TGA thermograms

In order for maleimide/vinyl ether photoinitiator free photopolymerization to be useful, it is important that the cured films have good thermal/UV stability. Since there are no small molecule photoinitiators added to the uncured mixture initially, there is no residual small molecule photo initiator present in the final crosslinked film. This accounts for the enhanced UV stability we have observed for cured maleimide/vinyl ether films. In addition, TGA thermograms of photocured films of the MPBM/CHVE mixture (Figure 8) exhibit excellent thermal stability, with decomposition occurring at higher temperatures than for a simple UV cured HDDA film with 3 weight percent DMAP photoinitiator. (Such thermal stability would be... 

A TGA thermogram of dobutamine hydrochloride, run simultaneously with the DTA, shows (figure 1) no weight loss until 233°C which results from decomposition. 

Figure 1. TGA thermograms of condensation products of PEI with Bu2SnClg ( . ) 0gSnClg...

Figure 2. TGA thermograms of products from dipropyltin dichloride (-----), tripropyltin dichloride ( ), dioctyltin dichloride (A/A/J, dibutyltin dichloride (-), diphenyltin dichloride (----------), and cotton itself (- -) at a heating rate of 20°C/min in air...

Figure 2. TGA thermograms of oligomers 3a-d obtained in air with a heating rate of 10°C/min.

Thermal Analyzer equipped with a differential calorimetric cell. TGA thermograms were obtained on a DuPont 1090 Thermal Analyzer. Elemental analyses were performed by Galbraith Laboratories, Knoxville, TN. 

In TGA, a sensitive balance is used to follow the weight change of a polymer as a function of time, atmosphere, or temperature. Figure 13.3 shows a typical TGA thermogram for a... 

The endotherm at 192 °C is due to the fi-d crystalline phase change, and the exotherm at 276 °C is due to the violent decomposition of HMX. Thermal pre-ignition and ignition temperatures of explosive substances can be obtained from DTA and TGA thermograms. 

One synthesis was repeated to access the reproducability. Further, for many of the synthesis two apparently different textured materials are produced. We also analyzed these two different textured materials for one sample. One texture is a white powder and the other is a transparent film. TGA thermograms, FT-IR and elemental analysis results are the same for all of these products. For instance, for the two textures of material and a replicate of this same reaction, the percentages of Mg are 10.52% (powder), 10.34 (film) and 10.34 (duplicate). 

Figure 3.2 TGA thermogram (N2-flow, 150ml/min, heating rate lOK/min) ofKieselgel 60. 3.2 Rehydration and rehydroxylation...

The hyperbranched polymers are carbon-rich macromolecules and show excellent thermal stabilities. The thermal properties of the hb-PAs are described below as an example. Their thermal stabilities were evaluated by TGA. Figure 3 shows TGA thermograms of some hb-PAs and Table 4 lists their thermal analysis data. The hb-FAs were thermally very stable for instance, hb-P66 lost merely 5% of its weight at a temperature as high as 595 °C. All the polymers, except for hb-F(44-Vl) and hb-F(59-Vl), carbonized in > 50% yields on pyrolysis at 800 °C, with hb-P(45-V) graphitized in a yield as high as 86% (Table 4, no. 3). The thermal stabilities of the hb-PAs are similar to that of Unear pol-yarylenes such as PPP but different from those of Unear polyacetylenes such as PH and PPA. The dramatic difference in the thermal stability is mainly due to the structural difference PPP is composed of thermally stable aromatic rings (Td 550 °C) [108-112], whereas PPA and PH are comprised of labile polyene chains, which start to decompose at temperatures as low as 220 and 150 °C, respectively [113]. The excellent thermal stabilities of the hb-FAs... 

Figure 2.13. (a) TGA thermograms of pristine polymer as well as nanocomposites containing varying amounts of nanotubes and (b) degradation temperatures of side and main chain components of the polymer in the composites. Reproduced from reference 52 with permission from American Chemical Society. 

Figure 12.16. TGA thermograms of pure natural rubber (NR) and of NR composites, under a nitrogen atmosphere (a) and derivative mass loss rates (b).

Figure 2. Typical pressure TGA thermograms of Wyoming coal heated at 50 C/min and 500 psig H2 ...

The TGA thermograms of a-chitin obtained from different sources are shown in Fig. 2.13B. The thermal degradation of chitin occurs between 300 and 460 °C. The TGA thermograms for all samples showed a single major degradation step and the differences between chitin of different origins are relatively small (chitin from krill shows the highest thermal stability) [23]. 

FIGURE 2.13 The TGA thermograms of a-chitin from (A) shrimp and (B) different sources (a) crab, (b) squid, (c) krill, and (d) shrimp. 

DSC thermograms were recorded on either a DuPont 900 or a Stanton Redcroft STA 785 + CPC 706 instrument with a heating rate of 20°C/min. TGA thermograms were determined with the Stanton Redcroft instrument. Thermal transitions were also studied using a Linkam... 

Figure 5. TGA Thermograms Comparing the Decomposition of Various Grades of Pyrites with permission from reference 19. Copyright 1984 VGB.

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