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Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in PolyS-Divinylbenzene
Published on: May 20, 2019
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Descifrar los mecanismos autocatalíticos de la polimerización y la transesterificación en los vitrímeros de
Antoine Adjaoud1,2, Benoit Marcolini1, Reiner Dieden1
1Luxembourg Institute of Science and Technology, 5 Avenue des Hauts-Fourneaux, Esch-sur-Alzette L-4362, Luxembourg.
Journal of the American Chemical Society
|May 2, 2024
Resumen
Este estudio revela cómo los catalizadores internos aceleran los intercambios dinámicos en los vitrímeros de benzoxazina. La participación de grupos vecinos y el diseño de catalizadores son clave para mejorar la formación de redes y permitir reacciones de transesterificación eficientes.
Área de la Ciencia:
- Química de los polímeros
- Ciencias de los materiales
- Química orgánica
Sus antecedentes:
- Las redes adaptables covalentes (CAN) utilizan catalizadores internos para el intercambio dinámico.
- Las polibenzoxazinas pueden formar vitrímeros a través de la transesterificación inducida térmicamente.
- Las aminas terciarias actúan como catalizadores internos en estos sistemas.
Objetivo del estudio:
- Investigar las complejidades químicas de la transesterificación en los vitrímeros de benzoxazina.
- Sintetizar y caracterizar moléculas modelo para estudiar los mecanismos de reacción.
- Aclarar el papel de la estructura del catalizador y la proximidad en la cinética de la reacción.
Principales métodos:
- Síntesis de moléculas modelo (ácidos fenólicos y aminoalcoholes).
- Resonancia magnética nuclear (RMN) para elucidación estructural.
- Calorimetría de barrido diferencial (DSC), reología y análisis termogravimétrico junto con cromatografía de gases microcomputada (TGA-μGC) para el análisis de la reacción.
Principales resultados:
- Los grupos alifáticos -OH aceleran la formación de la red.
- La proximidad espacial de los grupos amino e hidroxilo terciarios mejora la tasa de cambio a través de la participación del grupo vecino (NGP).
- La amina terciaria en la benzoxazina exhibe latencia térmica, requiriendo la apertura del anillo para iniciar el intercambio dinámico.
Conclusiones:
- El diseño del catalizador, específicamente el obstáculo estérico y la basicidad de aminas terciarias, es crucial para promover el intercambio dinámico.
- NGP aumenta significativamente las tasas de transesterificación en los vitrímeros de benzoxazina catalizados internamente.
- La comprensión de estos mecanismos permite el desarrollo de redes de polímeros adaptables avanzadas.
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