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Oligómeros y polímeros de caprolactona definidos molecularmente: síntesis y caracterización
Kenichi Takizawa1, Chuanbing Tang, Craig J Hawker
1Materials Research Laboratory and Department of Materials, University of California, Santa Barbara, California 93106, USA.
Journal of the American Chemical Society
|January 15, 2008
Resumen
Los investigadores sintetizaron polímeros de epsilon-caprolactona definidos con precisión hasta el 64-mer utilizando una estrategia de crecimiento exponencial eficiente. Este método produce polímeros bien caracterizados, revelando un claro vínculo entre la estructura molecular y las propiedades físicas.
Área de la Ciencia:
- Química de Polímeros La Química de Polímeros es la química de los polímeros.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- La síntesis controlada de polímeros con pesos moleculares definidos es crucial para comprender las relaciones estructura-propiedad.
- Los polímeros de epsilon-caprolactona se utilizan ampliamente, pero el control preciso de la longitud del oligómero / polímero ha sido un desafío.
Objetivo del estudio:
- Desarrollar una síntesis escalable para oligómeros y polímeros molecularmente definidos de epsilon-caprolactona.
- Investigar las relaciones estructura-propiedad de estas macromoléculas definidas con precisión.
Principales métodos:
- Utilizó una estrategia de crecimiento exponencial con grupos de protección ortogonales (éter TBDMS y éster Bn).
- Empleado 1,3-diciclohexilcarbodiimida (DCC) para reacciones de acoplamiento eficientes.
- Se han caracterizado los materiales sintetizados utilizando espectrometría de masas, SEC, IR, RMN, TGA, DSC, AFM y SAXS.
Principales resultados:
- Se han sintetizado con éxito oligómeros y polímeros monodispersos de epsilon-caprolactona hasta 64 mer en gramos.
- Se obtienen altos rendimientos (>80-95%) en reacciones de acoplamiento y rendimientos cuantitativos en etapas de desprotección.
- Demostró una clara relación estructura-propiedad correlacionada con el número de unidades repetidas.
Conclusiones:
- La estrategia sintética desarrollada permite el control preciso de la longitud de la cadena de polímero epsilon-caprolactona.
- El estudio establece una clara correlación entre la definición molecular de oligómeros/polímeros y sus propiedades físicas.
- Se observaron diferencias significativas en las propiedades en comparación con el polímero madre poli (caprolactona).
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