Ozone resistance of vulcanized NBR-PVC blends

A relationship between structure and ozone resistance of the vulcanized 70: 30 blends of butadiene-acrylonitrile rubbers (NBR) and poly(vinyl chloride) (PVC) was studied. The samples were prepared from NBR of the SKN-18, SKN-26, and SKN-40 grades and PVC (obtained by emulsion or suspension polymerization) by methods of high- and low-temperature blending followed by treatment in a thermostat. The properties of blends (including homogeneity, interphase layer structure, and ozone resistance) were studied by methods of stress relaxation, EPR, and IR spectroscopy. A mechanism of the ozone-protective action of thermoplast (PVC) in the blends with NBR is considered for the systems possessing various degrees of homogeneity.