This article describes the test results of thermal properties and flammability of the unconventionally cross-linked blends
of chlorosulfonated polyethylene (CSM) and butadiene–styrene rubber (SBR) by means of zinc oxide or nano-zinc oxide. The thermal
curves have been interpreted from the point of view of the chemical transitions of elastomers and their blends. It has been
found that the content of combined chlorine in CSM exerts a significant influence on the cross-linking kinetics of CSM/SBR
blends, their thermal properties and flammability.