Gelation tests

TABLE 26.1 Results of Gelation Test of Ionic Liquids by Gelators 1 and 2 at 25°C... 

Similar gelation tests were also used with m-xylylene diisocyanate and with hexamethylene diisocyanate [146]. In these tests the order of strength of the catalysts was found to be different from when tolylene diisocyanate was used. Table 12 lists the results of some catalyst screening tests with the three different diisocyanates. 

An extensive review of the use of various gelation tests (G /G" crossover, independence of tan with respect to frequency, infinite viscosity and infinite normal stress, gel filtration and DSC theoretical gel conversion) is given by Halley et al. (1994) for unfilled epoxy-resin... 

Results of gelation test of 68 and 69 toward 26 solvents are summarized in Table 2.11, where solvents up to cyclohexane are arranged in dielectric constant... 

Table 2.11 Gelation test of 68 and 69 and minimum gel concentration necessary for gelation ...

Gelation test temperature for 68 and 69 are 25°C and 20°C, respectively, e is dielectric constant. Other values indicate minimum gel concentrations in g dm (gelator/organic fluid). 

Results of gelation tests are summarized in Table 2.12. The fluids to be gelled range from protic solvents to aprotic ones, from polar solvents to nonpolar ones, and from mineral oils to edible ones. It is obvious that both 80 and 81 are excellent organogelators whose gelation abilities are comparable to those of 68 and 69. For example, the amount of 80 necessary to gel one liter of acetonitrile, N,N-dimethylformamide, ethanol, ethyl acetate, tetrachloromethane, toluene and hexane are 5 g, 10 g, 33 g, 8 g, 23 g, 12 g and 6 g, respectively. This means that one molecule of 80 interacts with about 1800 molecules of acetonitrile, 600 molecules of A,A -dimethylformamide, 200 molecules of ethanol, 600 molecules of ethyl... 

In the same connection, the gelation test of a [60]fullerene-appended cholesterol gelator, (S)-39, was performed in 28 solvents. (S)-39 could only gelate dichloromethane at 25 °C at above the concentration of 16.2 mM, whereas the inverted epimer (R)-39 was inactive in all solvents tested [61] (Scheme 15). CD spectroscopy studies indicated that the [60]fullerene moiety in (S)-39 is chirally oriented in the gel state. The effect of zinc porphyrin/[60]fullerene interaction was investigated by adding Zn TPP into the gel of (S)-39. Interestingly, the addition of Zn TPP disrupted the gel, which is in contrast to the behavior of 38-n in the presence of fullerene. 

Table 3 Gelation test and Tgei values of 29/polynecleotide complexes [54]...

Table 4 Gelation Test for 26a-d in DMSO-water mixtures ...

Table 2 lists the results of the gelation test for compounds 16-19 as gelation agents. 

Table 2 Gelation test and minimum gelation concentration (g dm (gelation agent/solvent) for compounds 16-19 against various solvents at 25°C.

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