Collect. Czech. Chem. Commun.
1995, 60, 1733-1740
https://doi.org/10.1135/cccc19951733
Flow-Induced Crystallization of High-Density Polyethylene
Ivan Fortelný, Jana Kovářová and Josef Kovář
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic
Abstract
Crystallization induced by flow in the capillary viscometer was studied for four grades of linear polyethylene. From rheological and DSC measurements it follows that crystallization was induced in all samples under study at temperatures higher than melting temperatures of the same samples crystallized at rest. The maximum temperature of flow-induced crystallization increases with increasing molar mass of polyethylene. Flow-induced crystallization of injection moulding grades of polyethylene only takes place in a limited interval of shear rates. This effect is explained as a consequence of the shear rate distribution in the capillary.