Preparation And Properties Of Sodium Alginate And Composite Gel

As a kind of natural polysaccharide polymer,sodium alginate has been widely used in the food industry,environmental engineering and biological engineering because of its good biocompatibility,stability,hydrophilic and flocculability,etc.How to extend the application of sodium alginate is a big challenge.It is possible to maximize the performance of SA through rational combination with other functional polymer materials to enable the synergistic effects of different components.In this paper the following four aspects are studied:(1)Pure SA hydrogel was crosslinked by several common metal cations to explore the effect of the preparation conditions on swelling degree.Then,graphene oxide(GO)was added to synthesize SA/GO hydrogel in order to research the effect of the dosage of GO on the swelling degree.Finally,the series of poly(N-isopropylacrylamide)(PNIPAm)hydrogel modified by SA and GO were prepared.The effect of different component on the environmental responsiveness of the hydrogel was focused.The results show that the PNIPAm/SA/GO hydrogel and PNIPAm/SA hydrogel have mechanical properties and environmental sensitivity.(2)Graphene(Gr)/SA hydrogel was prepared by the combination of hydrothermal and cross-linking method.The microstructure of the hydrogel was studied by SEM,and the mechanical strength of hydrogel was verified by the load bearing experiment.The dye adsorption performance of the hydrogel was also studied.The results show that the Gr/SA hydrogel has good adsorption properties for most common dye,and the hydrogel crosslinked by metal cation have better mechanical properties which is good for recycling.The optimal mechanical strength and adsorption performance was achieved by Fe3+ ions crosslinking.The adsorption for methyl orange(MO)was about 20 mg/g.(3)Under low temperature,PANI/SA hydrogel was prepared using ammonium persulfate(APS)as oxidant by in situ polymerization in aqueous solution.PANI/SA/GO hydrogel was synthesized by adding GO into the above system.Their microstructure,compression strength and electrochemical performance were characterized.The results show that the PANI/SA hydrogel has strong mechanical strength.GO have little impact on mechanical properties,but greatly improve the electrochemical properties of the hydrogel.The capacitance of PANI/SA/GO hydrogel is about 2.5 times as much as that of PANI/SA hydrogel.(4)SA porous sponge was prepared by freeze drying and calcium chloride as crosslinking agent,then water absorption rate and drug release behavior were characterized to study the effect of component ratio,water adsorption and voltage on its drug release.The results show that the sponge of 2.5% SA has the best water adsorption and drug release rate.With the improvement of voltage,drug release rate was increased.The hydrogel reached releasing balance within 8h and its drug release rate was about 95% under 3V.