Low temperature weight loss

It is interesting that similar low-temperature weight loss peaks on the DTG curves were also observed for lamellar silicates templated by CTMA+, but the overall shape of the DTG curves was somewhat different [22]. It is not fully clear why these lamellar materials exhibited surfactant decomposition at such low temperatures. This behavior may be related to either properties of their silicate surface or the structural changes in their framework upon heat treatment, or both of these factors, which would promote the Hoffmann elimination at lower temperature [22]. The second of these possible factors may be related to the stress in... 

In Figure 5, the low temperature weight loss rates for several heat-up runs are shown as functions of the extent of weight loss. The range of operating conditions includes l5°-35°F/min temperature rise rates and 20-500 psig pressures. In all cases, the low temperature rate can be... 

Figure 5. Low temperature weight loss of rich shale (heat-up...

In the case of the rich shale, the low temperature weight loss, on the average, is 25.0% and (as are all kinetic data) is based on thermobalance data rather than on chemical analysis. There was no way to identify the components in this 25% from the data taken. 

The randomness of the extrapolated values of about 25%, regardless of temperature, makes it safe to assume that no portion of that 25% is carbon dioxide. Of the other volatile components, 25% of the 28% in the original feed may constitute the low temperature kerogen, leaving 3%. This value is supported by the results of runs in which the shale was at temperatures high enough to achieve full low temperature weight loss (900°-1000°F), but inadequate to go any further. In these runs, the final OVC was 3.3-3.4%. 

In conclusion, we have developed a new and effective method for the purification of SWNTs and MWNTs. The method involves acid washing followed by the high-temperature hydrogen treatment repeated twice. Excellent SWNTs containing little or no amoqihous carbon and metal panicles are obtained by this means, as verified by microscopy, XRD, and spectroscopic techniques. Equally importantly. Ihermogravinietric measurements of MWNTs and SWNTs show that the low-temperature weight loss due to amorphous carbon is eliminated after hydrogen treatment. In the case of laser SWNTs, the oxidation temperature is substantially increased after purification. 

TGA-MS results on the five coals are summarized in Figure 4. The low-temperature weight loss is caused by water and very light organic components. The reason for a 25 C spread between the high temperature maximum of Loveridge over the River King coal is not clear. Both show... 

Table 6.4 Examples of polymers that undergo an initial low-temperature weight loss during a TGA experiment...

Figure 15. A typical thermogravimetric analysis (TGA) trace of a polymer resist that has been spin-coated and NOT prebaked. The small weight loss at low temperature is due to solvent evaporation and the high temperature weight loss is due to thermal decomposition.

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