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Novak I.,Slovak Academy of Sciences | Popelka A.,Slovak Academy of Sciences | Popelka A.,Qatar University | Luyt A.S.,University of the Free State | And 9 more authors.
Surface and Coatings Technology | Year: 2013

Polyester foil was treated by the surface diffuse barrier discharge (SDBD) plasma at atmospheric pressure in oxygen and/or in nitrogen containing a small amount of oxygen to improve its surface and adhesive properties. Changes in a chemical structure of the polyester were analyzed by electron spin resonance (ESR) spectroscopy, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and by X-ray photoelectron spectroscopy (XPS). The changes in surface morphology were studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). A surface energy as well as an adhesion of polyester modified by the SDBD plasma to polyacrylate significantly increased. The efficiency of the modification by the SDBD plasma depends on the used processing gas as well as on the modification time. The decrease in the surface energy of polyester modified by the SDBD plasma due to hydrophobic recovery was also investigated. A correlation between adhesive properties of polyester modified by the SDBD plasma and its surface has been found. © 2013. Source


Matyasovsky J.,VIPO | Sedliacik J.,Technical University In Zvolen | Cervinkova D.,VUSAPL | Jurkovic P.,VIPO | And 2 more authors.
Journal of the American Leather Chemists Association | Year: 2012

One of the substances suitable for preparation of biologically degradable polymer composites is collagen. It is the main component of the animal tissue of leather, bones and tendons. It belongs among the most technically important fibrous proteins. The characteristic structure of collagen, with a high degree of internal organization of molecules, is the main aspect determining the mechanical properties of this tissue. Three collagen polypeptide alpha - chains are commonly screwed into regular right-handed super-spiral. These molecules are extremely rich of glycine (26 - 28%) and proline (over 15%). For the intended application native collagen is relatively difficult to be processed without modification. Collagen colloid prepared by hydrolytic decay of the conformational structure after de-amination of collagen with a shift of iso-electric point to the value < 5 was used in these experiments. Further chemical modifications was necessary, e.g. in the packaging industry, to ensure and optimize the thermal elasticity and compatibility with the tested polymers. Ethylene vinyl-acetate copolymer was used as the polymer matrix. For collagen modification, applied modifiers were based on polyhydric alcohols and amines. During the compounding process, individual compounds of the mixture were homogenized. Polymer granulates with different ratios of individual compounds in the mixture were prepared by granulation. Process-ability of the prepared granules was tested by producing foils using blowing technology. Physical and mechanical parameters of the foils were evaluated; strength, elongation, permeability to water vapor and biodegradability. The results obtained were considered mainly from the point of view of controlled biodegradation. Source


Matyasovsky J.,VIPO | Sedliacik J.,Technical University In Zvolen | Matyasovsky J.,Slovak University of Technology in Bratislava | Jurkovic P.,VIPO | Duchovic P.,VIPO
Journal of the American Leather Chemists Association | Year: 2014

Fibril proteins of leather, mainly collagen, keratin, glycoproteins, hetero-polysaccharides as hyaluronic acid are the most significant from the view of application in cosmetics. Collagen is the most widespread animal protein component of skin, tendon, bones and ligament. Keratin is the main component of hair, fur, feathers, hooves, horns and outer surface of the skin. Keratin is characterized by a high content of sulfur amino acid cysteine with a typical formation of disulfide bridges. Modified collagen is the basis for several types of test colloids, where agents for the regeneration of the skin, with a high degree of its hydration appear very promising. Originality of the research was ensured as well by the biopolymer keratin as natural anti-solar protection of skin. This knowledge is based on physiological presence of keratinocytes in leather and connected protective mechanism against the effects of the sun. The aim of this work was to develop liposome colloid systems based on biopolymers with a multifunctional effect and to obtain higher benefit of cosmetic preparations e.g. increased hydration, regeneration, protection against ultraviolet radiation, barrier protection of the skin etc. and to ensure microbiologic stability of these systems by the application of colloid silver. Samples of biopolymers, dispersions, emulsions and liposomes were evaluated by the determination of their basic qualitative parameters as viscosity, dry content matter, size of particles and stability. Hydrolysates of keratin lower surface tension from the value γ = 72.8 mN.m-1 to the value approx. γ = 55.5 mN.m-1, and therefore, research was oriented to the possibility of lower dosing of synthetic emulsifier at keeping of required stability of hydrogels and hydro-creams. Results of testing samples confirmed increased hydration of the skin and protection mainly against UVB radiation. Evaluation of disinfectant efficiency of prepared colloidal silver confirmed the bactericidal, fungicidal and sporocidal effect against a broad spectrum of bacteria, fungi and microbes. Source


Sedliacik J.,Technical University In Zvolen | Matyasovsky J.,VIPO | Smidriakova M.,Technical University In Zvolen | Sedliacikova M.,Technical University In Zvolen | Jurkovic P.,VIPO
Journal of the American Leather Chemists Association | Year: 2011

This research was aimed at determining the possible usefulness (ecologic, efficiency, and economic) of collagen material, after de-chroming, to modify polycondensation adhesives for application in the woodworking industry. The de-chroming technology of leather chromium waste was proposed in our previous work.1 In this work, condensation adhesives based on urea-formaldehyde and phenol-formaldehyde were modified with protein hydrolysates. It is known that collagen hydrolysate of chrome-tanned leather waste added to dimethylol urea clearly limits formation of relatively unstable oxy-methylene bridges which may be regarded as potential source of formaldehyde emissions. The aim of this study was to verify the change of glue joint properties in following ways: influence of collagen hydrolysate on shear strength properties of glued joints under action of water and high humid conditions; increasing the water-resistance of glued materials, development of adhesive mixtures suitable for gluing of wood at higher moisture content, influence of collagen hydrolysate on lowering the formaldehyde emissions from wood based panels. The intended sources of protein hydrolysates were solid waste from leather production (e.g. chromium shavings and chippings, hypodermic and adipose ligament, leather chippings, gelatin production and food packing). These various analytical investigations of this study confirmed significant reduction of formaldehyde emission from wood based panels, increased water-resistance of glued materials, and conforming shear strength properties of glued joints. Application of collagen from de-chromed waste allows improvement of ecologic and economic parameters of bonding processes in the woodworking industry (e.g. eliminating of harmful effects on the environment and lowering of costs at keeping required quality). Source

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