DTGA curve

The TGA results in Figure 10.20 show a mass loss of 5.8 %wt. due to the loss of moisture absorbed. Besides, the DTGA curve shows two weak effects at respectively 200°C and 236°C which were not detected for the reference sample (the degradation onset temperature of the reference sample was about 250°C). 

The differential thermogravimetric analysis (DTGA) curves in Figure 3.2 show that for polyformaldehyde decomposition in an inert atmosphere at 170 C, its maximal rate is achieved at 200 C, while its second maximum is at 209 C. Acetylation of polyformaldehyde enhances its thermal stability the first maximum on the DTGA curves is now at 250 G, while the second is at 285 G. This effect is associated with the fact that polyformaldehyde readily decomposes to monomer because of the presence of polar C-O bonds and OH groups ... 

Figure 3.2 DTGA curves of polyformaldehyde (1) and acetylated polyformaldehyde (2) during decomposition in a nitrogen atmosphere. Source ...

However, the acetylation procedure is less effective for stabilisation of polyformaldehyde against thermal-oxidative degradation in this case the polymer begins to degrade at 150 °C, with maxima on the DTGA curves at 180 C and at about 247 °C. This is associated with the ready oxidation of the terminal acetyl group via a radical mechanism. 

Shown in Fig. 3.14 and 3.15 are example TGA/DTGA curves for two polye-theric PTHF materials with analogous structures. Only the type of diisocyanate differs (MDI or DBDI). The molar proportions is hard segment macrodiol chain extender=4 1 3, giving HS mass fractions in the region of 40%, and isocyanic index I = 100. 

Fig. 3.15 TGA/DTGA curves for a DBDI based PUs (DBDI BG PTHF) [251]...

Fig. 17. TGA and DTGA curves for the thermal decomposition of calcium oxalate (CaC204, H2O) in argon at 20 C/min (3).

Fig. 21. Schematic TGA and DTGA curve for compositional analysis of a rubber vulcan-...

T maximum degradation temperatures determined from the derivatives TGA (DTGA) curves. T melting temperature determined by differential scanning calorimetry (DSC). 

As shown in differential thermogravimetric analysis (DTGA) curves in Figure 1.9(a), nanocellulose shows three peaks at 46.6,275, and 374 °C. The maximum decomposition rate at 275 °C reaches 0.96%/°C, followed by the mild decomposition rate of 0.18%/°C observed at 374 °C. The three broad maximum decomposition rates of PANI are all less than 0.1%/°C, indicating a much slower decomposition rate than that of PANI. 

Figure 1.9 DTGA curves of (a) nanocellulose and PANl, (b) PANI and nanocellulose/PANl composite containing 20% PANI prepared at the concentrations of aqueous nanocellulose suspension of 0.1, 0.5, 1.0, and 2.0%.

Fig. 5.5 TGA diagrams of CNWs from flax a DSC curve and b TGA/DTGA curves. Reproduced from Ref. [56]...

As seen in DTGA curves, the DTGA peaks positioned at 338 °C, which implies the maximum degradation rate of CNWs. A weak and broad shoulder centered at around 250 °C was observed prior to the main peak, resulting from the decomposition of CNWs with sulfate groups [63]. 

TGA analysis suggested a complex decomposition pathway for poly-BF3k derivatives reported in Table 7. The DTGA curves showed that the decomposition process occurred in different steps. 

FIGURE 1 Curves TGA, DTGA, the DTA polyvinyl acetate (1) and copolymer VA with DMB (2) the mass content DMB 40% in air atmosphere. 

The principal applications of TGA/DTGA in polymers are (2) determination of the thermal stability of poljuners, (2) compositional analysis, and (3) identification of pol5miers from their decomposition pattern. Also, TGA curves are used to determine the kinetics of thermal decomposition of poljuners and the kinetics of cure... 

Fig. 17 TGA (solid line) and DTGA (dashed line) curves obtained with poly-BFl in air and nitrogen...

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