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The toughness of copolymers of polypropylene
Author(s) -
Fernando P. L.,
Williams J. G.
Publication year - 1981
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760211504
Subject(s) - materials science , crazing , polypropylene , copolymer , composite material , toughness , ethylene , natural rubber , acrylonitrile , polybutadiene , polymer , biochemistry , chemistry , catalysis
Abstract A series of fracture mechanics tests of a set of random and impact copolymers of polypropylene, in which the ethylene content was varied, is described. The plane strain toughness is found to change from the homopolymer value, but thereafter to be independent of ethylene content. The yield stress of the impact copolymers decreases markedly with ethylene content, while that for random copolymers increases only slightly. This is reflected in toughness values in tension. A comparison with the behavior of other rubber‐modified materials is made and it is concluded that crazing is an important mechanism in polypropylene and is perhaps more rate and temperature sensitive than in acrylonitrile‐butadiene‐styrene (ABS).