Influence of morphology on the toughening mechanisms of polypropylene modified with core–shell particles derived from thermoplastic elastomers

✍ Scribed by G.-M. Kim; G. H. Michler; M. Gahleitner; R. Mülhaupt

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 331 KB
• Volume: 9
• Category: Article
• ISSN: 1042-7147
• DOI: 10.1002/(sici)1099-1581(1998100)9:10/11<709::aid-pat833>3.0.co;2-4

✦ Synopsis

The micromechanical deformation processes of impactmodified polypropylene (PP) with core± shell particles derived from PP/EPR (ethylene± propylene± rubber) block copolymers and PP/PA/SEBS-g-MA (polypropylene/polyamide/polystyrene-block-poly(ethene-co-but-1-ene)-block-polystyrene-graft-maleic anhydride) graft copolymers have been investigated by in-situ tensile tests in high-voltage electron microscopy. Morphology studies in transmission electron microscopy show that the morphology of modifier particles is drastically affected by their concentration. It was found that the driving mechanism for the initiation of plastic deformation is a controlled microvoid formation, which is caused by cavitation in the stretched rubber shell under mechanical loading. According to the inherent properties and phase structures of modifier particles, a single or multiple cavitation appears with or without fibril formation at the interface between the modifier particles and the matrix. The Predominant mechanism for the improvement of toughness is the shear yielding of the ligaments of matrix material induced by local stress concentration by the microvoids.