In the present paper, the results of viscosity measurements in dilute solutions of microcrystalline chitosan (MCCh) with poly(vinyl alcohol) (PVA) of different degrees of hydrolysis are presented. Microcrystalline chitosan is blended with poly(vinyl alcohol) in aqueous 0.1 MCH3COOH/0.2 M NaCl. Viscosity measurements of dilute polymer solution were carried out in an Ubbelohde capillary viscometer. The final result depends on (I) the thermodynamic goodness of the solvent, on (II) the applied extrapolation method used for determination of the interaction parameters, on (III) the assumed miscibility criteria, on (IV) the degree of hydrolysis of PVA, and on (V) the blend composition.
The article presents method of extracting lignin from hardwood and softwood after chemical treatment. Lignin fractions were extracted from black liquid (the by-product of pulp and paper industry), in a different reaction environment. Biopolymer composites were obtained by combining extracted lignin fraction and microcrystalline chitosan, which can be used as preparations for innovative biopolymer materials that are applicable in medical and hygienic products. The studies were performed in order to evaluate MCCh/Lignin composites to suitability to construction of dressing materials in the form of sponges. The MCCh/Lignin composites were tested for different properties: mechanical, sorption and absorption. The obtained lignin fractions and MCCh/Lignin composites were characterized by different structures and chemical purity as confirmed by FTIR spectra.
L-S-nitrosocysteine formation in EAT tumor cells and normal CRL-1636 cells incubated with microcrystalline chitosan was confirmed by RP-HPLC. The metabolite was identified based on UV-VIS spectra. The formation of L-S-nitrosocysteine in EAT tumor cells contributes to decreasing the level of L-cysteine in these cells. L-cysteine as an effector of the bifunctional M2 isoenzyme of pyruvate kinase (PK) initiates its histone kinase activity, which is responsible for histone H1 phosphorylation. A decrease of L-cysteine level in EAT tumor cells contributes to lack of histone H1 phosphorylation by the M2 PK isoenzyme and by the same token to inhibition of EAT cell proliferation.
In the present paper, the results of thermal analysis (DSC and TGA) and atomic force microscopy studies of microcrystalline chitosan (MCCh) with poly(vinyl alcohol) (PVA) are presented. Microcrystalline chitosan is blended with poly(vinyl alcohol) in acetic acid solution and this solution is cast to prepare the blend film. From thermal curves the thermal transitions: Tg, Tm and characteristic temperatures of decomposition: Tdi, Tmax have been determined and compared. The influence of the degree of PVA hydrolysis on the thermal properties of blend systems has been discussed. The surface properties of the MCCh and PVA films and their blends have been studied by tapping-mode atomic force microscopy (AFM). The changes of topography images were considered by determining the root mean square (RMS) deviation in the image data. The obtained results suggested that in solid MCCh/PVA mixtures the components are poorly miscible.
The article presents a method of extracting galactoglucomannas (GGMs) from softwood (spruce). GGMs were extracted using thermal and enzymatic treatment in an aqueous environment. The extracted GGMs, depending on the extraction method, were characterized by different composition of simple carbohydrates i.e. glucose, galactose and mannose, as well as by the average molecular weight. Evaluation of the composition of GGMs obtained was performed using GC/MS and SEC. Biopolymer composites were obtained by combining GGMs and microcrystalline chitosan (MCCh), which can be used as preparations for plant protection and growth stimulation. The studies were performed in order to evaluate biological activity of composites based on Petri dish test in which their ability to stimulate seed germination of selected plants was estimated. The effect of plant growth stimulation depended on GGMs composition of simple carbohydrates. GC/MS and SEC chromatographic tests and 13C NMR analysis enabled to establish the composition and structural changes of the obtained GGMs and biocomposites
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.