## 3 Results
As for the DVB-\(co\)-BMIPS copolymer decomposition, the FTIR spectra collected in the second step demonstrated bands originating from carbon dioxide, carbon monoxide, water and sulfur dioxide. The analysis of FTIR spectra also showed that a much greater amount of carbon dioxide had been emitted in the second stage of copolymer decomposition. This was due to the intense oxidation of the products obtained in the first stage. To gain more comprehensive information about the thermal behavior of the studied copolymers, further DSC measurements were carried out. Figure 9 displays the DSC curves obtained in helium and air atmospheres. For the curves obtained in helium, both exothermic and endothermic peaks are visible. The first endothermic peak is connected with the evaporation of moisture from the internal structure of the copolymers. All samples were dried in vacuo before experiments. However, as they were highly porous and chemically diversified they easily adsorbed moisture from the atmosphere during weighting. Interestingly, the presence of adsorbed water in the samples is practically invisible on the TG/DTG curves. For most samples, the first endothermic peak was followed by an exothermic one that could be attributed to the post cross-linking of unreacted double bonds still present in the polymer matrix. Only the DVB-\(co\)-ST copolymer exhibited no exothermic peaks. which indicated a high degree of double-bond conversion. However, this polymer started to decompose at the lowest temperature of all investigated materials. The decomposition process was represented by the second endothermic peak with a maximum in the 405-450 \({}^{\circ}\)C range. Figure 8: TG, DTG and Gram-Schmidt curves of copolymers obtained under air atmosphere. (**a**); DVB-\(co\)-ST, DVB-\(co\)-NVP and DVB-\(co\)-EGDMA; (**b**) DVB-\(co\)-BMB, DVB-\(co\)-BMPS and DVB-\(co\)-BMPM. On the other hand, only exothermic events were manifested on DSC curves received in the air atmosphere. At the beginning, the oxidation of unreacted double bounds occurred. This process was especially visible for DVB-_co_-BMB, DVB-_co_-NVP and DVB-_co_-EGDMA copolymers, which indicated a considerable amount of double bonds remaining in these materials. The second peaks with a maximum above 300 \({}^{\circ}\)C pointed to the thermal degradation of functional groups and linear fragments of the polymeric structure. Above 450 \({}^{\circ}\)C, the oxidation reaction of the cross-linked residues took place, which was confirmed by the FTIR spectra of emitted gases. The main detected gases were carbon dioxide and water. The high thermal stability of the studied copolymers allowed inverse gas chromatography to be applied for further characterization. Table 6 presents [PERSON] retention indices for the [PERSON] test substances determined at 140 \({}^{\circ}\)C. On their basis, overall polarity was assessed and a polarity index (\(\Sigma\Delta I\)) was calculated. A polarity index ranks adsorbents according to the sum of the McReynolds' constant of the test substances. As a rule, the higher the polarity index, the more polar the adsorbent. As expected, the lowest value of \(\Sigma\Delta I\) (315) was observed for the DVB-_co_-ST copolymer, which did not contain a functional group. The incorporation of even an inconsiderable amount of a methacrylate group into a polymer matrix resulted in an increase of the overall polarity value to 357 as could be seen for DVB-_co_-BMB. The equimolar reaction of DVB with aliphatic EGDMA gave a material with polarity exceeding 400, whereas the aromatic BMPM generated a further increase of polarity to 494. The additional presence of the sulfone group led to the highest value of overall polarity (518) among all studied copolymers. Worth noticing is that materials with a high polarity (510) could be also obtained by applying VP as a functional monomer. Figure 9: DSC curves of copolymers obtained in helium (**left**) and air (**right**) atmosphere.