Related Experiment Video
Updated: May 19, 2026

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Formation of Anisotropic Flow-Induced Morphologies above the Equilibrium Melting Temperature in Isotactic
Benson J Jacob1, Xiaoshi Zhang2, Jongkyeong Kim3
1Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Abstract:
Shearing an isotactic polypropylene melt, even above its equilibrium melting temperature (T m° ∼ 187 °C) leads to the formation of stable flow-induced precursors. Anisotropic structures result from shearing at temperatures as high as 220 °C (>30 °C above T m°), and are no longer generated at shearing temperatures exceeding 230 °C. The long periods increase with deformation, accompanied by a change in structural morphology. The crystallization kinetics were strongly affected by flow at shearing temperatures near T m° and persist at even higher shearing temperatures, as chains continue to be aligned and stretched with large deformations, perhaps further stabilized by stretched chains adsorbing onto heterogeneous impurities from polymerization.
Related Concept Videos
Polymer Classification: Stereospecificity
Polymer Classification: Crystallinity
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Phase Transitions: Melting and Freezing
Classification and Mechanical Properties of Synthetic Polymers
Molecular Weight of Step-Growth Polymers
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
Plastic Behavior

