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Quantitative Model of Multiple Crystal Growth Rate Minima in Polymers with Regularly Spaced Substituent Groups
Kutlwano Gabana1, Gillian A Gehring1, Xiangbing Zeng2
1Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K.
Macromolecules
|March 4, 2024
Summary
A new theory explains crystal growth rate minima in polyethylene brassylates (PEBs). These anomalies are caused by self-poisoning, where short polymer stems temporarily hinder growth.
Area of Science:
- Polymer science
- Materials science
- Crystallization kinetics
Background:
- Polyethylene brassylates (PEBs) exhibit unusual multiple crystal growth rate minima.
- These minima are linked to specific fold lengths and chemical defects (diester groups).
Purpose of the Study:
- To develop a quantitative theory explaining the observed crystal growth rate minima in PEBs.
- To validate the self-poisoning hypothesis for polymer crystal growth.
Main Methods:
- Developed an analytical rate-equation model incorporating monomer attachment, detachment, and stem lengthening.
- Applied the model to experimental crystallization rate data for PEBs of varying molecular weights.
Main Results:
- The model accurately reproduced experimental crystallization rate curves for PEBs.
- Quantitative fits confirmed that self-poisoning is the cause of the rate minima.
- Identified short, unstable stems as the source of self-poisoning.
Conclusions:
- The developed theory quantitatively explains crystal growth anomalies in PEBs.
- Self-poisoning is a general phenomenon at the growth front of polymer crystals.
- Findings will improve understanding of polymer crystallization and lamellar growth kinetics.
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