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In this work we study the carbonization resulting from an intumescence phenomenon of the fire-retardant formulation: ethylene terpolymer-ammonium polyphosphate/pentaerythritol. Characterisation of the intumescent coating is carried out using infrared spectroscopy and MAS-NMR of the solid state. The study shows the formation of organic phosphocarbonaceous esters, which limits depolymerisation or the...
The pulse method was used to measure the thermal diffusivities of a polygranular nuclear-grade graphite and of several standard coals of the CERCHAR-SBN minibank, in the range 20-500°C. Below 300°C, the diffusivities of the coals decrease with increasing temperature (from 0.11 ± 0.02 mm 2 s -1 to 0.07 ± 0.02 mm 2 s -1 , depending on the material), a reversible...
The reactivity of a C 60 + 15% C 70 fullerene mixture in various gases was studied using thermal analysis (TG/DTA) and infrared spectroscopic techniques. The thermal behavior of fullerenes was found to be complex and strongly dependent on the heating rate, overlapping of different phenomena taking place. Comparison with the behavior of a number of carbon materials showed...
We report on the possible synthesis of the theoretically predicted β-phase of carbon nitride (C 3 N 4 ) by shock compression of sodium dicyanamide mixed with sodium azide and carbon tetra-iodide. Shock-compression experiments were performed on starting precursor blended with ~95 wt.% Cu powder, statically pressed in steel capsules. The capsules were impacted under conditions of constant...
Pitch-based activated carbon fibers (ACFs) were modified with nitric acid and sodium hydroxide. Their physicochemical properties were investigated in terms of N 2 adsorption, mass titration, FTIR and metal adsorption. The specific surface area of the ACFs decreased after oxidation with 1 M nitric acid, but the total acidity increased three times compared to the untreated ACFs, resulting in...
In this second part, the kinetics of the ozonation process of a char prepared from cherry stones (CS) is investigated. The char was obtained by heat treatment of CS at 600 o C for 2 h in nitrogen. The effects of reaction time, partial pressure of ozone, and mass transport phenomena on the formation of oxygen complexes are studied. The surface chemistry of the samples was examined by FT-IR...
Ultraviolet radiation-based stabilization routes were explored to produce carbon fibers from melt-processible PAN-based copolymers. An acrylonitrile/methyl acrylate (AN/MA) copolymer was melt-spun into fibers that were crosslinked using UV radiation. The fibers could then be stabilized by oxidative heat treatment, and subsequently carbonized. Physical and mechanical testing was performed to determine...
The reaction of silica-supported [60]fullerene with vaporous nonylamine at 150 o C produces a mixture of addition products. Quantum chemical calculations, at the B3LYP/STO-3G level of theory, support that the addition reaction most likely takes place across the 6,6 bonds of C 60 pyracyclene units (and not across the 5,6 bonds). Numerous peaks were found in high-performance liquid...
The preferential sites for lithium doping in hydrogen-rich amorphous carbon materials are investigated by considering, as a model, a large polycyclic aromatic hydrocarbon (PAH): hexa-peri-hexabenzocoronene. Quantum-chemical calculations are carried out with B3LYP/6-31G * density functional theory to study the lowest energy configurations of the PAH doped with two lithium atoms. Infrared and...
The thermostabilization of lignin fibers used as precursors for carbon fibers was studied at temperatures up to 340°C at various heating rates in the presence of air. The glass transition temperature (T g ) of the thermally treated lignin varied inversely with hydrogen content and was found to be independent of heating rate or oxidation temperature. A continuous heating transformation (CHT)...
A new synthesis route for the formation of boron nitride (BN) nanocapsules by means of a substitution process using single wall carbon nanotubes as templates, with yields of >95% is presented. It is also shown that these BN nanocapsules can act as ideal reference samples for the determination of the relative sp 2 to sp 3 configuration in BN species, a value that is crucial for the...
A low-cost route for producing PAN-based carbon fibers is being developed. The approach involves forming polyacrylonitrile terpolymers that can be melt-spun into fibers. The fibers are then stabilized and carbonized to yield carbon fibers. Melt-processibility, however, precludes direct thermal stabilization of these polymeric fibers. Therefore, a precursor terpolymer containing acryloyl benzophenone...
Multi-walled carbon nanotubes after modified by using a H 2 SO 4 and HNO 3 mixture solution were added to cement matrix composites. The mechanical properties of the newly formulated composites were analyzed, and the results show that the treated nanotubes can improve the flexural strength, compressive strength, and failure strain of cement matrix composites. The porosity and...
The role of charcoal like components (also referred to as char) in soil organic matter reactivity has become increasingly evident. Recently we have demonstrated the role of such material in bauxite. Sodium hydroxide is used at elevated temperatures to separate aluminium hydroxide from ferric oxide in bauxite in the Bayer process and charcoal like material may interfere with the precipitation of aluminium...
Gd@C 82 and Gd 2 @C 80 were selectively reduced and extracted from the raw soot in a high yield by using Al–Ni alloy in toluene/tetrahydrofuran (THF). By tuning the ratio of toluene and THF, Gd 2 @C 80 with purity higher than 95% was isolated directly from the raw soot without high performance liquid chromatography (HPLC) purification. Furthermore, we found...
The search for materials aimed at energy storage has prompted the synthesis of new materials which were obtained by pyrolysis of aromatic precursors under controlled conditions for the production of carbon based structurally disordered networks aimed at hydrogen or lithium storage. Obviously these materials consist of fully insoluble mixtures of different molecular species which escape the traditional...
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