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The actual tendencies of the European market of metallic component parts for auto vehicles impose the utilization of materials that lead to the increase of the products reliability and their framing into the matrix cost-quality imposed by the big European producers [4, 9, 11, 14]. The covering of the quaternary alloys based on copper with polyester is inscribed among the technological procedures that aim at the improvement of the performances of the metallic parts of the auto vehicles with a view to reducing the percentage of out of operation and decreasing the maintenance and service expenses, having as final purpose the increase of the competitiveness on an European market being in a strong competition. The present work spotlights the positive influence of the covering of the quaternary alloys CuNiAlSi with polyester impregnated with 10% graphite on the main mechanical characteristics, especially of the wearing resistance that has a direct effect on the increase of the functioning time in the total life cycle of the product. Keywords: polyester graphite quaternary alloys

There were studied six variants of type suspension gels with 1.5% propiconazole nitrate, with various ointment bases: 4% hydroxypropyl cellulose (HPC-H), polyethylene glycol modified base and hydrated cetylic alcohol base, using as wetting agent and permeation enhancer glycerol as well as propylene glycol. The aim of this research is the physico-chemical characterization of gels: aspect, pH, homogeneity, rheological behaviour, viscosity and antifungal activity. The formulas based on HPC-H 4% have a plastic behaviour and an increased yield value; the formula sbased on modified PEG are rheopectic type, having a higher degree of thixotropy generated by propylene glycol. The formulae on hydrated cetylic alcohol base have a thixotrope behaviour (the formula including glycerol as wetting agent) and respectively thixotrope – antithixotrope behaviour (the formula including propylene glycol). The values of viscosity are higher in case of gel formulas having propylene glycol as wetting agent. Propiconazole nitrate has a good antifungal activity against clinical isolates of Candida spp., including strains resistant to other antifungal agents. All tested propiconazole nitrate gels have similar activity against Candida spp. Keywords: propiconazole nitate, gels, rheological behaviour, antifungal activity

The paper presents the results of a combined numerical and experimental study for validation of a new three-dimensional specialized finite element, used for modelling the behaviour of laminated composite materials, reinforced with fibers. First, the stress and strain state in a circular plate loaded with an uniformly distributed force and fixed on the contour is evaluated using the proposed finite element. Two types of laminated composites are considered, in order to test the behaviour of the proposed element and the models conceived for calculus of laminated composites having different structures. To validate the new element, calculations were made also using the finite element code ANSYS-11. In the second part, the results of an experimental study on the behavior of plates made of the considered laminated composites are presented and compared with the previous numerical ones. The good agreement between the obtained data showed that the new proposed element is adequate for modelling the bending behaviour of fiber reinforced multilayer composite materials. Keywords:specialized finite element, laminated, composite, fibres, validation

The influences of the concentration of the Pekoflam DPN 1 (active flame retardant reagent), of the cure temperature, of the neutralization efficiency and of the samples final washing after the flame retardant treatment have been studied. By using the analysis of variances there has been proved that all studied factors have significative influences on the length of the carbonization area, on the rate of spread of the flame and on the weight increasing after the flame retardant treatment. Keywords: efficiency, flame retardant reagent, pad-dry-cure technology

The debates study the influence of the molecular structures for polymers welding and establish the conditions when is possible to obtain a welding joint of these and a transition area near welding with properties which ensure good usage. The testing of aptitude of materials for high frequency (HF) welding, were done with Polyvinyl Chloride (PVC) foils with textile insertion and Malivat materials, defining in an experimental way, the optimum process parameters which ensure a good resistance breaking for welding. Key words: polymer, structure, welding ability

Gypsum/ poly(butyl acrylate) composites have been prepared based on natural gypsum and the monomer butyl acrylate by means of gamma irradiation. The conversion of polymerization was followed up with respect to the irradiation dose using thermogravimetric analyzer (TGA). The data show that yield of polymerization increases with increasing the irradiation dose. A yield of about 98% was achieved by exposure of the samples to a dose of 5 kGy. A thermomechanical analyzer (TMA) was used to locate the range of the glass transition temperatures (Tg) using the mode with alternative variable force; the mode with constant force was used to determine the Tg of the pure polymer and the composite prepared at the same irradiation dose. Also differential scanning calorimeter (DSC) was used to ensure the location of the glass transition temperatures. Keywords: Gypsum; polymer composites; butyl acrylate; polymerization; radiation

Three types of polyhedral oligomeric silsesquioxane (POSS) compounds were used to synthesize nanocomposites based on urethane dimethacrylate (UDMA). An advanced characterization of POSS compounds was done by X-Ray Photoelectron Spectroscopy (XPS) for chemical structure, X-Ray Diffraction (XRD) for crystalline phase and Differential Scanning Calorimetry (DSC) for thermal transitions. The POSS compounds generally influence the thermostability of UDMA-based nanocomposites acting both as a comonomer and reinforcing agent. Keywords: polyhedral oligomeric silsesquioxanes, XPS, XRD, DSC, nanocomposites, TGA

The study presents experimental data regarding the curing reactions of some epoxy systems consisting of diglycidyl ethers of bisphenol A and different amine hardeners at room temperature and at microwaves. The curing reaction of the system composed of an epoxy resin (ROPOXID P 401) and 4,4’-diamino-diphenylmethane (HT 972) was studied by differential scanning calorimetry (DSC) and FT-IR spectroscopy. The degree of conversion obtained using FT-IR method is very close to that obtained using calorimetric method. Keywords: epoxy, amine, microwaves, kinetic

Two types of aromatic-aliphatic polyimides have been synthesized: polyaddition polyimides, from the Michael reaction between 4,4’-diaminodibenzylbismaleimide and ethylenediol (diethyleneglycol respectively) and solution polycondensation polyimides, from the reaction of 5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexenyl-1,2-dicarboxylic acid anhydride (epiclon) with 4,4’-diaminodibenzyl [1,4-bis(p-amino phenoxy)benzene respectively]. All monomers and polymers were characterized by conventional methods, and the physical properties of the polymers, including solubility, thermal, optical, electrical or mechanical properties were discussed. Keywords: bismaleimides, Michael reaction, epiclon, aliphatic polyimides

The paper presents the multidisciplinary studies dedicated to the minimization of the residual stresses in an Acrylonitrile-Butadiene-Styrene part. The first stage of the study consists of an experimental research employed to measure the physical characteristics of the polymeric material. The next stage is a simulation of the moulding process for a plate-wise specimen made of the material previously tested, being interested by the values of the residual stresses. The next stage is the experimental research of the residual stresses by the use of the hole-drilling method applied on the previously simulated plate-wise specimen. The results of the two studies are close one to the other and the conclusion regarding the material and the parameters employed for the simulation are used for the next study dedicated to the simulation of the moulding process for a complex part. Several studies were performed in order to find the best parameters of the moulding process which lead to a minimum level of the residual stresses. Other parts made of the same material may be also simulated in order to minimize the residual stresses. We conclude considering that a high degree of confidence regarding the results of the numerical model may be achieved only if the results of experimental studies are employed. Keywords: polymeric part, residual stress, experiment, numerical model, applications