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An anomaly in the necking behavior of polyethylene, Part 3
Author(s) -
Gedde U. W.,
Terselius B.,
Jansson J.F.
Publication year - 1980
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.760201106
Subject(s) - necking , materials science , differential scanning calorimetry , crystallinity , scanning electron microscope , composite material , polyethylene , polarized light microscopy , ultimate tensile strength , glass transition , polymer , optics , thermodynamics , physics
Differential scanning calorimetry (DSC) measurements, polarized light microscopy and scanning electron microscopy (SEM) studies are reported on neck fibers formed by constant uniaxial tensile loading of polyethylene specimens at temperatures ranging from 298 to 353 K. The DSC measurements indicate that the temperature of the melting peak ( T peak ) of the neck fibers is closely related to the fibrilinity, i.e., the content of complete fibrillar structure, and that T peak and thus fibrillinity of the fractured neck fibers is sensitive to the nominal stress in the region of marked transition. A previously proposed hypothesis concerning the appearance of a marked transition in the necking/fracture behavior of high density and high molecular weight polyethylene is thereby supported. The polarized light microscopy showed a correlation between the zone length of the transformation from spherulitic to fibrillar structure and the previously reported distinctness in neck formation. The crystallinity determinations obtained from the DSC measurements and the SEM observations confirmed the suggestion previously made that the density decrease in the fractured neck fibers of a high density polyethylene with M n = 21.6 × 10 3 and M w = 199 × 10 3 is a result of void formation.