## 3 Results and Discussion
### Thermal Properties  
The thermogravimetric analysis (Figure 5) shows thermal resistance up to 220 \({}^{\circ}\)C of all types of synthesized sulfur copolymers. Between 200-300 \({}^{\circ}\)C, there is a steep, massive weight% loss which is related to the decomposition of the sulfur. By increasing the temperature, no further mass loss occurs. The residues of the pS-DVBs correlate with the respective incorporated monomer content. The residue of pS-DIBs seems to be independent of the incorporated monomer content. The mass residue has a constant value of 17% \(\pm\) 2%. The high residue after the decomposition indicates that presumably a cross-linking network is present. Figure 4: SEM-image of a crude sulfur copolymer with holes and plain surface (**a**,**d**); crude sulfur copolymer with sulfur crystals (**b**,**e**) and heated copolymer with cracks; treated with the hot press (**c**,**f**). Above pS-DVB is shown, and below pS-DIB is shown with 15 wt % vinyl monomer. Figure 3: SEM-image of pS-DVB with 30 wt % DVB: (**a**) section with sulfur crystals and agglomerates; (**b**) sulfur crystals with spherical dots; (**c**) spherical dots on sulfur crystals and copolymer surface. In comparison with the results of Pyun, the decomposition curve of pS-DVB is shifted to a higher temperature (+20 \({}^{\circ}\)C), which indicates a higher temperature stability [11]. The course of the decomposition curve of the pS-DIB is neither comparable nor the uniform residue explainable without any dependence of the monomer content. The decomposition temperature corresponds to 5% weight loss of the initial mass, when the decomposition starts. This value occurred in all samples at an average temperature of 222 \(\pm\) 9 \({}^{\circ}\)C (Table 1). Different publications report on similar results above 200 \({}^{\circ}\)C of the decomposition temperature [8; 11; 14]. [PERSON] et al. have analyzed the leaching out in the annealing process between 300-400 \({}^{\circ}\)C by means of EDS (Energy-dispersive X-ray spectroscopy) and have attributed it to the decrease of sulfur. Independent of the DIB content, the decay contains approximately 90 wt % sulfur. By means of the supported quantitative XPS analysis (X-ray photoelectron spectroscopy), it was determined that the remaining sulfur does not alter significantly after annealing. In the remaining compound, organic sulfate groups (168.0 eV) were identified, including such species such as thioethers or disulfides (164.0 eV), C-S (163.98 eV), SO\({}_{\rm x}\) and R-SO\({}_{\rm x}\)-R\({}^{\prime}\) (167.88 eV) as well as C=S (161.5 eV, low intensity). With 80% of the sulfur signals, the C-S bonds have the highest quantity, even though they represent only an average of 8% of the total remaining structure. This indicates an \"inverse vulcanization\" architecture of the copolymer by retention after the annealing process. Independent of the sample, there is a critical amount of sulfur between 7.4%-14.1%, which remains after annealing. However, the carbon composition fluctuates very strongly. Probably, more stable mono- or disulfide linkages are formed, which stabilize the remaining sulfur content, and a higher initial sulfur concentration preferentially forms longer polysulfide chains (S-S\({}_{\rm n}\)-S) between the -C-S linkages. The longer chains containing S-S bonds tend to decompose at high temperatures under sublimation. The observed melting point in the first heating step in the DSC-thermogram of pS-DVB (<15 wt % DVB, Figure 6a) and pS-DIB (15-25 wt % DIB, Figure 6b) is caused by small amounts of non- converted