Experimental and statistical modelling of gelation in aspartate-based polyurea networks

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F25%3A00639838" target="_blank" >RIV/61389013:_____/25:00639838 - isvavai.cz</a>

Alternative codes found

RIV/00216208:11320/25:10508433

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0032386125010869?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0032386125010869?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.polymer.2025.129100" target="_blank" >10.1016/j.polymer.2025.129100</a>

Result language

angličtina

Original language name

Experimental and statistical modelling of gelation in aspartate-based polyurea networks

Original language description

This research investigates the complex crosslinking mechanism and kinetics of aspartate-based polyurea networks for high-performance coatings, focusing on a puzzling “gelling paradox”: we observed that the addition of dibutyltin dilaurate (DBTDL) dramatically extends the gel time (by 7 ×), while counterintuitively decreasing the gel conversion. This behaviour contradicts the Flory–Stockmayer theory, which predicts the gel conversion independent of reaction rate in simple gelling systems. Through a detailed investigation employing FTIR, NMR, and MALDI-TOF techniques, the complex underlying crosslinking chemistry has been elucidated. We found that beyond the main, urea-forming reaction, a consecutive aminolysis between urea amine groups and aspartate esters occurs, leading to the formation of hydantoin rings but also to additional branching and crosslinking. Aminolysis produces ethanol, which consumes the isocyanate groups of the crosslinker, decreasing its functionality. The DBTDL plays a multifaceted role, not only slowing the main NCO–NH reaction, but also enhancing aminolysis and promoting the NCO–OH reaction. A comprehensive theoretical model incorporating these chemical mechanisms and linking their kinetics to a statistical model of network formation, based on the theory of branching processes, has been developed and validated. The model accurately predicts gel critical conversion and time, effectively resolving the gelling paradox. The model thus provides a powerful tool for understanding and controlling PU-ASPE network formation and structure for optimal performance.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10404 - Polymer science

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Polymer

ISSN

0032-3861

e-ISSN

1873-2291

Volume of the periodical

339

Issue of the periodical within the volume

21 November

Country of publishing house

GB - UNITED KINGDOM

Number of pages

28

Pages from-to

129100

UT code for WoS article

001596542600006

EID of the result in the Scopus database

2-s2.0-105018107484