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Albu M.G.,National RandD Institute for Textile and Leather | Vuluga Z.,National RandD Institute for Chemistry and Petrochemistry | Panaitescu D.M.,National RandD Institute for Chemistry and Petrochemistry | Vuluga D.M.,Cd Nenitescu Of Romanian Academy | And 2 more authors.
Central European Journal of Chemistry | Year: 2014

The aim of this paper was to prepare composites of bacterial cellulose (BC) and collagen to evaluate both the effect of collagen on the morphological, mechanical and thermal properties of BC and the effect of BC on the thermal stability of collagen for designing composites with increased potential biomedical applications. Two series of composites were prepared, the first series by immersing BC pellicle in solutions of collagen obtained in three forms, collagen gel (CG), collagen solution (CS) and hydrolysed collagen (HC), followed by freeze drying; and the second series of composites by mixing BC powder in solutions of collagen (CG, CS and HC), also followed by freeze drying. The properties of obtained composites were evaluated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), mechanical tests, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results revealed that BC acts as a thermal stabilizer for CS matrix, while with CG matrix it interacts synergistically leading to composites with improved properties. On the other hand, the BC sheet impregnated with collagen has a significantly improved thermal stability. Collagen (as HC, CS or CG) has also a positive influence on the mechanical properties of lyophilized BC sheet. A four times increase of modulus was observed in BC/HC and BC/CG composites. and an increase of 60 times for BC/CS. The spectacular increase of elastic modulus and tensile strength in the case of BC/CS composite was explained by the easier penetration of collagen solution in the BC network and impregnation of BC fibrils as revealed by SEM and AFM analyzes. [Figure not available: see fulltext.] © 2014 Versita Warsaw and Springer-Verlag Wien. Source

Craciun G.,National Institute for Laser, Plasma and Radiation Physics | Ighigeanu D.,National Institute for Laser, Plasma and Radiation Physics | Manaila E.,National Institute for Laser, Plasma and Radiation Physics | Stelescu M.D.,National RandD Institute for Textile and Leather
Materials Research | Year: 2015

The goal of the paper was to prepare a class of flocculants by free-radical copolymerization of acrylamide with acrylic acid in aqueous solutions in the presence/absence of potassium persulphate as initiator. Reaction medium was submitted to electron beam treatment of 0.6 to 1.5 kGy in atmospheric conditions and at room temperature. Because of the complexity of reaction mechanisms involved in radio-induced polymerization, was necessary to establish the connection between absorbed dose and initiator concentration, both of them very important in free radical production. Unlike the conversion coefficient and residual monomer concentration, intrinsic viscosity and Huggin's constant are sensitive to the initiator concentration variation for all used irradiation doses. The copolymerization was confirmed by FTIR measurements. The flocculation characteristics were evaluated in 0.2 wt % kaolin suspension at room temperature using different polymer dosages between 0 to 10 ppm. High flocculation efficiency was obtained using the polymer having high values of intrinsic viscosity, molecular weight and radius of gyration. © 2015. Source

Zainescu G.,National RandD Institute for Textile and Leather | Albu L.,National RandD Institute for Textile and Leather | Deselnicu D.,Polytechnic University of Bucharest | Constantinescu R.R.,National RandD Institute for Textile and Leather | And 3 more authors.
Materiale Plastice | Year: 2014

Currently the leather industry has to face very high costs to treat and eliminate wastes. Therefore, the aim is to treat organic waste (protein and cellulose) by biochemical processes in order to be recycled in industry and agriculture. All treatments applied to waste mainly aim at substantially reducing environmental pollution. Worldwide research on leather recycling is directed towards obtaining protein composites by biochemical treatments using microorganisms/enzymes and obtaining protein hydrolysates and protein binders with different uses. Leather, even in the form of waste, is a valuable protein source for many areas: leather industry, automotive industry, agriculture, animal husbandry, pharmaceuticals, cosmetics, etc. Organic biopolymers are a source of raw materials for agriculture, as protein waste composition provides sufficient elements to improve the composition of and remediate degraded soils, and plants can benefit from elements such as nitrogen, calcium, magnesium, sodium, potassium, etc. This paper presents a new pilot-scale technology for biochemical hydrolysis of tannery waste and obtaining protein biocomposites - multicomponent systems of protein and cellulose biopolymers with application in the footwear industry and in agriculture for the remediation of degraded soils. Source

Surdu L.,National RandD Institute for Textile and Leather | Stelescu M.D.,Romanian National Institute for Research and Development in for Textile and Leather | Manaila E.,National Institute for Laser, Plasma and Radiation Physics | Nicula G.,National RandD Institute for Textile and Leather | And 5 more authors.
Bioinorganic Chemistry and Applications | Year: 2014

This paper presents the improvement of the antimicrobial character of woven fabrics based on cotton. The woven fabrics were cleaned in oxygen plasma and treated by padding with silver chloride and titanium dioxide particles. The existence of silver and titanium on woven fabrics was evidenced by electronic microscope images (SEM, EDAX) and by flame atomic absorption spectrophotometry. The antimicrobial tests were performed with two fungi: A Candida albicans and Trichophyton interdigitale. The obtained antimicrobial effect was considerably higher compared to the raw fabrics. Treatment of dyed fabrics with a colloidal solution based on silver chloride and titanium dioxide particles does not considerably influence colour resistance of dyes. © 2014 Lilioara Surdu et al. Source

Iordache O.,National RandD Institute for Textile and Leather | Stanculescu I.,Horia Hulubei National Institute of Physics and Nuclear Engineering | Plavan V.,Kiev National University of Technology and Design | Miu L.,National RandD Institute for Textile and Leather
Proceedings of the 4th International Conference on Advanced Materials and Systems, ICAMS 2012 | Year: 2012

This study will give a better insight on how irradiation can be used to treat and preserve delicate historical objects by clearing them of contaminants such as insects, fungi and bacteria. Historic and culturally important objects are at risk of microbial deterioration. Microbial deterioration ofheritage materials occurs primarily through the formation and growth of biofilms-microorganisms attached to a surface and embedded within a microbial produced polymer matrix. Gamma irradiation is used to kill contaminants and bacteria that may infest old artifacts, withoutaltering or damaging the original composition of the artifact. This radiation technique offers the most delicate and reliable method of disinfecting old or fragile cultural heritage materials; it helps o conserve them and paves the way for restoration. This research is meant to give support to a ew research which should investigate the effect of various doses of irradiation on both heritage rtifacts and microbial strains that usually affect these artifacts. Source

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