Measurements of the rheological behavior of a crystallizing polymer by an “inverse quenching” technique
- 1 March 2003
- journal article
- Published by Society of Rheology in Journal of Rheology
- Vol. 47 (2), 563-576
- https://doi.org/10.1122/1.1545080
Abstract
In this paper we show that a suitable thermal history can be used to produce a polymer melt in which a fixed amount of crystalline phase has been frozen. We call this novel method “inverse quenching,” since a stable amorphous/crystalline system is obtained by heating up the sample rather than cooling it down. If the inverse quenchingtemperature is suitably chosen, the polymer can remain stable for a long time, thus allowing different types of experimental measurements. Here we first prove the validity of the inverse quenching method in quiescent crystallization conditions, and then we use the inverse quenching method to perform rheological measurements on an isotactic polypropylene at a constant degree of crystallization. In particular, steady-state viscosity measurements in the early crystallization stages are reported for the first time, showing that the viscosity at low shear rates is much larger than that of the purely amorphous melt even for small values of crystallinity. The technique is also used to study the liquid-to-solid transitional behavior of the crystallizingpolymer, which can be seen as a gelation process, at temperatures that are forbidden to traditional techniques. Such measurements are shown to provide further, robust validation of this novel method.Keywords
This publication has 14 references indexed in Scilit:
- Effects of Molecular Weight on the Isothermal Crystallization of Poly(1-butene)Macromolecules, 2002
- A continuum model for flow-induced crystallization of polymer meltsJournal of Rheology, 1999
- Determination of the Equilibrium Melting Temperature of Polymer Crystals: Linear and Nonlinear Hoffman−Weeks ExtrapolationsMacromolecules, 1998
- Elongational flow-induced crystallization in supercooled poly(ethylene terephthalate) with different crystallization habitPolymer, 1998
- The Role of Long Molecules and Nucleating Agents in Shear Induced Crystallization of Isotactic Polypropylenes**International Polymer Processing, 1997
- Extensional flow-induced crystallization of a polyethylene meltColloid and Polymer Science, 1993
- Polypropylene nucleation on a glass fibre after melt shearingJournal of Materials Science, 1992
- An experimental study of the kinetics of polymer crystallization during shear flowPolymer Engineering & Science, 1976
- Flow-induced crystallization of polyethylene meltsJournal of Materials Science, 1975
- Theory of formation of polymer crystals with folded chains in dilute solutionJournal of Research of the National Bureau of Standards Section A: Physics and Chemistry, 1960