Influence of the longest ethylene and isotactic propylene sequences on crystallization elution fractionation of ethylene/propylene copolymers

Crystallization elution fractionation (CEF) is the newest crystallization‐based technique for estimating the chemical composition distribution of ethylene/1‐olefin copolymers. Understanding the separation mechanism of CEF for ethylene/propylene copolymers over their full compositional range is chall...

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Bibliographic Details
Published in:Canadian journal of chemical engineering 2023-09, Vol.101 (9), p.5420-5440
Main Authors: Voraruth, Voradon, Anantawaraskul, Siripon, Mehdiabadi, Saeid, Soares, João B. P.
Format: Article
Language:English
Subjects:
Chemical composition
chemical composition distribution
Copolymers
Crystallization
crystallization elution fractionation
Elution
Ethylene
ethylene/propylene copolymers
Fractionation
Isotacticity
Mathematical models
modelling
polymer microstructure
Polyolefins
Propylene
Sequences
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Summary:Crystallization elution fractionation (CEF) is the newest crystallization‐based technique for estimating the chemical composition distribution of ethylene/1‐olefin copolymers. Understanding the separation mechanism of CEF for ethylene/propylene copolymers over their full compositional range is challenging because the crystallizabilities of the copolymer chains depend on the longest ethylene sequence and on longest isotactic propylene sequence. We developed a mathematical model to describe the CEF mechanism for ethylene/propylene copolymers over the entire compositional range using population balances for the crystallization and dissolution stages. The joint distribution of longest ethylene and isotactic propylene sequences determines how the copolymer populations crystallize and dissolve. The model was validated with experimental CEF profiles of ethylene/propylene copolymers varying from pure ethylene to propylene homopolymers. Crystallization elution fractionation (CEF) model for ethylene/propylene copolymers is developed to investigate how both longest ethylene sequence (LES) and longest isotactic propylene sequence (LIPS) affect CEF fractionation process. LESD × LIPSD bivariant distribution is applied to predict the CEF profiles for EP copolymers with different propylene contents and molecular weights.
ISSN:0008-4034
1939-019X
DOI:10.1002/cjce.25030