CARBOXYLATED NITRILE RUBBER AS A REACTIVE COMPATIBILIZER FOR IMMISCIBLE BLENDS OF POLY(VINYL CHLORIDE) AND EPOXIDIZED NATURAL-RUBBER

Blends of poly(vinyl chloride) (PVC) and epoxidized natural rubber (EN R) were prepared by melt-blending and studied using a Monsanto rheomet er, infrared spectrophotometer, and dynamic mechanical analyzer. The P VC/ENR blends were found to be self-cross-linkable, but immiscible at 25/75, 50/50, and 75/25 blend ratios. However, addition of a third rea ctive polymer, such as carboxylated nitrile rubber (XNBR), can make th e ternary blend miscible. The quantity of XNBR required to make the bi nary blend miscible depends on the blend ratio of the binary PVC/ENR b lend and increases as the binary blend ratio changes through 25 : 75 t o 50 : 50 to 75 : 25. (C) 1993 John Wiley & Sons, Inc.