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Cavitation during deformation of polymers on the example of polypropylene
Author(s) -
Pawlak Andrzej
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.36565
Subject(s) - cavitation , materials science , deformation (meteorology) , lamellar structure , lamella (surface anatomy) , tacticity , radius of gyration , composite material , perpendicular , amorphous solid , polymer , scattering , polypropylene , radius , phase (matter) , crystallography , optics , thermodynamics , chemistry , geometry , physics , mathematics , computer security , organic chemistry , computer science , polymerization
Cavitation during uniaxial deformation of isotactic polypropylene (PP) was studied in samples having different amounts of α and β crystals. It has been shown that deformation is always accompanied by neck formation. Because the very beginning the plastic deformation is accompanied by cavitation. The scale of cavitation, determined with the use of X‐ray scattering and volume measurements increases with an increase of the content of β phase in the examined samples. Cavities change their shape with deformation—at first they are elongated perpendicularly to the direction of stretching, next, at the strain of 1.5, they reorient in the direction of deformation, which is connected with changes in the surrounding lamellar structure. The calculations of Guinier's radius showed that two populations of voids are present in deformed PP samples, characterized by the gyration radii of 5 and 13 nm for small deformations. Estimations based on the volume increase and sizes of cavities indicate that typically more than one cavity are present in amorphous layers adhering to lamella surfaces. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012