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In this study were investigated the thermal and mechanical behavior of some polyurethane ignites by addition with nonreactive flame-retardants. Some flame-retardants, such as the compounds containing halogen, give toxic and corrosive fumes during combustion. To prevent these problems, non-halogenated flame-retardants, such as phosphorus-containing compounds, are materials of choice. The polyurethane elastomers were prepared using dibenzyldiisocyanate (DBDI) as isocyanate, poly(ethylene-adipate)diol (PEA) as polyol, diethylehe glycol (DEG), hexanediol (HD) or 1,4-butanediol (BD) as chain extenders, and different amounts of tris(1,3-dichloro-propyl-phosphat) (TDP). In some cases, to be improved the flame resistance was used small amounts of antimony trioxide (Sb2O3), which act as a “synergistic effect”. The polyurethane ignites were characterized by thermogravimetric analysis (TGA), elemental analysis and stress-strain measurements which were performed on a TIRAtest 2161 apparatus (Germany), equipped with a 100N cell and an extension rate of 10 mm/min. The hardness measurements were effectuated on disc with an apparatus standardized in grade Shore A (oSh A).

Synthesis of orto- and para-aminobenzoic groups grafted on copolymers is described. The method is applied, extended and optimised for gel-type styrene-divinylbenzene copolymers (S-DVB) with „5` and „7` degree of crosslinking.

Some photosensitive structurally different polyamides were obtained using as starting monomers various dicarboxylic acids and 2’-(cinnamoyloxy)ethyl-3,5-diaminobenzoate. Their synthesis is based on the Yamazaki-Higashi procedure. The characterization of the prepared polyamides was accomplished by spectroscopic and thermal measurements.

Multitude of methods for the synthesis of nanoparticles express interest and importance of this field. In the present study, are addressed the aspects of obtaining nanoparticles by milling, in order to be used at nanostructured coatings in asphalt. Materials used for obtaining nanoparticles were powdery volcanic tuff with 0.4-1.6 mm grain and calcium carbonate. Stearic acid, sodium lauryl ether sulphate, a mixture of fatty acid imidazoline, a block copolymer polyethylene oxide- polipropilenoxid -polyethylene oxide and polyethylene glycol were used as additives. For grinding of inorganic particles was used a laboratory planetary mill Fritsch Pulverisette 6, equipped with a stainless steel grinding bowl. Grinding dry powdered volcanic tuff in the presence of additives influences particle size distribution. Wet milling of powdered volcanic tuff in the presence of ROT favours getting a bimodal distribution and decreasing the average particle size. Keywords: nanoparticles, grinding, additives, particle size distribution

Due to physical properties of the composite materials based on resin – textile fibres cover, in the present different utilisation areas such as: terestrial, aerian and naval transport, civil and industrial engineering, medical tehnique, food industry, sportive articles etc. This paper present ssthe determination of the water’s absorption in composites resin – flax, resin – cotton, resin – hemp.

Photochromic properties of copolyethers and copolyesters based on bisphenol-A 4,4’-dihydroxydiphenyl, 4, 4’-dihydroxy-azobenzene and 3,3-bis (chloromethyl) oxetane both embedded in a polymer matrix [polymethyl metha crylate (PMMA), polyxinil alchol (PVA)] and the pure state, deposed on quartz disks or as powder, have been studied. The photocromic effects have been studied by means of electronic absorption spectra in visible range. This effect is reversible. A general characteristic of the compounds studied in this paper is that the azobenzene groups belonging to the polymer chain are aligned along the polymer chain structure. The nature of the thermally stimulated discharge current for polyether and polyester samples in the temperature range from room temperature to above glass-rubber transition temperature of the studied compounds, with crystallinity degree of about 0.45, is analyzed. Processing the experimental data according to the Gauss’ function (1) has lead to a good agreement between them and the dipolar polarization model that uses the Langevin’s function, L(b) (2). The thermally stimulated current spectrum of the studied compounds shows two peaks at a temperature about 330 and 3444 K. The a peak is at temperature ( 323 –333)K and r peak at (340-355) K. The disorientation of the main chain dipoles (diazo groups) and the realizing of the trapped electrons are probably responsible for the a peak. The changes in the r peak is caused by carries of charges generated in the polar groups of the polymer chain by the thermochromic effect of the diazobenzen groups.

By exposure to the environment of polymer wastes, the disintegration and degradation processes take place by simultaneous and concurrent mechanisms, as photodegradation, hydrolisys, thermooxidation and biodegradation. The latter may be described as a complex process taking place in several steps. In a first step of the biodegradation process, the polymer with low molecular mass suffer a hydrolisys reaction enzymatically catalyzed, resulting in a mixture of oligomers and intermediates with low molecular mass and different chemical structures. The next step is preceded by microorganisms invasion, transforming the carbon and the hydrogen of polymers and respective intermediates into CO2 and H2O. In the study there are presented some reaction and initiation mechanisms of the biodegradation processes of some synthetic polymers susceptible to biodegradation.

In this paper a relaxation model for polymeric materials is presented.

The copolymerization of octamethylcyclotetrasiloxane and methylhydrogensiloxane oligomers was carried out using a styrene-divinylbenzene copolymer with sulphonic groups as catalyst (VIONIT CS-34C). The conversion versus time function was studied at different temperatures. It was found a first order reaction towards monomers.