STUDIES ON THE DYNAMICALLY VULCANIZED POLYPROPYLENE (PP) BUTADIENE STYRENE BLOCK-COPOLYMER (SBS) BLENDS - MECHANICAL-PROPERTIES

Unvulcanized and dynamically vulcanized blends of isotactic polypropyl ene (PP) and butadiene styrene block copolymer (SBS) in the compositio n range of 10-40 wt % SBS were prepared by melt mixing in an internal mixer and evaluated for impact and tensile properties. Dynamic vulcani zation of blends gave superior mechanical properties. Systematic chang es with varying blend composition were found in stress-strain behavior in both the blend systems. The effect of blend composition on the sta te of dispersion and morphology of the dispersed phase droplets were s tudied by scanning electron microscopy. Analysis of the yield stress d ata in terms of various theoretical models revealed the variation of s tress concentration effect with blend composition and higher interphas e adhesion in dynamically vulcanized blends. (C) 1997 John Wiley & Son s, Inc.