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Skin‐core structure–fatigue behavior relationships for injection‐molded parts of polypropylene. I. Influence of molecular weight and injection conditions on the morphology
Author(s) -
Trotig JeanPierre,
Verdu Jacques
Publication year - 1987
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.1987.070340101
Subject(s) - polypropylene , crystallinity , materials science , morphology (biology) , core (optical fiber) , mold , composite material , branching (polymer chemistry) , injection moulding , polymer chemistry , biology , genetics
The skin‐core structure of various injection‐molded samples of PP differing by molecular weight and the injection conditions—essentially injection rate and holding pressure—has been studied by microscopy, DSC, WAXS, and IR dichroïsm on microtome sections. The depth distributions of the degree of crystallinity, macromolecular orientation, and beta phase fraction reveal a complex stratification of the morphology. The importance of the holding pressure and its delay of application after the mold filling are underlined.