IGC

Several properties of the filler are important to the compounder (279). Properties that are frequentiy reported by fumed sihca manufacturers include the acidity of the filler, nitrogen adsorption, oil absorption, and particle size distribution (280,281). The adsorption techniques provide a measure of the surface area of the filler, whereas oil absorption is an indication of the stmcture of the filler (282). Measurement of the sdanol concentration is critical, and some techniques that are commonly used in the industry to estimate this parameter are the methyl red absorption and methanol wettabihty (273,274,277) tests. Other techniques include various spectroscopies, such as diffuse reflectance infrared spectroscopy (drift), inverse gas chromatography (igc), photoacoustic ir, nmr, Raman, and surface forces apparatus (277,283—290). 

Vinogradov Institute of Geochemistry SB RAS Favorsky Street F, Irkutsk, 664033 Russia, E-mail petrov igc.irk.ru... 

Siberian Branch of Russian Academy of Sciences Favorsky St.,lA, Irkutsk 664033, Russia, E-mail lsuvor igc.irk.ru... 

Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, Russia, 664033, Irkutsk, Favorskiy st. 1 A, pavpla igc.irk.ru... 

Russian Academy of Sciences, Siberian Branch, Institute of Geochemistry Favorsky St. 1 A, 664033 Irkutsk, Russia, obel igc.irk.ru Irkutsk State University, Institute of petroleum coal chemical synthesis Lermontov St. 128, 664033 Irkutsk, Russia, sskornikova mail.ru... 

Animal Maximum average /igC /igC 95 percentile figC Maximum figC Annual areraqe figc 95 percentile figC ... 

GROMOS http //igc.ethz.ch/gromos/gromos.html... 

GROMOS A general-purpose molecular dynamics computer simulation package for the study of biomolecules http //igc.ethz.ch/gromos/weicome.htmi GROMACS (GROningen MAchine for Chemical Simulations) http //rugmdO. chem. rug.ni/ gmx/... 

The simplest mode of IGC is the infinite dilution mode , effected when the adsorbing species is present at very low concentration in a non-adsorbing carrier gas. Under such conditions, the adsorption may be assumed to be sub-monolayer, and if one assumes in addition that the surface is energetically homogeneous with respect to the adsorption (often an acceptable assumption for dispersion-force-only adsorbates), the isotherm will be linear (Henry s Law), i.e. the amount adsorbed will be linearly dependent on the partial saturation of the gas. The proportionality factor is the adsorption equilibrium constant, which is the ratio of the volume of gas adsorbed per unit area of solid to its relative saturation in the carrier. The quantity measured experimentally is the relative retention volume, Vn, for a gas sample injected into the column. It is the volume of carrier gas required to completely elute the sample, relative to the amount required to elute a non-adsorbing probe, i.e. 

Fig. 17. A schematic of the alkane line obtained by inverse gas chromatography (IGC) measurements. The relative retention volume of carrier gas required to elute a series of alkane probe gases is plotted against the molar area of the probe times the. square root of its surface tension. The slope of the plot is yielding the dispersion component of the surface energy of...

Fig. 18. Yield strengths in three-point bend tests of highly filled composites of polyfvinyl butyral) and silica particles treated with methylsilane and octylsilane coupling agents to varying degrees of surface coverage vs. work of adhesion measured independently using IGC. Redrawn from ref. [90].

The technique of IGC may be employed to obtain acid-base information, as suggested by Schultz and Lavielle [99], by using acid and base probe gases on a solid for which the alkane line has already been obtained. If acid-base interaction is involved in the adsorption, the retention volume should be greater than that corresponding to the dispersion force interaction alone, which should be the same as that of the equivalent alkane , i.e. the hypothetical alkane for which the value... 

Fig. 19. Inlerfacial shear strengths of various fiber/matrix composites as a function of the work of adhesion as determined by IGC. 1, glass fiber-poly (ethylene) 2, carbon fiber-epoxy B 3, carbon fiber-epoxy A and 4, carbon fiber-PEEK. Redrawn from ref. [102].

The adsorption of gas onto a solid surface can also be used to estimate surface energy. Both inverse gas chromatography (IGC) and isotherm measurement using the BET method [19] have been used. Further discussion and detailed references are given by Lucic et al. [20] who compare the application of IGC, BET and contact angle methods for characterising the surface energies of stearate-coated calcium carbonate fillers. 

In table 5.2, we list the maximal numbers of possible cycle states CotI Ct for OT and T rules, respectively, the total number of possible distinct state transition topologies (including trees), fd iGc), and the number of equivalence classes Q, for small N in T 2. The number of possible state transition topologies is evidently much smaller than the number of distinct connected topologies (= , [cvet79]). Note that the sets Cot and Ct are the same for even-N, while for odd-N, Cot is the same as Cot for N — 1) (since... 

Analog den Pyridinen, Chinolinen usw. werden auch die entsprechenden N-Alkyl-Derivate im Heteroaromaten-Kern hydriert. So erhalt man z. B. aus 3-Hydroxy-4-me-thyl-pyridinium-methylsulfat u. a. 3-Hydroxy-1 - methyl-pip eridin (20%igc Schwefelsau-re/Blei-Kathode geteilte Zelle)2. 

Monkos K, Turczynski B. 1999. A comparative study on viscosity of human, bovine and pig IgC immunoglobulins in aqueous solutions. International Journal of... 

---