In this paper,molecular dynamics simulation was applied to synthesize a layered structural color from Konjac glucomannan(KGM) and the effect of particle diameter and temperature were investigated. A series of methods such as high voltage electric field treatment,the transfer matrix method and the CIE standard colorimetric system were simulated to obtain the chromaticity coordinates and to analyze the color changes of KGM particles. The results revealed that as the particle diameter increases,the structural color of KGM particles deflects towards the yellow wavelength within the visible spectrum; and as the reaction temperature rises,the structural color deflects towards the blue and violet wavelengths within the visible spectrum.
Konjac glucomannan(KGM)was aminated by 2-chloroethyl-amine(CEA)as reagent so as to study the influence of concentration of CEA(based on the amount of KGM),concentration of NaOH,reaction time and temperature on the extent of amination.And the molecular simulation technology was adopted to analyze the conformation stability of aminate(AKGM).The results indicate that when the amount of CEA is higher,the extent of amination is higher.The optimum concentration of NaOH,reaction time and temperature are 10%NaOH,70℃and 45 min,respectively.IR shows KGM is successfully aminated.The conformation of AKGM is in a random clew-like shape.
WANG Li-XiaWEN Cheng-RongWU JingLIN Hai-DongHU Shu-GuoPANG Jie
To understand the effect of plasma treatment on the Konjac glucomannan film, the nitrogen plasma was injected into the film by ion beam injection machine in this study. The structures and properties of Konjac glucomannan film after plasma treatment were analyzed by Infrared spectroscopy, Raman spectrum, X-ray, ect. The result showed that nitrogen groups appeared in the KGM molecular chain and part of this chain fractured, and the number of hydrogen bonds increased after the treatment of plasma. The form of KGM molecule remained amorphous non-crystalline state, but the crystalline region was increased and became more ordered. The mechanical property of tensile strength and breaking elongation was improved, while the WVP was decreased. The nitrogen groups were grafted on the KGM molecular chain after plasma treatment, which led to the improvement of the properties of KGM film.
The influence of additive Konjac Glucomannan (KGM) in a variety of con- centrations on the crystallization morphology and structure of calcium oxalate (CaOxa) has been investigated by infrared spectroscopy, scanning electron microscope, X-ray diffraction and so on. The results showed KGM can complex with the Ca2+ions; low concentration KGM prevents CaOxa from aggregating, raises the concentration of ions in the solution, reduces the quantity of crystals and inhibits their growth, and the crystals are round and blunt; while high concentration KGM promotes the growth of crystal, which appears in sheet-like or irregular shape. Only CaOxa monohydrate was observed in a certain system with or without the presence of KGM.
The dynamic changes of the complex network and the material form and function were actuated by the molecular chains. The interaction behavior between molecular chains was difficult to illuminate because the dynamic changes of macromolecules were observed difficultly by normal spectrum method and the methods to test and evaluate the complex network evolution prediction and intervention are rare. The mathematic model of domino offect of molecular chains was established based on the topological structure of molecular chain aggregation of Konjac glucomannan, and the molecular entanglement mechanism of Konjac glucamannan blends was studied through molecular simulation and knot theory analysis combined with experimental verification. The results suggested that two network models(topological entanglement and solid knot) of Konjac glucomannon blends were formed through hydrogen bond nodes. The topological entanglement was strengthened with the increase of concentration and the form of molecular chains was Gaussian chain which could not allow traverse moving owing to the intermolecular cross and entanglement and the shield of intramolecular interaction. Besides, the structures of Konjac glucomannon blends became more stable due to the solid knot. Both of them were verified by the experimental results. This experimental method simplifies the microscopic description of Konjac glucomannon, and there is important guiding significance of the experimental results for the prediction and control of polysaccharides' structure and function.
An ultra-light and high porosity nano microfibril aerogel was prepared from konjac glucomannan(KGM) by the electrospinning and freeze-drying. The structure of aerogel was analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD) while the density and compressive strength of the samples were studied separately. Results reveal that porous network structure of the KGM nano microfibril aerogel is constructed by intermolecular hydrogen bonds in random and interpenetrate way. The nano microfibril structure presents in the KGM aerogel,which is an important reason of its high density and compressive strength. There is a potential application for this unique nano microfibril aerogel in the absorption of biodegradation bacteria to solve problems in marine oil spill pollution.
