Flowing inert atmosphere

Fig. 1. Cyclic voltammetry of 7% w/w iron phthalocyanine, FePc dispersed on Vulcan XC-72 carbon, after a heat treatment at 280°C in a flowing inert atmosphere. The measurement was conducted with the material in the form a thin porous Teflon bonded coating in 1 M NaOH at 25°. Sweep rate 5 mV/s. (Reproduced with permission from ref. 3. Copyright 1985 Elsevier.)...

Flowing inert atmosphere containing controlled amount of volatile product One method for investigating the influence of product pressure on reaction rate is to measure reaction kinetics by TG studies in flowing atmospheres that contain controlled amounts of the product of interest. This approach is... 

Schleuter and Siggia [69-71] and Frankoski and Siggia [72] used the technique of alkali fusion reaction gas chromatography for the analysis of imide monomers and aromatic poiyimides, polyamides, and poly(amide-imides). Samples are hydrolysed with a molten potassium hydroxide reagent at elevated temperatures in a flowing inert atmosphere ... 

Face-centered cubic-phased Ni(0) with controlled shape (particles [158] and flowers [159]) can be synthesized via thermal decomposition at 400-500°C (Scheme 3.4) of tris(bipyridine)nickel(II) chloride [Ni(2,2 -bipy)3]Cl2-5H20 [158], bis(bipyridine) nickel(II) chloride [Ni(2,2 -bipy)2Cy [158], and [Ni(NH3)JCl2 [159] compounds under flowing inert atmosphere. A careful selection of the precursor, control of heating, and inert gas flow rates leads to different sized metallic particles. 

Another method, namely laser ablation, was first used to synthesize CNTs in 1996 hy Thess et al. [31]. In this method, a graphite target mixed with a Co and Ni catalyst is evaporated hy laser irradiation under flowing inert atmosphere at lower temperature, that is, 1200°C. The carbon products are swept by the flowing gas and deposition occurs on a water-cooled collector. Diameter and size distribution of CNTs can be controlled by adjusting the reaction temperature during the growth procedure and the catalyst composition. 

For the DSC measurements of di-ureasil ormolyte samples, sections have been usuaUy removed from dry films and subjected to thermal analysis under a flowing inert atmosphere between 25 and 300 °C and at a heating rate of 5°C min. Samples are then transferred to aluminium cans. 

Other techniques include oxidative, steam atmosphere (33), and molten salt (34) pyrolyses. In a partial-air atmosphere, mbber pyrolysis is an exothermic reaction. The reaction rate and ratio of pyrolytic filler to ok products are controlled by the oxygen flow rate. Pyrolysis in a steam atmosphere gives a cleaner char with a greater surface area than char pyroly2ed in an inert atmosphere however, the physical properties of the cured compounded mbber are inferior. Because of the greater surface area, this pyrolytic filler could be used as activated carbon, but production costs are prohibitive. Molten salt baths produce pyroly2ed char and ok products from tine chips. The product characteristics and quantities depend on the salt used. Recovery of char from the molten salt is difficult. 

A typical measurement was performed as follows. The feeder was lowered into the crucible and the sample solution (seawater) was allowed to flow under an inert atmosphere with the suction on. A constant current was applied for a predetermined time. When the pre-electrolysis was over, the flow was changed from the sample to the ammonium acetate washing solution, while the deposited metals were maintained under cathodic protection. Ammonium acetate was selected for its low decomposition temperature, and a 0.2 ml 1 1 concentration was used to ensure sufficient conductivity. At this point the feeder tip was raised to the highest position and the usual steps for an electrothermal atomic absorption spectrometry measurement were followed drying for 30 s at 900 C, ashing for 30 s at 700 °C, and atomization for 8 s at 1700 °C, with measurement at 283.3 nm. The baseline increases smoothly with time as a consequence of an upward lift of the crucible caused by thermal expansion of the material. 

The flow of N2 gas through the solution is stopped, but is continued to be passed over the surface of the solution gently so as to maintain an 02 free inert atmosphere in the reaction vessel,... 

The photoacoustic calorimeter of figure 13.6 can be divided into three subsets of instruments converging on the sample cell. The first set is used to initiate the photophysical process in the cell the second allows the detection and measurement of the photoacoustic signal produced the third is used to measure the solution transmittance. A flow line conducts the solution throughout the system. The calorimeter can operate under inert atmosphere conditions, and the temperature variation during an experiment is less than 0.5 K. 

Data for the uncatalyzed polycondensation from STA (simultaneous TGA/DTA) experiments under high-flow inert gas at atmospheric pressure [8] are shown in Figure 2.28. These data also demonstrate the dependency of the overall polycondensation rate on the polymer film thickness. 

Poly(vinyl chloride) was also masticated with neoprene in an inert atmosphere at 145° C for 30 min (60), giving an easily flowing powder of low bulk density. Goto and coworkers (61) blended poly(vinyl chloride), poly(methyl methacrylate) and polystyrene in an open roll after investigating the degradation condition for each component to find the optimum combination of the component. 

The checkers used an inverted funnel connected to a source of dry nitrogen to provide an inert atmosphere for the filtration. The filtration was carried out as completely as possible directly beneath the inverted funnel through which a rapid stream of nitrogen flowed. 

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