English   español  
Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/21840
Compartir / Impacto:
Add this article to your Mendeley library MendeleyBASE
Citado 0 veces en Web of Knowledge®  |  Ver citas en Google académico
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL

Heterogeneous structure of poly(vinyl chloride) as the origin of anomalous dynamical behavior

AutorArbe, Arantxa ; Moral, A.; Alegría, Ángel ; Colmenero de León, Juan ; Richter, Dieter; Farago, B.; Frick, Bernhard
Fecha de publicación15-jul-2002
EditorAmerican Institute of Physics
CitaciónJournal of Chemical Physics 117(3): 1336 (2002)
ResumenWe have investigated the thermal evolution of the structure and the dynamics of poly(vinyl chloride) (PVC) in a wide temperature range. Corroborating earlier findings, small angle neutron scattering revealed the presence of structural heterogeneities. On the other hand, the single chain form factor corresponds to that of Gaussian chains. Gradually with increasing temperature the system becomes homogeneous. A simple description of the heterogeneities in terms of microcrystallites is forwarded. The dynamical behavior of PVC has been investigated combining broadband dielectric spectroscopy (DS) with coherent and incoherent neutron scattering. In a wide temperature range broadband DS facilitated a precise determination of the dynamic response related to the segmental relaxation. Close to the glass transition temperature the line shape strongly deviates from the usual Kohlrausch–Williams–Watts functional form of common glassforming systems. Moreover, the characteristic relaxation time observed by incoherent scattering displays an anomalous dependence on momentum transfer indicating the possible existence of heterogeneities in the sample. Based on the structural and dynamical results, a model is proposed, that considers the coexistence of regions with different dynamical properties leading to a distribution of characteristic relaxation times. The model accounts for the experimental observations, assuming for all regions the same functional form for the -relaxation. It may be univocally determined from the coherent scattering data at the first static structure peak. The distribution of relaxation times found is compatible with the distribution of only one variable, the glass transition temperature.
Descripción15 pages, 15 figures, 2 tables.
Versión del editorhttp://dx.doi.org/10.1063/1.1485283
Aparece en las colecciones: (CFM) Artículos
Ficheros en este ítem:
Fichero Descripción Tamaño Formato  
GetPDFServlet.pdf232,18 kBAdobe PDFVista previa
Mostrar el registro completo

NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.