FLOW BEHAVIOR OF BLENDS OF POLY(ETHYLENE-CO-ACRYLIC ACID) AND EPOXIDIZED NATURAL-RUBBER

Processability and rheological properties of the blends of poly(ethyle ne-Co-acrylic acid)(PEA) and epoxidised natural rubber (ENR) have been studied by a Monsanto Processibility Tester MPT). The blends were fou nd to be miscible during reactive processing due to chemical interacti on via esterification reaction at higher proportion of PEA. The rheolo gical properties were studied at three different temperatures (120 deg rees C, 130 degrees C and 150 degrees C), five different shear rates i n the range from 122 s(-1) to 2452 s(-1) and at three different shear stresses (i.e., 400, 500 and 600 kPa). The melt viscosities of the ble nds at 120 degrees C and 130 degrees C show a positive deviation at lo wer shear rates and shear stress and at higher proportions of PEA and a negative deviation at higher shear rates and shear stress and lower proportion of PEA, where as at higher temperature (i.e. at 150 degrees C) of melt processing the viscosities show positive deviation (at all shear rates for all the blends) with respect to that calculated by ad ditivity rule. This variation in melt viscosoties has been explained o n the basis of chemical reaction via esterification leading to grafted structure i.e., PEA-g-ENR.