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Weld line structures and properties in injection molded polypropylene
Author(s) -
Malguarnera S. C.,
Manisali A. I.,
Riggs D. C.
Publication year - 1981
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.760211706
Subject(s) - materials science , weld line , polypropylene , nucleation , mold , welding , composite material , ultimate tensile strength , brittleness , annealing (glass) , elongation , atmospheric temperature range , chemistry , organic chemistry , physics , meteorology
Abstract Weld regions are formed wherever polymer flow fronts meet. The present study examines the effects of melt temperature, mold temperature, mold cooling conditions, injection speed and annealing on the tensile properties and morphological structure of weld regions in four commercially available polypropylene resins. One of the resins contained nucleation particles. Scanning electron micrographs of the weld region revealed a wide range of morphologies from very strong welds which formed part of a stable neck to brittle failures at low elongation caused by the presence of large nucleation particles in the weld region. The melt temperature, mold temperature, and annealing had the greatest effect on the weld region's tensile properties.