Thermal properties and combustibility of cross-linked XNBR/CSM blends

The article describes the measurements results of the thermal properties of cross-linked blends of butadiene?Cacrylonitrile rubber (XNBR, Krynac X.7.50) and chlorosulfonated polyethylene containing different quantity of combined chlorine (CSM24??Hypalon 48, CSM29??Hypalon 20, CSM35??Hypalon 40, and CSM43??Hypalon 30) under inert gas (DSC) and in air (derivatography). The blends were non-conventionally cross linked at a temperature of 150?°C by means of MgO in the presence of stearic acid. The thermal curves obtained were interpreted from the point of view of phase transitions and chemical reactions of the macromolecular components used. It has been found that the elastomers investigated show a good compatibility brought about by the formation of both interpolymeric covalent bonds and interpolymeric and intrapolymeric ionic bridges, which play the role of a chemical compatibilizer. The results of the examinations performed show that the non-conventional cross-linked XNBR/CSM blends prove very good mechanical properties and are self-extinguished in air. Their flammability defined with the value of OI and combustion time in air clearly depends on the type of CSM.