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Warpage–crystallinity relations in rotational molding of polypropylene
Author(s) -
Glomsaker T.,
Hinrichsen E.L.,
Larsen Å.,
Doshev P.,
Ommundsen E.
Publication year - 2009
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.21322
Subject(s) - materials science , differential scanning calorimetry , crystallization , crystallinity , polypropylene , composite material , molding (decorative) , isothermal process , crystallization of polymers , kinetics , thermodynamics , physics , quantum mechanics
The authors present a study of the crystalline properties of selected series of polypropylene (PP) materials in relation to their warpage at conditions relevant for rotational molding. The PP materials have different crystallization temperatures and kinetics. The authors study the crystalline features of the materials using hot‐press experiments and differential scanning calorimetry (DSC). In the DSC, the authors do constant cooling rate runs as well as isothermal crystallization and subsequent heating. A multimode crystallization kinetics model was fitted to the DSC cooling runs. Regression analysis was done to relate the results from the crystallization experiments to warpage. The derived empirical model shows that the crystallization temperature, crystallization half‐time, and heat of fusion are the most significant parameters influencing warpage. Materials with warpage deviating from the model average are discussed taking aspects of the multimode kinetics into account. The present work could represent a basic platform for understanding and predicting the warpage during rotational molding process. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers