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Structure development in processing of polypropylene films with additives
Author(s) -
Radhakrishnan S.,
Kane K.,
Kadu A.,
Natu H. P.
Publication year - 1995
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.1995.070580312
Subject(s) - crystallite , materials science , polypropylene , birefringence , crystallization , extrusion , amorphous solid , composite material , spherulite (polymer physics) , isothermal process , diffraction , polymer , crystallography , chemical engineering , optics , chemistry , thermodynamics , physics , metallurgy , engineering
The crystallization behavior, modification of crystalline form, and orientation in polypropylene processed by blow film extrusion was studied as a function of processing parameters as well as different types of additives. The isothermal crystallization rate was greatly enhanced in the presence of certain additives, especially CaCO 3 . The crystalline form was predominantly α type in both compression molded or blow extruded films. However, there was an unusually large intensity of the α 040 peak in the X‐ray diffraction of the latter case films. The variation of the peak intensities and the increase of birefringence with increase of take‐up speed has been explained on the basis of orientation induced by uniaxial stress in the machine direction. This orientation contained two components, namely the orientation of the b axis of the crystallites and the orientation of loosely bound polymer chains in the amorphous regions. © 1995 John Wiley & Sons, Inc.