| Starch is a kind of polymer material, which has the advantagewide of source, low price, non-toxic and renewable.and is widely used in papermaking, textile, food, petroleum, pharmaceutical and other industries, but owing to its low mechanical strength, poor stability,which make it more and more do not adapt to the needs of production, therefore, the starch was modified to expand its scope of application. β-cyclodextrin,which is Cyclic oligosaccharide, is obtained by the fermentation of starch through glucosyltransferase, the whole process has no water molecules involved,is composed of 7 glucose units connected end to end. β-cyclodextrin can generate inclusion complexes with some chemical compound, but these chemical compound should have the hole with size compatibility for β-cyclodextrin.composite microspheres cross linked by cyclodextrin and starch is a kind of functional polymer materials, which is modified with cyclodextrin, modified form of starch by means of chemical bonding. Relatively simple starch microspheres or β-cyclodextrin microsphere, composite microspheres prepared not only retains the β-cyclodextrin monomer inclusion, also with the adsorption capacity of more powerful, which will make it have important research value in some ways of essence and curing, separation and enrichment of metal ions.(1)The synthesis of composite microspheres cross linked by cyclodextrin and soluble starch was in the inverse emulsion polymerization method, which made cyclodextrin and soluble starch as raw materials, N, N-methylene bis acrylamide(MBAA) as the crosslinking agent, K2S2O8/ Na HSO3 as the initiator, the amount ratio of Span-80 and Tween-20 as emulsifier, oil phase and liquid paraffin as dispersant, Optimization of the test of the synthesis process is accomplished through the single factor experiment.The object to be measured is characterized by FT-IR analysis, XRD analysis and TGA, the experimental results show that the required composite microspheres had be formed by β-cyclodextrin and soluble starch, The micro morphology, specific surface area, particle size distribution and water absorption property of composite microspheres were determined by SEM analysis, particle size and swelling coefficient,the experimental results show that: the synthesized composite microsperes is spherical, particle size distribution obeys normal distribution, composite microsphere swelling coefficient is between 1.76-4.29, composite microsperes has strong adsorption capacity.(2)Through the single factor experiment to study the effects of different conditions on adsorption capacity of composite microspheres to jasmine essence, Comprehensive consideration of adsorption performance and cost factors show that, volume fraction of jasmine essence was 30% and adsorption temperature was 50℃, adsorption time was 3h,these would the best adsorption condition; Through the FT-IR analysis, XRD analysis and TGA analysis demonstrated that jasmine essence can well into the composite microsphere cavity, reach the adsorption effect of certain. Through a comparative study of starch microspheres and composite microspheres on the adsorption properties of jasmine essence shows that composite microsphere adsorption ability is better, through the release performance of the composite microspheres to jasmine essence proved the sustained release properties of composite microspheres is excellent,and the composite microspheres is a kind of flavor encapsulation carrier,which is non-toxic and economic.(3) 2-mercapto propionic acid / β-cyclodextrin inclusion compound was prepared in the saturated water solution method, the determination of the content of inclusion of 2-mercapto propionic acid was by ultraviolet spectrophotometry, Optimization of the inclusion process was through orthogonal experiment,the results showed that:m(β-cyclodextrin):m(2-mercapto propionic acid)=12:1, inclusion temperature was 40℃, inclusion time was 5h, the inclusion rate would reach 74.95%.To verify the structure of the inclusion compound of infrared spectroscopy was used microscopy, scanning electron microscopy, UV spectrophotometry.(4)The structure performance test of composite microspheres was through scanning electron microscope,Fu Liye transform infrared spectrometer,X- ray diffraction,the experimental results show that thiol functionalized microspheres had been successfully prepared,comparing the starch microspheres, composite microspheres and mercapto compound microspheres in the same condition of Ag+ adsorption capacity, its show that mercapto compound microspheres did have higher adsorption capacity to Ag+. The best adsorption acidity of microspheres on Ag+ is in p H=5, and when the adsorption time was 40 min,the adsorption would reach a saturation, In all adsorption process, the two stage adsorption kinetics equation could fit high correlation, and chemical adsorption is the main adsorption on adsorption to Ag+. At room temperature, adsorption isotherm of thiol functionalized microspheres on Ag+ was with the Freundlich adsorption isotherm model and Langmuir isotherm model deviation,which illustrated the synthesized microsphere has strong adsorption capacity, and when the n is greater than 1, indicated that the adsorption of thiol functionalized microspheres on Ag+ was the preferential adsorption. |
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