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There were investigated the performances of some UV stabilizers systems in the surface layer (gel coat) of unsaturated polyesthers. The changes in colour and in gloss were determined using accelerated degradation methods as well as natural ageing. The correlation of results allowed the proposal of a degradation model of the polyestheric surface layer under UV radiations action.

This paper proposes the insertion of correction coefficients for the volumes of natural gas measured with mechanical gas meters. These coefficients are based on the annual average values of the atmospheric pressure and temperature, also taking into account the altitude of the measuring point, as they were experimentally established in the laboratories of the Petrol – Gaze University in Ploiesti. Keywords: mechanical meters, correction coefficients, natural gas

The incorporation of functionalized carbon nanotubes in a polymer matrix is expected to greatly enhance the physical and mechanical properties of the polymer due to inherent superior properties of carbon nanotubes (CNTs): high modulus and strength, high thermal stability and enhanced electrical conductivity. Nanocomposite materials based on epoxy polymer matrix and different types of functionalized carbon nanotubes were synthesized. The effect of CNTs on dynamic mechanical properties by DMA, on curing process by DSC and themostability by TGA and DTG were studied. The system based on diglycidylether of bisphenol A (DGEBA) cured with a polyetheramine (D230) and reinforced with amino-functionalized double-wall carbon nanotubes (DWNT-NH2) showed lower Tg values. SEM images reveal an enhance of dispersion if amino-functionalized CNTs are used. Keywords: epoxy, nanotubes, nanocomposites, thermostability, glass transition temperature

Literature relates the membrane modification as a way to obtain affinity membranes having new mechanical and physical-chemical properties, specific to each application. One of the most used technique for the modification of the membrane characteristics consists of grafting the different reactive functions on polymeric chain: -COOH, NH2, -SO3H, -X, -OH etc. This paper offers an original variant for preparation of modified polysulphone by Friedel-Crafts acylation and the obtaining of brominated polyphenileneoxide. Keywords: polysulphone, polyphenileneoxide, reactive functions, acylation, bromination

The paper presents the synthesis and characterisation of a new Mannich polyether polyol with high nitrogen content and thermostable isocyanuric structure. The synthesis was performed by the alkoxylation in the absence of any catalyst of a Mannich base obtained by the reaction of cyanuric acid with a Mannich precursor reagent 1,3-oxazolidine. The Mannich polyol was characterised by 1H NMR and 13C NMR, infrared spectroscopy and by the determination of some usual characteristics such as hydroxyl number, viscosity, amine echivalent, water content. The main application of this polyol is the production of “spray” rigid polyurethane foams with higher thermostability and inherent flame retardancy properties. Keyword: 1,3-oxazolidine; isocyanuric Mannich polyether polyol; rigid polyurethanic foams

Analysing the Maddock and Egan dispersive zones, their thermal homogeneisation effect and their role in dispersing agglomerated particles within the melt, resulted a correlation between the barrier zone slit height, h3 and the length of the barrier zone, L02 assuring the dispersing of the agglomerated particles within the melt. Given the role the Maddock and Egan zones have, based on the obtained relations, their dimensions (h3, B3, L02,j) can be calculated. Keywords: Maddock and Egan, thermal homogeneisation, in dispersing, barrier zone

The effect of organofunctional silane coupling agents on the morpho-structural (XRD) and thermal (TGA) characteristics of the organically modified montmorillonite was examined. The modification of the organosilicates was carried out using organofunctional silane coupling agents in ethanol. The obtained results demonstrate the interaction of the silane-coupling agents with the organosilicate layers. The thermal stability and the basal spacing of the organosilicates increases with silane coupling agent’s concentrations. Using organosilicate modified with functionalized coupling agent PP based nanocomposites with enhanced thermal stability and a more disordered lamellar structure were obtained. Keywords: organically modified montmorillonite, silane coupling agents, polymer nanocomposites

This paper describes the kinetic evolution, in solution, of N-phenylmaleimide - vinyl acetate alternating copolymerization. The rate of consumption for the equimolar composition of the two monomers is described by the empirical equation: Valt=k . [M]1.70[I]0,49. There were formulated hypotheses to explain those dependences. The copolymers obtained were analysed by SEC. It was proved the structure of the alternate copolymer and the fact that high molecular products results . Keywords: N-phenylmaleimide, vinyl acetate, alternate copolymerization, alternate copolymer

Thermoplastics are widely used for engineering application and customer goods. One of the application area is automotive industry. The passengers’ compartment is an example of using high quality materials and advanced design solution in order to achieve aesthetic interiors and performance when safety is the issue. The impact of the passenger’s head with the cockpit module is studied by experimental and numerical simulation. Material models are studied in order to obtain good results and to validate the numerical model for further investigation. Keywords: thermoplastics, material characterization, impact, experiment, numerical simulation

In this paper, a methodology to evaluate the dynamic fracture toughness of polymethyl methacrylate (PMMA) is presented. The proposed methodology is based on a hybrid-numerical formulation and requires the evaluation of the dynamic stress intensity factor along the experimentally measured dynamic crack fronts, and the three-parameter Weibull stress model for brittle fracture. The apparent fracture toughness master curves are determined for Double Cantilever Beam (DCB) specimens of PMMA with different thickness. Keywords: dynamic fracture toughness, polymethyl methacrylate, Weibull master curve