Assembly Of Konjac Glucomannan And Curdlan In The Film-forming Process

This dissertation is to konjac glucomannan(KGM) and curdlandlan(curdlan) as the substrate, the researcher observed the film formation process of two kinds of polysaccharide molecules. To investigate the relationship between the structure and properties of the membrane materials from the impact of micro structural characterization, and influence of temperature on the molecule of KGM and curdlan composite process of conformation, then put forward KGM-curdlan molecular dynamics model, to provide a theoretical basis for the KGM-curdlan blend membrane was prepared with different requirements.(1) Has a water-soluble preparation of KGM and curdlan physical blending KGM / curdlan blend film. Scanning electron microscope was used to observe the surface structure of membrane, when KGM:curdlan is 7:3(w/w), the film has smooth surface, compact and uniform. X-ray diffraction patterns indicated that KGM / curdlan destroyed the original crystal structure of the KGM and curdlan, KGM and curdlan formed a new crystal structure complexly and has good compatibility. The FT-IR spectrum showed the blending process of curdlan and KGM, interaction between molecules, mainly hydrogen bonds.(2) The mechanical properties of KGM/curdlan film on the assessment, discusses the relationship between structure and properties. SEM observation of structural changes in the membrane solution during the drying process, at first the composite membrane solution was mixed with irregular, and gradually formed a neat layered structure,finally the thin film had compact structure. In addition, it revealed that there is a big difference in tensile strength and elongation at break of the membrane preparation after mixing the solution and dried at different temperatures. TS and the EAB research suggests that, in order to maximize the good mechanical properties of blend films, KGM/curdlan mixing and drying temperature should not be below 40 °C.(3) By means of molecular dynamics simulation, it found that KGM and curdlan have hydrogen bonds with each other in mixing process and then assembled into a stable structure, atomic force microscopy and transmission electron microscopy for further validation of the results in this. By AFM, TEM analysis of molecular shape KGM, curdlan and KGM-curdlan and related structures at different temperatures, the temperature from 120 °C down to 25 °C in the process, KGM molecular conformation has not changed significantly,it can form a three-dimensional network structure. The shape of the curdlan molecule has great effect on temperature, which tended to wind into a triple helical structure from a single helix form and subsequently compact into micelles when the solution cooled from 120 to 25°C, and the length, width and height are changing. When the two kinds of polysaccharides were mixed, KGM with extended linear conformation wound around curdlan.Meanwhile KGM molecules interspersed among curdlan chains, and resulted in the formation of uniform and stable structures of KGM-curdlan in water solution.