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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

The paper presents a methodology devoted to statistical analysis of welding characteristic process parameters in high frequency for Polyvinyl Chloride. The experimental values for technological parameters assure a high stability during the control processes in production as well as a high quality of joint welding. Key words: high frequency, welding, polymers, process

The characterization study of the molecular structure for some Mannich type condensates, obtained by the replacement of the acid catalysis, is presented. The characterization of the condensation products was conducted by IR and MNR spectroscopy. For the amino-salicylic-formaldehide condensate, the possibility to be used as an activating agent on a standard structure of butadienstyrenic rubber reticulated by a classic vulcanization system based on sulphur and sulphenamide was demonstrated. Keywords: Mannich condensates, structural analysis, vulcanization activating agent

In this paper the authors propose a new method to determine the properties of a composite material made from two different components: fiber glass cloth and resin. On the separation surface between the two materials it is assumed that the continuity conditions concerning the tensors of stresses and strains between these two components are totally satisfied. The constitutive equations were determined for each material as functions of these components with respect to a local system of reference. Medium stresses and strains were defined in order to establish the properties of the material as a whole. Considering the interdependence existing at the level of those properties the constitutive equations of the composite have been found. Mathematical expressions for elastic modulus and Poisson’s ratio have been also determined. A loading with forces applied on a longitudinal as well on a perpendicular direction face to the fibers direction of the composite is considered. We find out that the elastic properties along the fibers of the composite are closer to the properties of the reinforcing fibers and the elastic properties perpendicular to the fibers of the composite are closer to the matrix properties. Keywords: composite, elastic properties, constitutive equations

Two new polymeric materials were prepared by coating of polyurethane (PU) with a collagen (COL) gel and a mixture of collagen-elastin (COL/EL). The bioactivated polymeric materials were examined by scanning electron microscopy (SEM) for pore morphology. They were also comparatively assayed for porosity, mechanical properties and biodegradability in the presence of bacterial collagenase. In vitro biocompatibility studies were performed in a primary culture of human dermal fibroblasts using spectrophotometric and light microscopy methods. These new polymeric materials showed good tensile strength, biodegradability and a high in vitro biocompatibility. They can be used in the field of medical devices where such physical and biological features are necessary. Key words: polyurethane, natural polymers, collagen, elastin, biocompatibility, biodegradability

Ultraviolet and heat-curable polyurethane acrylate prepolymers were synthesized from 4,4’-diphenyl methane diisocyanate, polyethylene adipate diol, polyhexamethylene carbonate diol, polycaprolactone diol and 1,6- hexamethylene diamine , acrylic acid. Effects of nature of the soft segments on the physical properties were investigated. It was found that the thermal stability increased from polycarbonate diol to polyester diol. Tensile modulus and strength decreased for polyurethane acrylate based poly (ethylene adipate) diol. DSC scans show that all of the model polymers exhibit thermal transitions including a glass transition below –35oC. These soft elastic segment structures, in addition to the physical and chemical cross-linked nature of hard segment, provide enough crosslink sites to have elastomeric behaviour. Keywords: polyurethane acrylate, cross-linked, mechanical properties, thermal behaviour

Present paper refers to the possibility of obtaining nanocomposites through microemulsion copolymerization of butylacrylate (BuA) with vinyltriethoxysilane (VTES), in the absence/presence of some layered silicates. The maximal reaction rates of the BuA/VTES systems, with/without layered silicates, were evaluated through gravimetric technique. The products were characterized by FTIR spectroscopy, TGA and ESEM microscopy. Keywords: microemulsion, layered silicates, sol-gel process