## 3 Results and Discussion  
### Thermal Properties  
Figure 4 shows TGA and DTG curves for samples of reducing binders cured at 80 \({}^{\circ}\)C for 24, 72, and 144 h.  
The temperature characteristics of the binder samples are presented in Table 1. As the curing time increases, the heat resistance of the samples increases, and the decomposition temperature increases from 191 to 237 \({}^{\circ}\)C. The maximum decomposition temperature for all three samples is almost the same and is about 378 \({}^{\circ}\)C, which is typical for epoxy resins based on FGE and bismaleimides [8]. The DTG curves for compositions 1 and 2 (Figure 4) show a slight broadened mass loss peak at 178 \({}^{\circ}\)C, which may be caused by the evaporation of FGE remaining in the mixture. In the case of a fully cured composition, this peak is not observed. The ash residue for all three compositions is approximately the same and is about 20%. The sample aged for 24 h showed a slightly faster rate of decomposition compared to the samples that had a longer aging time. Apparently, this effect is associated with the formation of a looser polymer network and with the incompleteness of the reaction of epoxy groups, since the residual FGE peak on the DTG curve for this sample is more  
Figure 4: TGA (**a**) and DTG (**b**) curves of binder samples cured at 80 \({}^{\circ}\)C.  
Figure 3: Scheme of scanning samples of carbon plastics.  
intense. The content of dynamic DA-adducts (DA-adducts) in this sample may be reduced, since the DA-reaction is a rather slow process.  
The thermal characteristics of the binder and the reversible nature of DA-bonds were analyzed by DSC. So, on the curves of the first heating of all samples (Figure 5), there are two clear endothermic peaks. The peak at a lower temperature (72, 92, and 106 \({}^{\circ}\)C for samples 1, 2, and 3, respectively) may be due to the melting of DA-adducts and oligoepoxides [29]. The peak at 72-106 \({}^{\circ}\)C refers to the melting of DA-adducts and oligoepoxides. Samples with different curing times contain oligoepoxy fragments with different molecular weights. The longer the curing time of the sample, the higher the molecular weight of the polymer, which is explained by a shift in the melting temperature to higher temperatures. This behavior is typical of both conventional epoxy resins [30], and for resins with dynamic DA-adducts [31]. An increase in this temperature is most likely due to an increase in the content of bicyclic adducts formed during the Diels-Alder reaction (with an increase in the duration of exposure at 80 \({}^{\circ}\)C, the proportion of DA-adducts also increases), as well as an increase in the molecular weight of oligoepoxides. The broadened peak at \(\sim\)120 \({}^{\circ}\)C can be attributed to the reverse Diels-Alder reaction. As a result of the DA-reaction, as a rule, two types of isomers are formed: kinetic (endo) and thermodynamic (exo). The first type usually has a lower temperature of the reverse DA-reaction [8; 32]. On the curves of the second heating, there are no signals indicating the splitting of dynamic DA-crosslinks, which indicates the completeness of the rDA-reaction. The curves of the second heating also show a transition at 47 \({}^{\circ}\)C, which corresponds to the vitrification of oligoepoxy fragments.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Curing Time** & **Td5v\({}^{\circ}\)C** & **Td10v\({}^{\circ}\)C** & **Tdmax\({}^{\circ}\)C** & **Residue (wt\%)** \\ \hline
24 & 191 & 249 & 377 & 21 \\
72 & 212 & 274 & 382 & 17 \\
144 & 237 & 289 & 375 & 22 \\ \hline \end{tabular}
\end{table}
Table 1: Thermal properties of binder samples.  
Figure 5: DSC curves of binder samples with self-healing effect (solid line—first heating, dashed line—second heating).