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The aim of the present paper was to obtain epoxy nanocomposites reinforced with layered clays type nanofiller. Nanocomposites materials have been obtained through mechanical mixing of resins based on diglycidyl ether of bisphenol A (DGEBA) chemically modified with low molecular glycols filled with Cloisit type layered clays and crosslinked using 4,4 ‘diaminodiphenyl metane ( DDM)as curing agent. Epoxy nanocomposites have been obtained and characterized as compared to standard epoxy nanocomposites not only by conventional methods-physical-mechanical properties, but also by DMA tests in order to establish the degree of dispersion of the nanocaly in the epoxy matrix. Flexural strength and impact tests have shown that the reinforcement of composite materials with laminated clays leads to an improvement in their properties as compared to unmodified epoxy systems. Keywords: epoxy nanocomposite, glass transition, dynamical properties, mechanical properties

Orthodontic appliances are intraoral devices used to induce changes in relations between the teeth and the underlying bone structures. Removable orthodontic appliances, which contribute to the alignment of misaligned teeth and to the development of maxillaries, are not fixed to teeth and can be inserted/removed easily on/off the teeth of the dental arches. The aim of this study was to evaluate some characteristics of removable orthodontic appliances achieved by two different technologies (heat-curing and vacuum-forming), realised by using two dental materials (Superacryl Plus-SpofaDental thermo-cured acrylic resin and Biocryl® C and Biocryl® M -Scheu thermoplastic materials). The study included 123 adolescent patients, to which were manufactured one or two removable orthodontic appliances, on one or both of the dental arches. A total of 141 removable orthodontic appliances were manufactured for the selected adolescent patients. The manufacturing of all types of removable orthodontic appliances followed the same technological procedures, specific to each type of used material. The results of the study demonstrate that the aesthetic effect of the two dental materials presented different results, and the best results were observed at the orthodontic appliances achieved by the vacuum-forming technology, using Biocryl® C and Biocryl® M–Scheu thermoplastic materials. Keywords: removable orthodontic appliances, materials, technologies, aesthetics

Relaxation time reflects dynamic phenomena in the early stages of electrospinning after an abrupt application of an external electric field. Experimental counterpart of relaxation times, i.e., characteristic hydrodynamic times, have been measured using a laboratory device designed especially for this kind of experiments. The experiments supporting the hypothesis are carried out with aqueous solutions of poly (vinyl alcohol) of various concentrations. Experimental data are compared with theoretical predictions of relaxation times aiming to a deeper analysis of dynamic phenomena during the earliest stages of electrospinning. Qualitative and quantitative comparison of theoretical and experimental relaxation times determined that characteristic hydrodynamic times are encouraging. Moreover, the experimental apparatus for characteristic hydrodynamic time investigation revealed regular discharges in a spinning zone of the electro-spinner that imminently precede electrospinning jet appearance. Results of the work contribute to a deeper understanding of a spin-ability of polymeric solutions using electrospinning and are an inspiration for new electrospinning variants. Keywords: nanofibers, needleless electrospinning on the rod, polyvinyl alcohol aqueous solutions, rod, relaxation time

Young’s modulus needed for realizing a numerical analysis model with finite elements dedicated to studying static strain on an artificial bone, made out of composite material (polyester resin reinforced with fiber glass) is determined, as well as Young’s dynamics modulus needed for analysis through numerical simulation of dynamic strain applied to the same structural element (vibrations, shock). Both in, static and dynamic conditions, two methods are utilized in measuring the materials elastic characteristics. Keywords: Young’s modulus, artificial bone, composite material, numerical simulation

The paper presents the obtaining of new biodegradable plastic materials using collagen hydrolysates. As raw materials, to transform into collagen hydrolysates, untanned leathers’ wastes were used. The influence of chemical structure and ratio of protein material on thermoplastic processing were investigated. The effect of protein material contents on physico – mechanical and biodegradability properties has been evidenced. Keywords: biodegradable plastic materials, collagen hydrolysates, protein material

The objective of this study was to obtain graphene oxide starting from graphite and to covalently functionalize this nanomaterial with Cisplatin. The presence of the drug was pointed out using different methods like FTIR Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Thermogravimetric analysis (TGA), RAMAN Spectroscopy, X-Ray Diffraction and Scanning electron microscopy (SEM). Keyword: Graphene oxide, covalent activation, Cisplatin

The study was conducted on a powdery mixture derived from mechanical processing of plastics recovered from the instrument panels of ELVs, which contain varying amounts of polypropylene (PP), acrylonitrile butadiene styrene (ABS), polycarbonate (PC),cardboard, rubber, and other materials. The mixture was deposited on a metallic belt-type electrode that introduced them into an area of high intensity electric field created by a rotating cylindrical electrode, connected to a high voltage supply. This electrostatic separation method in association with classical waste processing techniques is a viable solution for the ELVs recycling industry. Keywords: plastic waste, electric fields, electrostatic measurements, electrostatic processes, electrostatic separation

The paper presents the results by application of one method to study the behaviour of packaging material in contact with food products, using different type of adhesives and different types of films for the package manufacturing. The presented method is based on primary aromatic amine determination using spectrophotometer analyze. Three different types of adhesives and three types of different films were considered for testing the migration of aromatic amines. The test was made in the same conditions for each product. Results are used for selecting optimum for material and technology in packaging of food and drinks products by multi-layer lamination in flexible approach. Key words: packaging material, adhesives, migration limit, aromatic amines, food products

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. Keywords: biotechnology, protein wastes, cellulose, biopolymer, tannery

The paper presents a study about obtaining materials with prolonged biocidal effect based on styrene-butadiene block-copolymers (SBS) grafted with methacrylic acid (ACM) and coupled with antibiotics from the ampicillin group. The IR spectroscopy and the elemental analysis were used to confirm the structure of SBS block-copolymers grafted with methacrylic acid and of the medical ones. The content of grafted methacrylic acid was about 18.8 % in accordance with the 1,2 enchained butadiene content, proving that the methacrylation polymer-analogous reaction takes place at these pendant vinyl groups of the polybutadiene chain. The concentration of the methacrylic acid-ampicillin pendant group is about 38 % and corresponds to the theoretical calculated one. The antibacterial testing of the synthesized polymers showed that the final reaction product has a relatively high biocidal activity on gram-positive and gram-negative microorganisms. Keywords: styrene-butadiene block-copolymers, methacrylic grafting, polymer with antibiotic effect