نتایج جستجو برای: Thermal stability
تعداد نتایج: 498679 فیلتر نتایج به سال:
in this project, some new polyaspartimides, (pas)s, have been synthesized form michael addition reaction between new synthetic bismaleimide (bmi) and some aromatic diamines. a characteristic property of this polyaspartimides is a pendent carboxylic group, which introduced to these polymers from new bismaleimide. bismaleimides (bmi) is one of the interesting compounds, which can be self-polymeri...
heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...
magnesium hydroxide nanostructures as an effective flame retardant were synthesized by a facile and rapid microwave reaction. the effect of different surfactants such as cationic, anionic and polymeric on the morphology of magnesium hydroxide nanostructures was investigated. nanostructures were characterized by x-ray diffraction (xrd), scanning electron microscopy (sem) and fourier transform in...
in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...
aacel9a [β-1,4-endoglucanase, (e.c:3.2.1.4)], was immobilized onto glutaraldehyde activated chitosan macrosphere by covalent attachment. the properties of the immobilized aacel9a were investigated by determining the optimum ph and optimum temperature for activity, thermal stability, and kinetic parameters. the immobilization process shifted the enzyme’s optimum temperature from 65 °c for the fr...
mg(oh)2 nanoparticles were synthesized by a rapid microwave reaction. the effect of sodium dodecyl sulfonate (sds as anionic surfactant) and cetyl tri-methyl ammonium bromide (ctab as cationic surfactant) on the morphology of magnesium hydroxide nanostructures was investigated. multi wall carbon nano tubes was organo-modified for better dispersion in cellulose acetate matrix. the influence of m...
the nanostructured anatase tio2 with high thermal stability was prepared by polymeric sol-gel method without any additives. the particle size distribution of polymeric titania sol was determined by dynamic light scattering (dls). then properties of obtained titania were investigated by tg-dta, xrd, fesem and tem. also, the decolorization capability of resultant anatase was evaluated using methy...
in this article cuo/water nanofluid was synthesized by using polyvinylpyrolidone (pvp) as the dispersant. thenanofluid stability period and the heat transfer enhancement were determinedby measuring the thermal conductivities. to study the nano-fluid stability, zeta (ζ) potential, and absorbency were measured under different ph values and pvp surfactant concentrations; also thermal conductivity...
this paper is the first multi-scale characterization of the fluidize-dried gum extracted from the fresh fruits of the plant abelmoschus esculentus. it describes the physical, thermal, sorptional and functional properties of this natural gum. elemental analysis, scanning electron microscopy (sem), particle size analysis, x-ray powder diffraction (xprd), thermo-gravimetric analysis (tga), differe...
hemicellulose of southern yellow pine wood spices was extracted by pressurized hot water at three different temperatures: 140°c, 155°c and 170°c. compounding with pp (polypropylene) was performed by extrusion after preparing wood flour and sieving to determine its mesh size. the ratio of wood to polymer was 50:50 based on oven-dry weight of wood flour. all extraction treatments and control samp...
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