Crystallization kinetics of polymer melts in extensional flow
Tree, David Alan
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https://hdl.handle.net/2142/19299
Description
Title
Crystallization kinetics of polymer melts in extensional flow
Author(s)
Tree, David Alan
Issue Date
1990
Doctoral Committee Chair(s)
McHugh, Anthony J.
Department of Study
Chemical and Biomolecular Engineering
Discipline
Chemical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Chemical
Language
eng
Abstract
A technique to study the kinetics of flow-induced crystallization of polymers in extensional flow has been developed which uses a 4-Roll Mill. The kinetics of a High Density Polyethylene were found to be well described by the Avrami treatment, indicated that the crystallization occurred by sporadic nucleation and one-dimensional growth and were a strong function of temperature and applied stress but were independent of strain history. The kinetics were found to be consistent with the Ziabicki theory for strain-induced crystallization but inconsistent with the theory of uttermost uniformity and an elevated melting point mechanism. The kinematics and stress fields of the 4-Roll Mill flow were measured independently by a tracer particle technique and an application of the Method of Isoclinics respectively allowing comparison to the predictions of several rheological equations of state. The deformation of a polymer droplet suspended in a carrier phase at low Reynolds number and high Weber number was documented. It is recommended that the 4-Roll Mill technique be used for study of other crystallizable polymer systems.
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