Search results for "Chemical engineering"

Preparation and Recycling of Plasticized PLA

2010

Poly(lacticacid)(PLA)hasbeengainingarisinginterestoverthe last years as a biodegradable and environmental-friendly substitute of traditional non-biodegradable poly-mers.Several ways exist to synthesize PLA, however, poly-merization through lactide formation is the most used onindustrial scale, allowing to obtain optimum results interms of mechanical and thermal properties.

From Single Molecules to Nanoscopically Structured Functional Materials

2006

AbstractThe synthesis of MS2 (M = Mo, W) onion-like nanoparticles by means of a high temperature MOCVD process starting from W(CO)6 and elemental sulfur is reported. The reaction can also be carried out in two steps where the intermediate amorphous WS2 nanoparticles formed through the high temperature reaction of tungsten and sulfur in the initial phase of the reaction are isolated and converted in a separate annealing step to onion-type WS2 nanoparticles. Based on a study of the temperature dependence of the reaction a set of conditions could be derived where onion-like structures were formed in a one-step reaction. Onion-like structures obtained in the single-step process were filled, whe…

Electrochemical Syntheses Involving Carbon Dioxide

1990

The recent developments of electrosynthetic processes involving carbon dioxide are reviewed. Both processes involving carbon dioxide alone and electrocarboxylations are taken under consideration. The first of these two fields, mainly projected towards the production of basic chemicals such as methanol or carbon monoxide, is at present at a stage of fundamental research. Some interesting developments have recently appeared in the literature, concerning the use of electrode materials, or of transition metal complexes with particular catalytic activity. Electrocarboxylations are at a stage of more applicative development: some processes have reached the stage of pilot plant, and other have int…

Preparation and Characterization of Tungsten Chalcogenide Photocatalysts

1997

Tungsten chalcogenides powders have been prepared by sulfidation of WO3 with gaseous H2S. Different mixed WS2/WO3 systems have been obtained by varying the amount of initial WO3 powder, the time, o...

Simple New Method for the Preparation of La(IO<sub>3</sub>)<sub>3</sub> Nanoparticles

2020

We present a cost- and time-efficient method for the controlled preparation of single phase La(IO3)3 nanoparticles via a simple soft-chemical route which takes a matter of hours, thereby providing an alternative to the common hydrothermal method which takes days. Nanoparticles of pure α-La(IO3)3 and pure δ-La(IO3)3 were synthesised via the new method depending on the source of iodate ions, thereby demonstrating the versatility of the synthesis route. The crystal structure, nanoparticle size-dispersal and chemical composition were characterised via angle- and energy-dispersive powder X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectrosco…

Explosion limits in hydrogen sulfide/air mixtures Granice wybuchowo�ci mieszanin siarkowodoru z powietrzem

2015

Self-lubricating epoxide composites Kompozyty epoksydowe o właściwościach samosmarujących

2015

A com. epoxy resin was modified by addn. of aliph. polyamine, graphite, a poly-α-olefin oil and phosphate fire retardant, cured at 130°C and studied for friction coeff. in contact with steel, heat resistance and mech. strength. The addn. of graphite resulted in a decrease in the resin hardness, impact strength and friction coeff.

Osmotic membranes from polystyrene-grafted cellulose films

1966

Refractive Indices and Deviations in Refractive Indices of Trifluoromethanesulfonate-Based Ionic Liquids in Water

2011

Refractive indices were determined for four different ionic liquid + water binary systems, from (288.15 to 338.15) K, and covering the entire composition range. The four ionic liquids used were 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 3-butyl-1-ethylimidazolium trifluoromethanesulfonate, 3-butyl-1-methylimidazolium trifluoromethanesulfonate, and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, all of them being completely miscible in water. From the experimental data, deviations in refractive indices, defined on a volume fraction basis, have been calculated and fitted to an extended version of the Redlich–Kister equation. The behavior of the deviations in refractive in…

Three independent channel nanohybrids as fluorescent probes

2015

A properly designed pyrene-capped CdSe/ZnS nanohybrid can act as a three-channel fluorescent sensor due to the independent emission of the pyrene monomer and excimer as well as that of the nanoparticle. As proof of principle, it was tested for a simple and rapid quantification of TNT in the presence of interferents of the same chemical family.