali treatment,and explore the reaction conditions.The results showed that the optimal extraction conditions of crude cellulose were as follows:temperature 120 ~oC,solid-liquid ratio 1:35(g/m L),time100 min.The maximumα-cellulose content of crude cellulose was 67.47%.(2)Use the nitric acid-ethanol solution with hydrochloric acid-ethanol solution of two different acid alcohol solution of Salix Psammophila preprocessing,and then by acid sodium chlorite Salix Psammophila cellulose,potassium hydroxide,and then through 8 wt%hydrochloric acid hydrolysis of Salix Psammophila cellulose preparation of Salix Psammophila microcrystalline cellulose,and the extraction of each stage of the samples were characterized.The experimental results showed that the yield of Salix Psammophilamicrocrystalline cellulose was 32.95%and the crystallinity was 59.32%.(3)Using Salix Psammophila microcrystalline cellulose as raw material,nano-cellulose was prepared by purification method.Salix Psammophila microcrystalline cellulose was first hydrolyzed by 64 wt%sulfuric acid solution to prepare Salix Psammophila cellulose whiskers(CNC),and then TOCNC was prepared by TEMPO oxidation.The experimental results showed that the surface of TOCNC was more smooth than that of CNC due to the introduction of carboxyl group after TEMPO oxidation.Infrared spectrum analysis showed that obvious carboxyl functional groups appeared after oxidation,which proved that CNC had been successfully oxidized.Under AFM,both CNC and TOCNC showed short rod fibers with average diameters of 23.10 nm and 21.84 nm,and average lengths of 213.61 nm and165.69 nm,respectively.(4)To Salix Psammophila microcrystalline cellulose as raw material,TEMPO/NaBr NaClO as reaction system,explores the microcrystalline cellulose under different amount of sodium hypochlorite add the change of carboxyl content,combined with high strength was prepared under ultrasound in 1200 W series of Salix Psammophila TEMPO oxidation nano fiber,the diameter of the nanometer fiber is obtained by transmission electron microscopy(sem)is 23.39 nm,preparation of sample solution by vacuum suction filter by TEMPO oxidation Salix Psammophila nano cellulose membrane,the membrane under 800 nm wavelength,the maximum transmittance about 60%;Salix Psammophila microcrystalline cellulose was dissolved in sodium hydroxide/urea solution and mixed with TEMPO-oxidized nano-cellulose solution in a certain proportion.Using acetic acid,ethyl acetate and carbon tetrachloride as coagulation bath,Salix Psammophila microcrystalline cellulose/TEMPO-oxidized nano-cellulose aerogel spheres were prepared by suspension drop method.The results showed that the carboxyl functional groups appeared in the samples before and after dissolution,indicating that the dissolution process had no effect on the carboxyl groups.In the BET analysis,the average pore size of aerogel decreases gradually with the increase of nano-cellulose doping amount.The maximum adsorption capacity of copper ions by aerogel spheres was 165.92 mg/g.(5)To Salix Psammophila microcrystalline cellulose as raw material,epichlorohydrin as crosslinking agent,the calcium carbonate as the pore-forming agent,network structure,the first layer are formed by heat caused by hydrochloric acid solution to remove calcium carbonate macroporous Salix Psammophila cellulose hydrogel,and on this basis,the preparation of Salix Psammophila microcrystalline cellulose/acrylamide hydrogel interpenetrating network structure,and of those gel characterization testing.The experimental results show that:in the scanning electron microscope image,the surface of the interpenetrating network hydrogel presents a broken wall type channel,and the maximum swelling rate is 684.95%.During the synthesis process,there is no obvious new peak in the infrared spectrum,indicating that the first layer network structure and the second layer network structure are independent of each other.The hydrogel has good compressive tensile and shear resistance properties.