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Methyl dynamics and β-relaxation in polyisobutylene: Comparison between experiment and molecular dynamics simulations

TitoloMethyl dynamics and β-relaxation in polyisobutylene: Comparison between experiment and molecular dynamics simulations
Tipo di pubblicazioneArticolo su Rivista peer-reviewed
Anno di Pubblicazione2002
AutoriKaratasos, K., Ryckaert J.-P., Ricciardi Rosa, and Lauprêtre F.
RivistaMacromolecules
Volume35
Paginazione1451-1462
ISSN00249297
Parole chiaveCharacterization, Computer simulation, Dielectric relaxation spectroscopy, Glass transition, molecular dynamics, neutron scattering, Nuclear magnetic resonance spectroscopy, Organic polymers, Polyisobutylene, Relaxation processes, Spectroscopy, Temperature
Abstract

Molecular dynamics simulations were employed in bulk polyisobutylene, to provide a detailed characterization of the methyl dynamics and to examine its relation to the β-relaxation as described by different experimental techniques. The simulation results were compared to new 13C NMR measurements probing methyl motion at temperatures above the glass transition, as well as to lower temperature literature NMR data. It was found that the 13C NMR results, and those for the β-relaxation reported by dielectric relaxation spectroscopy and neutron scattering experiments, can be interpreted on a common basis through a coupling mechanism between methyl rotation and a recently described fast relaxation motion associated with the chain backbone. In addition, a molecular mechanism for the description of the dielectric β-process observed in polyisobutylene is proposed, and investigated by simulations.

Note

cited By 21

URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-0037065905&doi=10.1021%2fma011290m&partnerID=40&md5=784013c3188b51bcb6952d21d5a484d9
DOI10.1021/ma011290m
Citation KeyKaratasos20021451