Recently, new methods have been developed for the utilization of elemental sulfur as a feedstock for novel polymeric materials. One promising method is the inverse vulcanization, which is used to prepare polymeric structures derived from sulfur and divinyl comonomers. However, the mechanical and electrical properties of the products are virtually unexplored. Hence, in the present study, we synthesized a 200 g scale of amorphous, hydrophobic as well as translucent, hyperbranched polymeric sulfur networks that provide a high thermal resistance (>220 °C). The polymeric material properties of these sulfur copolymers can be controlled significantly by varying the monomers as well as the feed content. The investigated comonomers are divinylbenzene (DVB) and 1,3-diisopropenylbenzene (DIB). Plastomers with low elastic content and high shape retention containing 12.5%–30% DVB as well as low viscose waxy plastomers with a high flow behavior containing a high DVB content of 30%–35% were obtained. Copolymers with 15%–30% DIB act, on the one hand, as thermoplastics and, on the other hand, as vitreous thermosets with a DIB of 30%–35%. Results of the thermogravimetric analysis (TGA), the dynamic scanning calorimetry (DSC) and mechanical characterization, such as stress–strain experiments and dynamic mechanical thermal analysis, are discussed with the outcome that they support the assumption of a polymeric cross-linked network structure in the form of hyper-branched polymers.

Spherical, micrometer-sized, azide-functional particles were produced through dispersion copolymerization of styrene and vinylbenzyl azide (VBA, 1–100 wt% of monomer feed) in ethanol in the presence of stabilizers. The obtained microspheres were characterized by SEM, disc centrifuge, FT-IR and NMR spectroscopy, elemental analysis, DSC, and TGA, had measured azide loadings of up to 5.58 mmol g⁻¹, and average diameters that decreased with increasing azide content from 2.8 to 0.8 μm. Microspheres were irradiated at a wavelength of 254 nm resulting in crosslinking based on azide-to-nitrene decomposition and subsequent C–H insertion and CC addition reactions. The conversion of azide functionality was monitored by FT-IR spectroscopy, elemental analysis, and DSC and was found to roughly follow first-order kinetics with increased rates found for microspheres with lower azide contents. Photo-crosslinking preserved shapes and size distributions and, above a crosslinking degree of 10%, prevented microsphere dissolution in good solvents. By controlling the irradiation time, the amount of azide consumed for photo-crosslinking could be precisely adjusted. Residual azide groups spared during the irradiation were shown to be amenable to highly efficient CuAAC click modification with a fluorescent dye, Rhodamine B propargyl ester. Given the demand for functional crosslinked microspheres and the inherent difficulties associated with common synthetic strategies in producing such materials, this methodology based on two orthogonal chemistries of the azide functionality provides simple access to well-defined microspheres with customizable degrees of crosslinking and functional group densities.

With surface areas of up to 467 m ² g ⁻¹ , crosslinked azide- and alkyne-functional poly(styrene- co -divinylbenzene) microparticles enable versatile modification throughout the particle.