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

Kód výsledku v 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>

Nalezeny alternativní kódy

RIV/00216208:11320/25:10508433

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

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

Název periodika

Polymer

ISSN

0032-3861

e-ISSN

1873-2291

Svazek periodika

339

Číslo periodika v rámci svazku

21 November

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

28

Strana od-do

129100

Kód UT WoS článku

001596542600006

EID výsledku v databázi Scopus

2-s2.0-105018107484