Effect of various saturation levels of hydrogenated nitrile-butadiene rubber on plasticized polyvinyl chloride performance

Plasticized polyvinyl chloride (PVC) burns easily and generates a lot of smoke during combustion. In order to improve the comprehensive performance of plasticized PVC, hydrogenated nitrile-butadiene rubber (HNBR) with different degrees of saturation (88%, 94% and 99%) were melt blended with plasticized PVC. Compared to the plasticized PVC without HNBR, the glass transition temperature decreased from −10.6 to −26.0°C, the initiation temperature for thermal degradation increased from 272 to 281°C, the elongation at break enlarged from 316% to 477%, and the permanent set dropped from 72% to 61% when HNBR was added to plasticized PVC at a ratio of 30 parts per hundred parts of resin. However, this resulted in a weakening of tensile strength of the plasticized PVC. Additionally, in the cone calorimetry test, the total smoke production of the PVC/HNBR blends (from 18 to 22 m²) was lower than that of the PVC control (23 m²) and the time to ignition was increased from 26 to 32 s. As a result, PVC/HNBR is expected to gain popularity in the rubber and plastic pipe, wire, and cable sheathing industries. Highlights: Plasticized PVC improves thermal stability by melt blending with HNBR. All PVC/HNBR samples have excellent low-temperature resistance. The addition of HNBR decreases the burning smoke density of plasticized PVC.