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EN
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.
EN
Poly(vinyl alcohol) films were prepared with manganous chloride (MnCl2 · 4H2O) and glycerin as complex plasticizer. The micro morphology of pure PVA film and complex plasticizer plasticized PVA films was observed by scanning electron microscope (SEM). The interaction between complex plasticizer and PVA molecules was investigated by Fourier transform infrared spectroscopy (FT-IR). The influence of complex plasticizer on crystalline, thermal and mechanical properties of PVA films was studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and tensile testing, respectively. The results showed that the complex plasticizer of MnCl2 · 4H2O/glycerin could interacted with PVA molecular and then effectively destroy the crystals of PVA. PVA films plasticized with complex plasticizer of MnCl2 · 4H2O/glycerin became soft and ductile, with lower tensile strength and higher elongation at break compared with PVA films. This is an important cause of plasticization of the complex plasticizer of MnCl2 · 4H2O/glycerin on PVA films.
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vol. 15
11 - 16
EN
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.
EN
In the present study the results of rheological measurements and atomic force microscopy (AFM) of polymer composites with montmorillonite (MMT) are presented. Chitosan is blended with synthetic polymers and inorganic additives in acetic acid solution and this solution is cast to prepare the mixture film. Flow measurements were made on a Bohlin Visco 88 rotary viscometer in the temperature range 25ºC-40ºC. The apparent shear viscosity and rheological parameters of the unmodified components and their composites were determined and discussed. Polymer films were examined using a Scanning Probe Microscopy SPM production Veeco. The obtained results suggest that the modification of several properties of polymer composites is a consequence of the interaction between the polymeric components and inorganic additives.
EN
In the present paper, results from rheological measurements and tensile tests of polymer blends containing chitosan and poly(vinyl alcohol) with different additions of an ionic liquid are presented. Flow measurements were carried out using solutions of pure polymers and their blends with and without the addition of an ionic liquid. It has been observed that the polymer solutions and their blends exhibited non-Newtonian behaviour. Rheological parameters from the power law and activation energy of viscous flow were determined and discussed. Mechanical properties, such as the tensile strength and ultimate percentage of elongation of films, have been determined and compared. This study thus shows that the addition of an ionic liquid is an effective method for improving the flexibility of chitosan blends.
EN
Surface properties of composites containing chitosan (Ch), poly(vinyl alcohol) (PVA) with hydroxyapatite (HAP) were investigated by contact angle measurements and atomic force microscopy (AFM). Thin films of Ch/HAP and Ch/PVA/HAP composites have been formed by casting methods from acetic acid solutions. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films, Ch/HAP and chitosan/PVA/HAP films were made and surface free energy was calculated. It was found that chitosan/HAP or Ch/PVA/HAP blend surface is enriched in high surface energy component i.e. chitosan. The study of composites by AFM showed a completely different morphology when compared with unmodified components. The roughness of composites increase after the addition of hydroxyapatite. This may indicates a strong interaction between the polymeric components and inorganic additive.
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