Browsing by Author "Gaidau C."
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Item Progresses in treatment of collagen and keratin-based materials with silver nanoparticles(2013-12-01) Gaidau C.; Petica A.; Micutz M.; Danciu M.; Vladkova T.The influence of different chemical systems on the interaction of collagen at the molecular level with silver nanoparticles in collagen- based materials is a very important source of information for designing leather technologies and treatments as ecological alternatives to organic preservatives currently used. The UV circular dichroism as a scientific tool to assess mainly the secondary structure of proteins in solution proved that silver nanoparticles are able to interact with collagen in aqueous medium in the presence of some classical cross- linkers and other chemical additives similar to those occurred in collagen-based materials. The most important influence on secondary structure of collagen was observed in the case of interaction with chemically and electrochemically synthesized silver nanoparticles in the presence of basic chromium salts with or without poly(hydroxy urethane). The treatment of chromium tanned sheepskins with poly(hydroxyl urethane) and dispersion of chemically synthesized nanosilver showed the best resistance to fungi and bacterial exposure tests. These collagen-based materials containing different amounts of nanosilver were investigated by Atomic Absorption Spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy. The influence of sheepskins treated with silver nanoparticles on the wound healing process was assessed and the nanoparticles concentration seems to have a positive effect up to 370 ppm and does not influence the inflammatory process above this concentration. © Versita Sp. z o.o.Item Research on cold plasma treatment of leather and fur based materials as ecological alternative(2017-01-01) Gaidau C.; Niculescu M.; Surdu L.; Barbu I.; Vladkova T.; Dineff P.The paper presents the performances of leathers and fur skins pre-treated with cold plasma through dielectric barrier discharge (DBD) at atmospheric pressure and room temperature followed by treatment with chemical materials. The main improved properties were water repellency and flame resistance, two important characteristics for added value garments (water proof and fireman footwear), high quality furniture and automotive leather upholstery. The water drop resistance in static conditions reveals a hydrophobic effect on dermis surface induced by cold plasma pre-treatment, similar with chemical impregnation. The water resistance in dynamic conditions showed the reactivation of hydrophilic groups inside collagen and keratin based materials, similarly with other materials pre-treated with cold plasma presented in literature. The water quantity which penetrated the fur skins dermis decreased by 22.7% for the pre- treated samples with cold plasma and treated with silicon based materials as compared to samples not pre-treated with plasma. Full grain leathers pre-treated with cold plasma showed impermeable behavior and improved flame resistance. The influence of cold plasma pre-treatment was favorable for water repellency of leathers and fur skins and for flame retardant properties of different kinds of leathers.