Thermal stability Thermogram

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... 

The DSC thermogram of a representative star block showed two TgS corresponding to the PIB (at -67 °C) and PpClSt (at 127 C) segments. The star block showed high thermal stability. The 5% decomposition temperature, Tj, was... 

Figure 4.7 Example of a typical study of a reaction in the isothermal mode (upper thermogram), followed by the study of the thermal stability of the final reaction mass in dynamic mode (lower thermogram).

Figure 10.4 Example of thermograms obtained during flooding of a reaction mass with a cold solvent (top). The thermal stability is checked by a heating ramp after flooding (bottom).

When 8-hydroxyquinoline and derivatives of bis(8-hydroxy-quinoline) react with metal ions, coordination complexes and polymers are formed, respectively, which exhibit improved thermal stability. This paper reviews the reaction of first-row transition metal ions with such ligands and their effect on the stabilization of these organic molecules. For the polymers containing divalent Mn, Co, Ni, Cu, or Zn the decomposition temperature is related to the periodic properties of the metal as well as the composition of the ligand to which the metal is coordinated. Trivalent chromium produces a crosslinked polymer when it reacts with bis(8-hydroxy-5-quinolyl)methane, and the thermogram for this polymer is also reported. 

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... 

Single- and Multiple-Feature Criteria. Suitable criteria or indices of thermal stability should be uniquely and consistently available from the thermogram patterns for any of the materials to be analyzed. The values should not be unduly disturbed by features of the thermogram not related to thermal stability such as early moisture content loss. Criteria for stability may be conveniently divided into two groups, those in which a single feature is used and those in which cumulative data or multiple features are used. One of the difficulties of most single-feature... 

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]. 

Thermograms of the methane and methyl chloride films and a commercial sample of polyethylene are shown in Figure 6. The latter is presented for comparative purposes. The differences between the methane and methyl chloride films can be seen readily from their thermal stabilities. The behavior of the methane film is similar to polyethylene, losing weight rapidly above 300 °C. The methyl chloride film by contrast loses weight slowly above 300°C. and the loss levels off above 550°C. About 81% of the sample is left at 800°C. 

Fig. 78. Effect of copolymerization with methyl acrylate on the thermal stability TVA thermograms for 26/1 (dashed line), and 8/1 (dotted line) copolymers, compared with that for polymethylmethacrylate of comparable molecular weight (full line) [316].

Figures 10.31 and 10.32 show the TGA spectra for the FEP resins, DSC s of which have been shown in Figs. 10.27 and 10.28. A comparison of these figures indicates deterioration in the thermal stability of FEP after incorporation of pigment. Figure 10.33 represents the TGA thermogram for a PTFE (3 l%wt)...

The thermal stability of the proteins was measured by differential scanning raicrocalorimetry (DSC) using a Microcal model VP-DSC calorimeter (Microcal, Inc., Northampton, MA), with data analysis by Origin for DSC software (Microcal). Thermograms were collected for samples containing 50 4g/ml protein at pH 5.0 in SEC buffer. Calorimeter scan rate was 60 °C/h. 

Fig. 3 Thermal stability of FaeA and FaeB. DSC thermograms were acquired as described in the Materials and Methods section...

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