Inverse vulcanized sulfur–cycloalkene copolymers: Effect of ring size and unsaturation on thermal properties

•Structure-property relationship of inverse vulcanized polymers were studied.•Cyclic alkenes with different ring size and number of double bonds were used as comonomer.•Tg improves with increase in ring size, number of double bonds and increase in comonomer fraction. Herein, we study the influence of ring size and number of carbon-carbon double bonds of cycloalkene on structure property relation of inverse vulcanized sulfur copolymers. Reaction kinetics was monitored by XRD and the copolymer structure was confirmed by 1H NMR and FTIR spectroscopy. DSC and TGA indicate the significant increase in Tg and thermal stability of the copolymer with increase in ring size and number of double bonds density; respectively. Thermal conductivity of the copolymers (0.083 W/mK at 50 °C) was also considerably reduced compared to the pristine sulfur, which make these copolymer suitable for thermal insulation applications. Moreover, these sulfur-rich copolymers can also be used as potential cathode materials in lithium-sulfur batteries.