Wax Analyses

Figure 13.22 shows the resolution of the surfactants Tween 80 and SPAN. The high resolution obtained will even allow the individual unreacted ethylene oxide oligomers to be monitored. Figure 13.23 details the resolution of many species in both new and aged cooking oil. Perhaps the most unique high resolution low molecular weight SEC separation we have been able to obtain is shown in Fig. 13.24. Using 1,2,4-trichlorobenzene as the mobile phase at 145°C with a six column 500-A set in series, we were able to resolve Cg, C, Cy, Cg, C9, Cio, and so on hydrocarbons, a separation by size of only a methylene group. Individual ethylene groups were at least partially resolved out to Cjg. This type of separation should be ideal for complex wax analysis.

Figure 1. (a) TEM micrograph of [Pd/lJeou with the size distribution diagram (b) WAXS analysis, comparing the rdf of colloid [Pd/... 

Monquero, P.A., P.J. Christoffoleti, M.D. Osuna, R. De Prado Amian, A.J. Matas, and A. Heredia. (2004). Absorption, translocation, and metabolism of 14C-glyphosate and leaf surface and wax analysis. 4th International Weed Science Congress, p. 60, S15MT08P00. 

Henon, G., Recseg, K. and Kovari, K. (2001) Wax analysis of vegetable oils using liquid chromatography on a double absorbent layer of silica gel and silver nitrate-impregnated silica gel. J. Amer. Oil Chem. Soc., 78(4), 401 110. 

Figure 7.15 shows pictorial elements of another model which has been pro-posed. This model was examined by WAXS analysis. An assumption was made that the composite consists of rubber matrix, filler particle, and boundary layer, which diffract waves without interfering with each other. The total radial density difference function, atotai, was calculated from the following equation ... 

Figure 8 WAXS analysis of octanethiol-stabilized Pt colloid (solid line experimental data dotted line cuboctahedral model). Reproduced with permission from the Royal Society of Chemistry.

XRD is a rather simple and widely used technique for the characterization of a layered-clay dispersion in a polymer matrix. WAXS analysis was used to quantify the height between adjacent silicate platelets, and subsequently to prove the widening of this distance as the matrix polymer intercalates between the galleries. Changes in the value of 20 reflect changes in the... 

Another interesting approach to wax analysis, simultaneous pyrolysis-alkylation-gas chromatography, was also reported by Challinor, who used tetramethyl ammonium hydroxide (TMAH) to alkylate acids of different waxes, making them more volatile. He concluded that the different waxes may be readily distinguished by the distribution of fatty acid methyl esters and fatty alcohols. 

Notes n.d. not determined. Amorphous according to WAXS analysis. Semi-crystalline according to WAXS analysis. 

The good dispersion of CNTs in the rubber matrix leads to enhancement of most of the properties of the rubber matrix. The SIC of NR filled with CNT (2 phr) was identified by WAXS analysis and is shown in Figure 22.4. 

The art of filler dispersion in polymer matrix is easily determined by X-ray analysis especially WAXS analysis. The intensity and position of X-ray diffraction peaks reveals the exact idea regarding the morphological structure of polymer nanocomposites. Figure 22.11 compares reduced graphite oxide dispersions in NR matrix by different processes such as milling and solution casting methods. 

WAXS analysis of nanoeomposite layered structure was carried out with a DRON-2 X-ray Diffractometer with Cu-Ka radiation. Diffraction patterns were collected in reflectionmode geometry from 2° to 1O°20. 

Figure 1. WAXS analysis for Cloisite 20A (1) and PP-MAPP-Cloisite 20A (2)...

As was shown in Section 9.2.2, the crystalline form of iPP can be correlated to isotactic block length. Based on this, the samples prepared using both MAO and borate activation (Table 9.2) should mainly crystallize in the y-form. To study the presence of the different crystalline forms in these MAO- and borate-activated low-crystalline polypropylene samples, WAXS analysis was performed as shown in Figure 9.15. Both series A and B display WAXS peaks at = 9.3°, characteristic for the presence of the a-modification, and at = 10°, characteristic for the presence of the y-modification, pointing out that lamellae will crystallize in a mixed a/y-form. 

FIGURE 9.16 Ratios of the a- and y-forms (y/a) in polymers prepared with 9a, determined by WAXS analysis, show that the y-modification is preferred in borate-activated samples (open circles) MAO-activated samples (filled circles) show both modifications in comparable amounts (dotted line indicates y/a =1). 

The WAXS analysis (Figure 11.3) supports the conclusions based on SEM observations (Figure 11.2) regarding the MFC structure of the compression molded plates. This is in very good agreement with other results on this t5q)e of composites based on blends comprising various polymers [21-37,40-50]. 

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