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In this paper the behavior at elevated temperatures (thermal oxidation) of some new copolymers exhibiting photochromic properties has been studied. These copolymers were prepared by chemical grafting of some azoic dyes on the support-polymers chains. The thermal oxidation has been studied by DTA, TG and DTG in the range of 22°C - 500°C for both support-copolymers and grafted photochromic polymers. The experimental data suggest that, upon heating, various oxidation processes occurs which are accompanied by slight increasing of the sample weight (at moderate temperatures), and oxidative decomposition processes accompanied by more or less intense decreasing in sample weight (at higher temperatures, over 300°C). The temperature values corresponding to these transformations seem to be related to both the polymer and grafted substituent structures. Thus, the halogen containing substituents induced a significant increasing in stability, especially in the case of chlorine containing ones. The imide structure of these substituents seems to induce a higher stability as compared to amic one. Keywords: thermal oxidation, photochromic, azoic dyes

It was studied the possibility of using as texture agents in the formulation of some epoxy-polyesteric powder dyes of a cellulosic derivative - encoded AT1 and of an acrylic resin - encoded AT2. From the analysis of the influence of the texture agent AT1 and AT2 respectively, on three epoxy-polyesteric powder dyes (pure white powder, graphite grey and signal black, according to RAL Design Classic Card K7, RAL Farben, Germany), it was established that their main characteristics are not influenced by the presence in the composition of the texture agent. In order to realize the requested textured aspect of the coatings realiyed with epoxy-polyesteric powder dyes in which fornulation there were introduced these texture agents, their concentration must be correlated with the ligand content. Keywords: texture agents, coatings, powder dyes

The paperwork presents the principal constituent equations used on study of mincing rubber waste without insertion. These equations permit a study of mincing process on analytical ground, without being necessary, in some cases, to conduct experimental research. For verifying these equations, it is presented here an experimental part too, based on which it can be done a verification of constituent equations. Keywords: constituent equations, mincing rubber waste

This paper presents the effect of some rosemary and sage extracts on the thermal stabilization of low-density polyethylene (LDPE). IR and UV spectra of these extracts indicates that the major substances are carnosic acid, carnosol and epirosmanol. Chemiluminescence (CL) resulting from the exothermic termination reaction of peroxi radicals was used for the characterization of effectiveness of these extracts for protection of LDPE. Keywords: rosemary, sage, extraction, antioxidant, chemiluminescence

This paper describes the kinetic evolution, in solution, of styrene-N-phenylmaleimide alternating copolymerization. The rate of consumption for the echimolecular composition of the two monomers is shown by the empirical equation VP = kp[M]1.17[I]0.4; there were formulated hypothesys to explain those dependences. The copolymers obtained were analysed by IR and GPC; it was proved the structure of the alternant copolymer and the fact that it results high molecular products. Keywords: styrene-N-phenylmaleimide, alternating copolymerization,alternant copolymer

The main aim of this paper is to study the thermal stability of some aromatic copolyethers containing a tetramethylenic spacer. The polymers were synthesized using a phase transfer catalysis technique, starting from 1,4’-dichlorobutane and various bisphenols: 4,4’-dihidroxyazobenzene, 4,4’-dihidroxy-diphenyl, bisphenol A and 2,7-dihidroxynaphthalene. It was studied the correlation between structure - thermostability - degradation mechanism. There were used thermodynamic, thermogravimetric methods, derivative thermogravimetry and differential thermal analysis for the evaluation of the kinetic characteristics and for establishing the correlation between activation energies - the conversion rate. The thermal stability is determined by the azo moieties within the main chain. The thermostability of the copolymer is improved by raising the content of the co-monomer with the highest thermostability. The degradation mechanism derives from successive reactions, with a nucleation complex process. Keywords: thermal stability, liquid crystalline copolyether, azobenzene, thermal degradation mechanis

A series of bismaleimides with amide or ester linkages were prepared by condensation-dehydrochlorination reaction of 3(4)- a-chlorosuccinimidobenzoic acid chloride with diamine or diols. The monomers were characterized by thermal stability using dynamic thermogravimetric analysis (TEA) and DSC study. Keywords: bismaleimides, amide, thermogravimetric analysis

In this study a series of urethane prepolymers based on diisocyanates (diphenylmethane diisocyanate – MDI, toluene diisocyanate – TDI), castor-oil and filler from bronze aluminum and bitumen in methylene chloride as solvent was synthesized for corrosive protection of equipments utilized in nonferrous ore industry. The polymers were tested to work, for a period, after which the materials were analyzed to see how they resisted in corrosive medium. In ore industry, the corrosion of equipment utilized is both an electrochemical and physical (abrasion) process. In the form of a liquid spray coating, the polyurethane elastomer is especially useful for protecting industrial ore equipments, adding years of service to surfaces that would otherwise suffer from wear and corrosion. The polyurethane coatings have been characterized by means of TEM, TGA, 1H-NMR and IR spectroscopy, and stress-strain measurements. The hardness measurements were effected on disc with a standardized apparatus in grade Shore A (oSh A). Keywords: polyurethane elastomer, coating, corrosive protection

The delivery pharmacokinetics of the codeine, which was entrapped in some polymeric matrices, was studied. As matrices, the methyl methacrylate homopolymer and methyl methacrylate copolymers with different percentage of 2, 3 epoxypropyl methacrylate were used. The release profile is correlated with the nature and obtaining manner of the macromolecular structures with and without the presence of a continuous electromagnetic field respectively. Keywords: crosslinked, functionalised copolymers, codeine, drug release, release rate

The present paper deal with a less known subject from the unconventional technologies namely the fluid flow through a working zone situated between the tool and workpiece electrodes. One take into account the possible types of flow, one establish the mathematical model of the flow and based on this model one determine the process parameters and their influence on the fluid behavior during the process. One present some experimental results for the EDMUS process which confirm the concordance between the theoretical model and the experimental values of the rheological parameters. Key words: electrical discharge, shear stress, shear speed, dielectric liquid