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Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Chain Length Dependence of Chemically Controlled Reactions in Polymerization
Yue Mu1, Zhen Liu1, Michelle L Coote2
1School of Chemical Engineering, East China University of Science and Technology, Shanghai200237, China.
Journal of the American Chemical Society
|July 30, 2026
Summary
Chemically controlled polymerization reactions show chain length effects, challenging traditional assumptions. Multiscale modeling reveals entropy contributions significantly impact equilibrium constants in polymer-polymer reactions.
Area of Science:
- Polymer Chemistry
- Chemical Kinetics
- Thermodynamics
Background:
- Traditional polymerization models assume chain-length-independent rate coefficients.
- This assumption is challenged by the influence of chain length on reaction kinetics and thermodynamics.
Purpose of the Study:
- To investigate chain length effects in chemically controlled polymer-polymer reactions.
- To challenge the assumption of chain-length-independent rate coefficients using multiscale modeling.
Main Methods:
- Multiscale modeling was employed to study polymerization processes.
- Case studies included reversible addition-fragmentation chain transfer (RAFT) polymerization and Diels-Alder step-growth polymerization.
Main Results:
- Significant chain length dependence was observed in equilibrium constants (Keq) due to entropy contributions.
- Delayed convergence of reaction entropy was noted in polymer-polymer reactions, persisting to high degrees of polymerization (DP).
- Chain length effects were found to be fundamental, arising from entropic considerations.
Conclusions:
- Entropy contributions lead to significant chain length dependence in chemically controlled polymer-polymer reactions.
- Findings provide a mechanistic basis for experimental discrepancies in rate coefficients and rate retardation in RAFT systems.
- Highlights the importance of considering chain length effects in polymerization kinetics and thermodynamics.
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