Crystallization kinetics and polymorphism in aromatic polyketones (PEKEKK) with different molecular weight
Simultaneous wide and small X-ray scattering (WAXS and SAXS) real time experiments using sychrotron radiation were performed to investigate poly-aryl(ether ketone ether ketone ketone) (PEKEKK) samples with different molecular weights obtained by precipitation polycondensation. Isothermal melt crysta...
| Autores: | , , , , |
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| Formato: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 1998 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/81022 |
| Acesso em linha: | http://hdl.handle.net/10261/81022 |
| Access Level: | acceso abierto |
| Resumo: | Simultaneous wide and small X-ray scattering (WAXS and SAXS) real time experiments using sychrotron radiation were performed to investigate poly-aryl(ether ketone ether ketone ketone) (PEKEKK) samples with different molecular weights obtained by precipitation polycondensation. Isothermal melt crystallization experiments, using two crystallization temperatures, Tc (differing by 10 °C) for each polymer grade were carried out. The phase transition temperature from polymorphic form II to form I was investigated in the samples as obtained. The variation of the index of crystallinity during heating was shown to depend on molecular weight. The index of crystallinity and X-ray long period values of the isothermal melt-crystallized samples observed at Tc and then at room temperature depend on the Tc values. For the lowest viscosity sample the microstructure is also molecular weight dependent Avrami analysis of the 110(I) reflection leads to the conclusion that a similar crystallization mechanism takes place for the samples investigated.© 1998 American Chemical Society |
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