STUDIES ON THE THERMODYNAMIC COMPATIBILITY OF BLENDS OF POLY(VINYL CHLORIDE) AND NITRILE RUBBER

Inverse gas chromatography has been used to investigate the thermodynamic compatibility of blends of poly(vinyl chloride) (PVC) and nitrile rubber (NBR) as a function of blend composition and acrylonitrile (AN) content of NBR. The values of the polymer-polymer thermodynamic interaction parameters (chi23' and B23) and the solubility parameter (delta) of the polymers and their blends were determined with the help of the measured retention data for various polar and non-polar probes in the pure and mixed stationary phases of these polymers. Out of all the probes studied only dioxane and cyclohexanone have similar delta values to those of the blends. The B23 values for the PVC/NBR blends were approximately -0.1 and -1.1 cal ml-1 depending on the AN content of NBR. Thus, the two polymers are fairly compatible and show increased compatibility with increase in AN content of NBR.