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Plastic flow and multiple fracture of semicrystalline polymers
Author(s) -
Prut E. V.
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910410108
Subject(s) - materials science , polypropylene , crystallinity , polymer , tacticity , extrusion , flow (mathematics) , fracture (geology) , yield (engineering) , plasticity , elongation , composite material , thermodynamics , mechanics , ultimate tensile strength , polymerization , physics
The mechanism of plastic flow of isotactic polypropylene is considered in terms of Eyring's equation. It is demonstrated that to explain the dependence of the yield point on temperature a dependence of activation volume on overcooling (T m ‐T) must be admitted. The effects of drawing rate and temperature on the ultimate elongation of polypropylene are discussed in the case of two‐step drawing. The critical conditions of extrusion in solid state are considered. Criteria of transformation of a steady flow into unsteady state are suggested. Multiple fracture of semicrystalline polymers under critical conditions of plastic is described.