On the β relaxations in poly(butadiene) and poly(styrene-butadiene) rubbers. (2nd April 2019)

• Record Type: Journal Article
• Authors: Souillard, Chloé; Chazeau, Laurent; Cavaillé, Jean-Yves; Brun, Sébastien; Schach, Regis
• Is Part Of: Polymer. Volume 168(2019)
• Page Start: 236
• Page End: 245
• Publication Date: 2019-04-02
• Subjects: Mechanical spectrometry -- Dielectric spectrometry -- Beta relaxation -- Styrene butadiene copolymer; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2019.02.016
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The influence of the chemical microstructure on the secondary mechanical relaxations of PB and SBR has been studied by varying the content of vinyl, cis, trans butadiene and styrene groups. Two relaxational mechanisms are involved in their β mechanical relaxations with two distinct activation energies. The fitting by the summation of two Havriliak Negami functions of the experimental isochronal and isothermal curves prove that the vinyl groups are responsible for the contribution of the High Temperature part of the β-relaxation, whereas the butadiene 1, 4 groups, cis and trans are at the origin of the low temperature part of this relaxation. Moreover, the intensity of the relaxation associated to each monomer appears to be proportional to their volume (and molar) fraction. Given the random characteristics of the studied copolymer, this suggests that the involved mechanisms are localized at the level of only one monomer unit. Graphical abstract: Image 1 Highlights: 2 mechanisms are involved in the β mechanical relaxations of PB and SBR. Vinyls are at the origin of the High Temperature part of this relaxation. Low Temperature part is due to the butadiene 1, 4 - cis and trans -monomers. Intensity of each mechanism is proportional to the vol. fraction of the monomer. The involved mechanisms are localized at the level of only one monomer unit.