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The lamellar distribution in isotactic polypropylene modified by nucleation and processing
Author(s) -
Romankiewicz Anna,
Sterzynski Tomasz
Publication year - 2002
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/1521-3900(200203)180:1<241::aid-masy241>3.0.co;2-9
Subject(s) - lamellar structure , nucleation , tacticity , materials science , polypropylene , elongation , phase (matter) , crystallography , polymer chemistry , chemical engineering , composite material , thermodynamics , polymer , chemistry , ultimate tensile strength , organic chemistry , physics , polymerization , engineering
An isotactic polypropylene was modified with specific α ‐ phase and β ‐ phase nucleation agents. The modification by processing during extrusion was realised by means of molten state elongation with various stretching ratios λ, between 7.11 and 1.67. The lamellar thickness distribution was evaluated for non‐elongated and elongated samples using the DSC melting curves, by an application of the general Thomson ‐ Gibbs equation. A significant influence of heterogeneous nucleation on the lamellar distribution was confirmed. The morphological effects are visible as a shift of the maxima of the lamellar distribution and as the elongation and nucleation dependent appearance of lamellae with smaller (below 12 nm) and bigger (above 25 nm) thickness.