Morphology and physical properties of SAN NBR blends: The effect of AN content and melt viscosity of SAN

To study the effect of dispersed poly(butadiene-co-acrylonitrile) (NBR) rub ber size on the physical properties of poly(styrene-co-acrylonitrile) (SAN) /NBR blends, SANs with various melt viscosities and acrylonitrile (AN) cont ents were examined. The dispersed size of NBR, whose AN content is 30 wt %, was reduced as the melt viscosity of the SAN matrix was increased or as th e AN content of the SAN matrix was reduced in the range of 19 - 32 wt %. As the melt viscosity of the SAN matrix was increased, the damping peak of th e NBR phase moved to a higher temperature, and as the AN content of SAN was reduced, the damping peak of the SAN phase moved to a lower temperature. H igher values of impact strength and elongation at break and reduced yield b ehavior at a low shear rate were observed at a finer dispersion of NBR. (C) 1999 John Wiley & Sons, Inc.