Polyamide silica

Magne.sia-celitc or magne.sia-kieselguhr Ccllulo,se-silica gel Polyamide-silica gel Polyamide-kie.selguhr Polyamide-cellulose Polyamide-gl ass... 

Q, S, and E) Fractoflow, Chromolith Merck (Germany) Hollow fibers, monolithic rods Polyamide, silica lEX, RP... 

Thermogravimetric analyses of various polymer—silica composites including PDMS-sihca [61], polyamide-silica [33,34], polyimide-silica [15,38,47], polybenzoxazole-silica [16,17], polybenzobisthiazole-sihca [16,17] and PDMS -silica-titania [62] have been reported, in all cases indicating that the incorporation of silica raises the temperature of thermo oxidative degradation of the polymer. A possible mechanism for the improvements in degradation temperature could be due to silica inactivating the terminal OH groups... 

Sarwar MI, Zulfiqar S, Ahmad Z (2008) Polyamide-silica nanocomposites mechanical, morphological and theimomechanical investigations. Polym Int 57(2) 292-296... 

Mixed sorbent layers have been used by various workers to increase resolution of certain samples compared to that obtained on the separate phases. Binary layers that have been reported include silica gel-alumina, kieselguhr-alumina, alumina-calcium sulfate, magnesia-lcieselguhr, cellulose-silica gel, polyamide-silica gel, polyamide-kieselguhr, polyamide-cellulose, and polyamide-glass powder. The properties of these mixed layers are somewhere between those of the two separate phases but are impossible to predict or explain with certainty. Applications of mixed layers are contained in the older standard TLC texts and reviews. 

H, and Si NMR spectroscopy has been used to study polyamide-silica) hybrids. NMR data have also been reported for (dimethylam-monio)methyl bis(methanecarboxylatothiolate)silicate, ( C, [Pr 2NH2]... 

Fig. 5. Solid-phase supports made of synthetic resins. Figs 1 and 2 The nucleoside linkages used on the early polystyrene popcorn supports (3,4). Fig. 3. The nucleoside linkage used on a polyamide based resin (5). Fig. 4 The structure of a polyamide/silica gel composite developed for continuous-flow synthesis (8) Fig. 5. The structure of a PEG-polystyrene grafted copolymer, tentacle support (25). The mean mol wt of die PEG side chain is 3000 daltons. Fig 6 The nucleoside linkage used on the recently introduced highly crosslinked polystyrene support (27).

A rigid polyamide/silica gel composite (Fig. 5) was eventually developed for continuous-flow synthesis, which produced quite good results with phosphotriester synthesis chemistry. This support produced quite good results, but it was not widely used despite its commercial availability. 

The reinforcing filler usually takes the form of fibres but particles (for example glass spheres) are also used. A wide range of amorphous and crystalline materials can be used as reinforcing fibres. These include glass, carbon, boron, and silica. In recent years, fibres have been produced from synthetic polymers-for example, Kevlar fibres (from aromatic polyamides) and PET fibres. The stress-strain behaviour of some typical fibres is shown in Fig. 3.2. 

Hydrophilic liquids can also cause stabilization and amplification of fluorescence Thus, Dunphy et al employed water or ethanol vapor to intensify the emissions of their chromatograms after treatment with 2, 7 dichlorofluorescein [260] Some groups of workers have pointed out that the layer matenal itself can affect the yield of fluorescent energy [261 —263] Thus, polyamide and cellulose layers were employed m addition to silica gel ones [245] The fluorescence yield was generally increased by a factor of 5 to 10 [264], but the increase can reach 100-fold [234, 265]... 

Note The reagent can be employed on silica gel, kieselguhr, polyamide, RP, CN, NH2 and cellulose layers. 

Note The layers on which the reagent can be employed include silica gel, cellulose and polyamide. 

Note Aldoses other than glucose can also be used e.g. arabinose [1], xylose [2, 3, 7] or ribose [4]. The background color is least on cellulose layers when cellulose acetate, aluminium oxide 150, silica gel, RP, NH2 or polyamide layers are employed the background is a more or less intense ochre. The detection limit of carboxylic acids on cellulose layers is ca. 0.5 pg substance per chromatogram zone. 

Note The reagent can be employed on silica gel, alumina, polyamide and cellulose layers. In the case of the latter it is to be recommended that the solutions be diluted 1+3 with methanol. The detection limit is reported to be 0.1 to 0.5 pg per chromatogram zone [5]. 

Note The reagent can be employed on silica gel, kieselguhr, RP and, with lower sensitivity of detection, on cellulose layers. The color differentiation is probably greater on cellulose layers [1]. A dark blue background is produced on polyamide layers. 

Note Silica gel, kieselguhr and polyamide layers can be used as stationary phases. Not all acids are stained on RP layers. Amino layers yield a pale blue background. The detection limits are in the pg range for carboxylic acids [1], thioglycolic and dithioglycolic acids [2] and for antithyroid pharmaceuticals [4] they are about 5 ng per chromatogram zone for sterols and steryl esters [6]. 

The reagent can be employed on cellulose, silica gel and polyamide layers [11] kieselguhr, RP and Si 50 000 layers are also suitable. 

Note The dipping solution can also be sprayed on. The detection of the aromatic acids is best performed on cellulose layers, if ammonia-containing mobile phases have been employed. The reagent can also be employed on silica gel, aluminium oxide, RP 18 and polyamide layers. 

The reagent, which can also be employed to impregnate the layer before chromatography, is best suited for silica gel layers [4] it can, however, also be employed on aluminium oxide, kieselguhr. Si 50000, cellulose and polyamide layers [4]. 

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