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Ductile‐brittle transition behavior of short‐chain branched polyethylenes at 80°C
Author(s) -
Yeh Jentaut,
Lee WenShuan
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021961022
Subject(s) - brittleness , materials science , composite material , stress (linguistics) , displacement (psychology) , transition temperature , intensity (physics) , stress intensity factor , forensic engineering , fracture mechanics , physics , optics , psychology , philosophy , linguistics , superconductivity , quantum mechanics , psychotherapist , engineering
A systematic study on the ductile‐brittle transition of short‐chain branched polyethylenes (SBPEs) is reported. The values of threshold stress intensity, the time corresponding to the point of ductile‐brittle transition and the failure time ( t f ) of samples which failed in ductile and brittle regions were found to increase significantly with increasing branch length of the SBPEs. The fracture kinetics and the morphology at the notched root were distinguished for SBPE samples that failed in ductile and brittle regions. The values of (CC(notch opening displacement at the roof of notch)–BB(the thickness of the craze))/(AA(notch opening displacement at the surface of the specimen)–CC) are less than or equal to about 0.3 for all samples which failed in the brittle region, and these values are only about 20–30% of those of the samples which failed in the ductile region. Finally, an equation was developed to predict t f of SBPEs which failed in the ductile and brittle region in terms of stress intensity, branch length and other material and experimental parameters.