Preparation,Characterization And Loading Properties Of Cassava Starch Aerogels

Aerogels are synthetic porous lightweight materials derived from sol-gel materials with unique properties such as high porosity,specific surface area,low density,low thermal conductivity and low dielectric constant,which make them promising for applications in energy storage,adsorption,thermal insulation,flame retardancy,etc.Preparations of starch aerogels are simply prepared and have many potential uses.Meanwhile,the raw materials are cheap,easy to be obtain and renewable.Therefore,starch aerogels have gained more and more attentions.In this thesis cassava starch aerogels were prepared by sol-gel and freeze-drying.The structure and properties of cassava starch aerogels were characterized by scanning electron microscope(SEM)、Fourier Transform Infrared Spectroscopy(FT-IR)、BET,and so on.The effects of starch concentration,gelatinization temperature,chitosan addition and crosslinking agent on the structure and adsorption properties of cassava starch aerogels were investigated.The main research contents and conclusions are were follows:(1)Cassava starch aerogels had three-dimensional pore structure.When the concentration of cassava starch was 15%and the gelatinization temperature was 95℃,the specific surface area of cassava starch aerogels obtained was 1.12m~2/g,and the average pore size is 5.16 nm.The adsorption properties of cassava starch aerogels were related to their microstructure.The results showed that the adsorption of methylene blue on cassava starch aerogel was quasi-second-order kinetic model and belongs to chemisorption.The results of isothermal adsorption model showed that the adsorption was more in line with the Langmuir model.The monolayer adsorption capacity of cassava starch aerogel is 121.64 mg/g by fitting calculation.(2)The surface area of the chitosan-cassava starch composite aerogel was between 0.41-1.22 m~2/g and the average pore size was 6.19-69.78 nm.The adsorption kinetics showed that the adsorption process of methylene blue on chitosan-cassava starch composite aerogel was more in accordance with the quasi-second-order adsorption kinetics model and belonged to chemisorption.The fitting results of adsorption isotherm curves showed that the adsorption process was more suitable for Langmuir model at 40℃～60℃,and the monolayer adsorption capacity of aerogel increased with the increase of temperature.(3)The cassava starch aerogel(SA) and chitosan-cassava starch composite aerogel(C-SA)could effectively adsorb and retain paracetamol.In vitro loading tests showed that,drug release rate of drug-loaded aerogels was mainly affected by p H.In contrast,C-SA has better slow release performance.The results of release kinetics model fitting show that the in vitro release kinetics of SA and C-SA was more in accordance with the Korsmeyer-Peppa equation,The correlation coefficient R~2were obviously better than other kinetic equations,and the n in the model index were less than 0.45,indicating that the prepared drug-loaded aerogels mainly release drugs by Fickian diffusion in two different release media.