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Ductile tearing instability in some engineering thermoplastic blends
Author(s) -
Dekkers M. E. J.,
Hobbs S. Y.
Publication year - 1987
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.760271509
Subject(s) - materials science , tearing , composite material , fracture toughness , thermoplastic , fracture mechanics , polycarbonate , toughness , bending , fracture (geology) , phenylene , charpy impact test , instability , polymer , physics , mechanics
The stability of ductile crack growth in two engineering thermoplastic blends is examined. The blends are a poly(phenylene oxide)/nylon 6,6 blend and a poly(butylene terephthalate)/polycarbonate blend. Fracture tests were performed with single‐edge notched specimens in tension and three‐point bending over a wide range of test speeds. Both larger radius notches and longer specimens were found to promote ductile tearing instability. This behavior is attributed to the higher driving force for crack growth produced by increased elastic energy storage before crack initiation. Over a certain range of test speeds, these factors lead to a novel effect of notch sharpness on toughness; a sharp notch gives rise to a higher fracture energy than does a blunt notch. The results are discussed in terms of the tearing modulus concept developed by Paris and co‐workers.