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The epoxy resin EPO 99B, known under the name REZOLIN, is one of the main materials used in manufacturing/modeling the axial runner of hydraulic machines. The simplest device of this kind is the inducer employed to reduce the cavitation intensity of the main pump impeller. The geometry is determined from hydrodynamic conditions, is a very complex one and is subjected to dynamic mechanical stress (vibrations). As a result of those conditions the resin must have good mechanical and technological qualities. It was realized at SC Elba SA Timisoara, and is made from a mixture between the resin H9951 and a fortifier. The obtained inducer runners have been tested in air at the Hydraulic Machinery Laboratory of Timisoara Polytechnic University, and supplementary the basic material was tasted to cavitation erosion resistance. As a result, our work takes into considerations both the impeller hydrodynamic performances and the behaviour of the manufacturing material (resin EPO 99 B) to cavitation erosion. Key words: epoxy resin, cavitation erosion of plastic material, inducer runner performances

This paper presents some morphological properties of polyamide 6 thin films obtained by spin-coating method. These properties were investigated by scanning electron microscopy and atomic force microscopy. It results that the thin film thickness is influenced both by rotation speed and solution concentration. Finally, some aspects between morphological and optical properties (structural colours) were considered. Key words: polyamide thin films, spin-coating method, scanning and atomic force microscopy, structural

Poly(betaine)s based on poly(N-vinylimidazole) (PNVI) and poly(4-vinylpyridine) (P4VP), namely poly(carboxybetaine)s with one (PNVIB-1 and P4VPB-1) and two (PNVIB-2 and P4VPB-2) methylene groups between the opposite charges were prepared. Poly(betaine)s represent high dipolar materials with wide spectrum of unique and specific properties. Some of such properties are shown in this paper. Thus, the PNVIB-1 and P4VPB-1 are insoluble in water but the addition of salts promotes their solubility, whereas PNVIB-2 and P4VPB-2 are soluble both water and aqueous solution of salts as well as in methanol. Also, for all the polybetaines one of the most interesting properties in solid state is the formation of homogeneous blends with some inorganic salts in equimolecular amounts, they being a new type of organic-inorganic hybrid materials. Keywords: poly(carboxybetaine)s, anti-polyelectrolyte behaviour, poly(zwitterions), organic-inorganic hybrids

A new type of polyurethane metal-complex was prepared by incorporating the transition metal ions such as copper (II), cobalt (II) and nickel (II), into polyazomethine-urethane-urea, containing functional groups. Polyazomethine-urethane-urea (PAMU) was synthesized from 5,5’-methylene-bissalicylaldehyde (MBS) by reaction with an urethane prepolymer based on polyethylene adipate diol (PEA), hexamethylene diisocyanate (HDI) and ethylene diamine (EDA), in DMF as solvent, using 0.5 wt % dibutyltindilaurate (DBDTL) as catalyst. The polymeric Schiff base was converted to the chelates of the metal salts. This complex was performed by mixing of the polyazomethine-urethane-urea, containing functional groups, with the metal salts in DMF as solvent. The polyurethane metal-complexes were characterized by FT-IR spectroscopy and elemental analysis. The polymer property investigated was their thermal stability which was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The aim of this work is to present a general idea of the various methods of preparation, properties, and applications of metal-containing polyurethanes. Keywords: polyazomethine-urethane-urea, chelate polymers, metal-polymer complex

The applications of membranes and membrane processes in advanced separations from biotechnology have gained lately a great importance determining their inclusion among the top technologies. This paper presents an original variant for preparation of some affinity membranes from acylated polysulphone and brominated polyphenileneoxide, with immobilized starch as affinity ligand for biospecific separations. Keywords: membranes, phase inversion, affinity ultrafiltration , ligand

The aim of this paper is to present a proper methodology for obtaining active mould parts. The originality of the paper consists in the fact that building these active objects starts from some distinctive marks (machine parts) for which there’s no technical documentation. Using reverse engineering procedures (scanning and reconstruction) for polymeric material machine parts and rapid prototyping procedures by material sampling, we will finally obtain both the wanted distinctive mark and its active elements. Keywords: reverse engineering, rapid prototyping, polymeric material, mould

A series of poly(maleic anhydride-alt-vinyl acetate) conjugates with alkylating agents were evaluated regarding antitumoral activity, biodistribution and organotropic effects. The synthesized conjugates exhibits a significant antitumoral activity expressed as ATR (average tumor retention). In addition the obtained macromolecular compounds show a prolonged half-life in sanguine serum and accumulation in tumoral tissue. The last effect is supposed to be enhanced by EPR (enhanced permeation and retention) effect. The analyzed compounds also exhibit some organotropic effects such as the increase of liver, spleen and kidney weight. The LD50 values of the alkylating agents and conjugated ones proved that the coupling reaction decrease the intrinsic toxicity of the alkylating agents. Keywords: poly(maleic anhydride-alt-vinyl acetate), antitumoral activity, EPR effect

New chemically modified polysulphones with both N-phenacyl-4, 4’-bipyridinium bromide and N-alkylacetate-4, 4’-bipyridinium bromide derivatives, have been synthesized by chemical modification reaction of chloromethylated polysulphones with various N-substituted monoquaternary-4, 4’-bipyridinium bromides. The structure of the modified polysulphones was confirmed by elemental analysis and 1H-NMR spectroscopy. Various reaction conditions were checked in view to obtain soluble polymers. Key words: chemically modified polysulphone, chloromethylated polysulphone, N-phenacyl-4, 4’-bipyridinium bromide, N-alkylacetate-4, 4’-bipyridinium bromide, viologen

Composite materials are sometimes harder to machine than metals, because they are anisotropic, not homogenous and their reinforcing fibers are very abrasive. Significant damage to the work piece may be introduced and high wear rates of the tools are experienced while machining. A presentation of the data obtained through experiments and an analysis of the drilling moments when machining composites will be made in this article. Keywords: the polymeric composite materials, cutting, drilling moments

The paper presents the parameters of the ultrasonic welding process of some combinations of materials. These parameters can be divided intro three categories: technological, mechanical and acoustical. A particular attention has to be paid to the technological and acoustical parameters, since they influence the quality of the welds. Keywords: welding horn, energy director, near field, far field, static force