Toughness assessment of elastomeric polypropylene (ELPP) by the essential work of the fracture method

✍ Scribed by D. E. Mouzakis; M. Gahleitner; J. Karger-Kocsis

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 349 KB
• Volume: 70
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19981031)70:5<873::aid-app6>3.0.co;2-q

✦ Synopsis

The essential work of the fracture (EWF) method was employed to determine the fracture performance of thermoplastic polypropylene (PP) elastomers. Three types of elastomeric polypropylene (ELPP) of homo-and copolymer nature based on different catalysts were involved in this study. Tests were carried out in both I and III fracture modes to check the applicability of the EWF approach for such elastomers. It was found that the trouser tearing test (mode III) overestimates both the specific essential (w e ) and plastic work (w p ) terms when the tearing resistance of the ELPP is higher than the resistance to tensile loading. With decreasing crystallinity (i.e., by decreasing length of the stereoregular chain segments of the block copolymers or increased content of comonomer) w e increased, whereas in respect to w p, , an opposite tendency was found. This was interpreted by possible changes in the thermoreversible network structure of the ELPP in which crystalline domains act as network knot points in the amorphous PP matrix.