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Injection molding of polypropylene discs. I: Effect of holding pressure on orientation distribution
Author(s) -
Sjönell Ylva,
Terselius BjöRn,
Jansson JanFredrik
Publication year - 1995
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.760351109
Subject(s) - polypropylene , materials science , orientation (vector space) , molding (decorative) , composite material , amorphous solid , polymer , crystallography , geometry , chemistry , mathematics
It is well known that the injection molding process has a major impact on the properties of injection‐molded polymers. In this study, the effect of the holding pressure on the orientation in injection‐molded discs of polypropylene has been examined. The orientation has been determined by IR‐dichroism and the orientation factors calculated according to Herman's orientation function, the average factor as well as the crystalline and the amorphous. The distribution of the orientation in the length as well as in the depth direction has also been exmined in order to understand how the flow has propagated in the cavity during both the filling and the packing phases. The results show that the holding pressure clearly affected the orientation, but that it was an unevenly distributed effect over the disc.