## 3 Results and Discussion
Hence, the first signal observed on the DSC curve is exothermic as a result of various reactions occurring simultaneously [38], but it should be noted that the decomposition is initially endothermic. To confirm the mechanism of copolymer decomposition, FTIR analysis of the emitted volatile degradation products was performed. Based on the 3D FTIR spectrum (Figure 3) and the spectra extracted at maximum degradation temperatures (Figure 4A), it can be concluded that the depolymerization occurs at the beginning of poly(GMA-_co_-1,4 DMB) microsphere decay and is followed by isomerization in the gas phase. The FTIR spectrum of gases gathered at 269 \({}^{\circ}\)C reveals the following bands: bands at 3059 cm\({}^{-1}\) associated with vibrations of the methylene group in the oxirane ring [39]; bands at 1737 cm\({}^{-1}\) from the vibrations of the C=O group in esters [40]; bands at 1650 cm\({}^{-1}\) associated with vibrations of the C=C bond of the methacrylate group; bands at 1158 cm\({}^{-1}\) related to vibrations of the C-O-C group in esters; bands at 939 cm\({}^{-1}\) derived from vibrations of the =CH\({}_{2}\) group; bands at 842 cm\({}^{-1}\) due to vibrations of the oxirane ring [41]. These bands are characteristic of GMA monomer [42] and their presence testifies that depolymerization takes place at the beginning of the decomposition. Furthermore, the FTIR spectrum of gaseous degradation products released at 269 \({}^{\circ}\)C exhibits bands at 2814, 2782 and 1890 cm\({}^{-1}\) that are characteristic of acrolein, which is a product of ester bond breakdown \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Sample** & **T\%** & **T\%** & **T\%** & **T\({}_{\textbf{max1}}\)** & **\(\Delta\)m\({}_{\textbf{1}}\)** & **T\({}_{\textbf{max2}}\)** & **\(\Delta\)m\({}_{\textbf{2}}\)** & **T\({}_{\textbf{max3}}\)** & **\(\Delta\)m\({}_{\textbf{3}}\)** \\  & (\({}^{\circ}\)**C**) & (\({}^{\circ}\)**C**) & (\({}^{\circ}\)**C**) & (\%) & (\({}^{\circ}\)**C**) & (\%) & (\%) & (\({}^{\circ}\)**C**) & **(\%)** \\ \hline poly(GMA-co-TRIM) & 238 & 333 & 251 & 39.4 & 375 & 49.3 & 519 & 9.6 \\ \hline poly(GMA-co-TRIM)-SH & 292 & 365 & - & - & 353 & 89.2 & 531 & 9.5 \\ \hline poly(GMA-co-1,4 DMB) & 254 & 346 & 269 & 33.8 & 388 & 49.9 & 556 & 11.2 \\ \hline poly(GMA-co-1,4 DMB)-SH & 276 & 346 & - & - & 355 & 83.9 & 479 & 16.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: TG and DTG data for the prepared microspheres. Figure 2: TG **(A)**, DTG **(B)** and DSC **(C)** curves of poly(GMA-_co_-1,4 DMB) and poly(GMA-_co_-TRIM) copolymers obtained under non-oxidative conditions. of gaseous GMA and subsequent isomerization [16]. Figure 5 shows FTIR spectra of the gaseous products of copolymer decomposition at 269 \({}^{\circ}\)C, along with the reference spectra of GMA monomers and acrolein obtained from the NIST database [42; 43]. Moreover, from the spectrum recorded at 269 \({}^{\circ}\)C, it is visible that the emission of carbon dioxide (2360 and 670 cm\({}^{-1}\)), carbon monoxide (2180 cm\({}^{-1}\)) and water (3600-3500 cm\({}^{-1}\)) also take places in the first stage of pyrolysis [40]. These inorganic species were formed as a result of dehydration and decarboxylation of the radical intermediate pyrolysis products [44]. To confirm the decomposition course of poly(GMA-\(co\)-1,4 DMB), the material was heated to 265, 360 and 540 \({}^{\circ}\)C, respectively, in a helium atmosphere, and FTIR/ATR spectra of the preheated copolymers were then recorded. The spectra of the initial copolymer and the samples heated to higher temperatures are shown in Figure 4B. The disappearance of the bands at 846 and 907 cm\({}^{-1}\) derived from the vibrations of the oxirane ring can be observed in the spectrum of the sample heated to 265 \({}^{\circ}\)C, compared to the initial spectrum [41]. Furthermore, a band at 1255 cm\({}^{-1}\) representing the stretching vibrations of the oxirane group also disappears [45].