Thermostable ILs

Thermostable ILs Polymer nanocomposites are often prepared from thermoplastics processed at high temperature or from thermosets with high polymerization temperatures [31, 32], In order to get thermal stability, the commonly used surfactants combine organic cations containing nitrogen such as pyridinium and imidazo-lium ILs [33]. Other chemical compounds, such as pyrrolidinium [34] and... 

In conclusion, it was demonstrated that the use of ILs as intercalating agents of layered silicates was developed by using quaternary alkylammonium. However, the use of these ILs is limited by their low thermal stability, which implies to focus on more thermostable ILs based on pyridinium, imidazolium, and phosphonium cations. Nevertheless, does the addition of such highly thermostable IL surfactants improve the dispersion of nanofillers in polymer matrices as well as the final properties of the resulting nanocomposites ... 

The organic-inorganic hybrid materials have shown significant increases in properties compared to the conventional composites or neat polymers. The degree of dispersion of nanofiUers in a polymer matrix and the processing method play a key role on the final properties of the materials. Key objectives of researches are to design nanocomposites with enhanced properties at low filler contents. Different modified clays have been used in view of these objectives [31,52], There are reports on the use of ammonium-treated layered silicates [52,53], whereas the use of thermostable ILs such as pyridinium, imidazolium, or phosphonium is poorly reported. However, their combinations with poly(styrene) (PS) [54], PE [55], PP [56], poly(vinylidene fluoride) (PVDF) [57], and PET matrices [58] have been reported in the literature. 

PVDF nanocomposites based on ammonium-, pyridinium-, imidazolium-, or phosphonium-modified MMT have been prepared by melt intercalation [57,64-73]. The influence of the modified clays on the morphologies and their consequence on the physical properties have been investigated. XRD and TEM analyses evidence different morphologies as a function of the nature of the surfactant. An exfoliated structure is obtained with ammonium-, pyridinium-, and imidazolium-treated MMT, while phosphonium IL-modified MMT leads to a partially exfoliated morphology. The mechanical properties of nanocomposites are higher than the neat PVDF. However, the influence of thermostable ILs on mechanical properties is limited. In fact, the storage modulus of the neat PVDF and the PVDF nanocomposites remains the same whatever be the nature of the IL intercalant. Nevertheless, the elongation at break increases (-1-175%) with 5wt.% of pyridinium-treated MMT compared to h-200% of strain at break obtained for ammonium-modified MMT. Recently,... 

Figure 3.7. Large volume injection of 100 (il of a mixture of n-alkanes of wide volatility using the PTV injector in the cold split solvent elimination mode. The vaporizing chamber was thermostated at 0°C, split flow 250 ml/min with the split vent closed after 2.5 min. For splitless transfer the vaporizing chamber was heated at 4°C/s to 325°C with the puige flow started after 1.5 min. (From ref. [68] Wiley-VCH).

A mixture of o-aminoaryl ketone (1,2 mmol), a-methylene ketone (2,2 mmol), 2 mL of [Hbim] [BF4] (IL) in 0.5 mL of methanol was sonicated in an atmosphere of argon at ambient conditions in a thermostated (25 1 °C) ultrasonic cleaning bath for a stipulated time (10-35 min for varying entries). After completion of the reaction (as indicated by TLC), the reaction mixture was poured into crushed ice and stirred for about 1 h. The solid separated was filtered through a sintered funnel under suction, washed with ice cold water (20 mL) and then purified by silica gel column chromatography (10% ethyl acetate in hexane) to afford the pure quinoline derivative 3 (65-93% yield). Each of the products was characterized by analytical and spectral studies. 

New ILs and coating methods are being developed for high efficiency and high thermostability GC columns. Chiral GC stationary phases with high thermo-stability and broad enantiomeric selectivity are needed. One area that will continue to grow in imp>ortance is the use of ILs as absorbents in solid-phase extractions (SPE) and solid-phase micro-extractions (SPME). It is likely that ILs will fill the role of a polar absorbent for these techniques [Han Armstrong, 2007]. 

As salts the most natural application of ILs is of course as electrolytes. In fact ILs are known for their high conductivity (lO" to lO S cm-i), high electrochemical stability (4-5.7 V) and thermostability (up to 300 °C). This set of properties together with the fact that most of ILs are nonvolatile and nonflammable, has driven their application as electrolytes for different electrochemical devices, such as dye synthesized solar cells, double layer capacitors, fuel cells, electrochemical windows and of course lithium secondary batteries. (Byrne et al., 2005 Fernicola et al., 2006 Galinski et al., 2006 Lu et al., 2002 Stephan, 2006)... 

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