Journal Article

PreJuSER-10520

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Segmental and normal mode relaxation of poly(alkylene oxide)s studied by dielectric spectroscopy and rheology

Gerstl, C.FZJ* ; Schneider, G. J.FZJ* ; Pyckhout-Hintzen, W.FZJ* ; Allgaier, J.FZJ* ; Richter, D.FZJ* ; Alegria, A. ; Colmenero, J.

2010
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/ma100384j

Abstract: A series of poly(alkylene oxide)s (PAO's) with different lengths of the side chains and two different molecular weights were studied by means of differential scanning calorimetry, dielectric spectroscopy (BDS), and rheology. The glass transition temperatures are almost independent of molar mass and the length of the side chains, which is also reflected by the dielectric a-relaxation, which depends only slightly on the different samples. However, the corresponding maxima in the dielectric loss of the samples with longer side chains show a shoulder at high frequencies with a temperature-dependent shape. The shape of the normal mode changes slightly with the molar mass and the length of the side chain. The normal mode relaxation times show a molar-mass-dependent behavior indicating a significant increase of the entanglement molecular weight M-e with increasing length of the side group. A Rouse mode analysis incorporating the molar mass distribution was performed but could not reproduce the experimental data of the normal mode process completely. The relaxation times obtained by rheology agree well with the dielectric results, and estimates of M-e based on the number of entanglements and on the packing model confirm the values suggested by BDS. A comparison of the estimated chain dimensions with literature data supports the reliability of our calculations.

Keyword(s): J

Note: The present work has been carried out in the frame of the Joint Programme of Activities of the SoftComp Network of Excellence (Contract NMP3-VT-2004-502235) granted under the FP6 by the European Commission. C.G. acknowledges financial support by the International Helmholtz Research School of Biophysics and Soft Matter (IHRS BioSoft). A.A. and J.C. acknowledge the financial support provided by the Donostia International Physics Center (DIPC), the Basque Country Government (Ref. IT-436-07, Depto. Educacion, Universidades e Investigacion), and the Spanish Ministry of Science and Innovation (Grant MAT 2007-63681).

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Contributing Institute(s):

1. Neutronenstreuung (IFF-5)
2. Streumethoden (IFF-4)
3. JCNS (Jülich Centre for Neutron Science JCNS (JCNS) ; JCNS)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Appears in the scientific report 2010

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