Rheological, mechanical, thermal, and morphological properties of polypropylene/ethylene-octene copolymer blends

Rheological and morphological studies were performed on polymer blends of e thylene-octene copolymer [polyethylene elastomer (PEE)] and polypropylene ( PP). The viscosities of PEE, PP, and PEE/PP blends were analyzed using an I nstron capillary rheometer and a Rheometrics Dynamic Stress Rheometer, SR 2 00. A non-Newtonian flow behavior was observed in all samples in the shear rate range from 27 to 2700 s(-1), whereas at shear rates in the range from 0.01 to 0.04 s(-1), a Newtonian flow behavior was verified. The scanning el ectron micrographs showed that dual-phase continuity may occur between 50 a nd 60 (wt %) of PEE. This result is consistent with the Sperling's model. T he mechanical analysis showed that PEE/PP, with 5 wt % of PEE, presented an increase on the mechanical properties and as the PEE content increased, a negative deviation in relation to an empirical equation was observed. Therm al analysis showed that there were no change in the crystallization behavio r of the matrix when different elastomer contents were added. Dynamic mecha nical thermal analysis showed that samples with low PEE contents presented only one peak, indicating a certain degree of miscibility between the compo nents of these blends. (C) 2000 John Wiley & Sons, Inc.