Dielectric and dynamic mechanical study of the mobility of poly(t-butylacrylate) chains in diblock copolymers: polystyrene-b-poly(t-butylacrylate)

Encinar del Pozo, Mario and Guzmán Solís, Eduardo and González Prolongo, Margarita and González Rubio, Ramón and Sandoval, Claudia and González-Nilo, Fernando D. and Gargallo González, Ligia and Radic Foschino, Deodato (2008). Dielectric and dynamic mechanical study of the mobility of poly(t-butylacrylate) chains in diblock copolymers: polystyrene-b-poly(t-butylacrylate). "Polymer", v. 49 (n. 26); pp. 5650-5658. ISSN 0032-3861. https://doi.org/10.1016/j.polymer.2008.10.023.

Description

Title: Dielectric and dynamic mechanical study of the mobility of poly(t-butylacrylate) chains in diblock copolymers: polystyrene-b-poly(t-butylacrylate)
Author/s:
  • Encinar del Pozo, Mario
  • Guzmán Solís, Eduardo
  • González Prolongo, Margarita
  • González Rubio, Ramón
  • Sandoval, Claudia
  • González-Nilo, Fernando D.
  • Gargallo González, Ligia
  • Radic Foschino, Deodato
Item Type: Article
Título de Revista/Publicación: Polymer
Date: December 2008
ISSN: 0032-3861
Volume: 49
Subjects:
Freetext Keywords: Dielectric relaxation; block copolymers; glass transition
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Materiales y Producción Aeroespacial
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

A calorimetric, dielectric and dynamic-mechanical study of the dynamics of the poly(t-butyl acrylate) (PtBa) chains has been carried out in a PtBa homopolymer and two polystyrene (PS)-b-PtBa block copolymers with different PtBa chain lengths. The DSC results show that the size of the cooperative rearranging regions is similar in the homopolymers and the copolymers, both for the PtBa rich- and the PS-rich regions. Therefore, no significant contributions are found arising from composition fluctuations in the copolymers. The relaxation map obtained from dielectric relaxation indicates that there are no differences in the temperature dependence of the α-relaxation of the PtBa block in the three samples studied. However, there are larger differences for the values obtained from DMTA experiments. Contrary to the α-relaxation, the relaxation map for the β-transition shows that the characteristic times for the PtBa blocks are smaller in the homopolymer than in the copolymers. In principle, these are unexpected results because the β-relaxations have a more local character than the α-ones. The width of the α-relaxation increases with T for all the samples, and it is slightly larger for the copolymers. The intensity of the α-relaxation is larger (between 3 and 4 times) for the homopolymer. Considering the molecular weights of the PtBa blocks, this effect has to be ascribed to the existence of frozen amorphous PtBa due to the existence of the glassy PS domains in the microphase separated copolymers. Molecular Dynamic Simulations (MDSs) for different sequences of the polymers under study were carried out. The conformational analysis was carried out between 1000 and 1700 K. The analysis of the variation of angles 1 and 2 of the ester group of PtBa points out the existence of a correlation between the conformational changes of the side group of the polymer chains and their relaxational behaviour.

More information

Item ID: 2859
DC Identifier: http://oa.upm.es/2859/
OAI Identifier: oai:oa.upm.es:2859
DOI: 10.1016/j.polymer.2008.10.023
Official URL: http://www.elsevier.com/wps/find/journaldescription.cws_home/30466/description#description
Deposited by: Memoria Investigacion
Deposited on: 13 Apr 2010 09:27
Last Modified: 20 Apr 2016 12:29
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