Iranian Polymer Journal

, Volume 22, Issue 8, pp 613–622

Nanoconfined segmental dynamics in miscible polymer blend nanocomposites: the influence of the geometry of nanoparticles

Original Paper

DOI: 10.1007/s13726-013-0160-4

Cite this article as:
Chehrazi, E. & Taheri Qazvini, N. Iran Polym J (2013) 22: 613. doi:10.1007/s13726-013-0160-4

Abstract

The influence of nanoconfinement on segmental relaxation behavior of poly(methyl methacrylate) and poly(styrene-ran-acrylonitrile) miscible blend and its nanocomposites with spherical and layered nanoparticles have been investigated. Dynamic mechanical analysis was employed to examine the effect of geometry of nanoparticles on the temperature dependence and relaxation function breadth of segmental dynamics (α-relaxation) in the glass transition region. The maxima of the loss modulus curves were used to fit to the Vogel–Fulcher–Tamman equation to describe the temperature dependence of the characteristic relaxation times. Furthermore, the Tg-normalized semi-logarithmic Arrhenius plots (fragility plots) were exploited to indicate the changes in cooperative segmental motions across the glass transition. The master curves for relaxation modulus were also constructed for each sample as a function of time using the time–temperature superposition principle. The investigated nanocomposites showed a narrower segmental dispersion in the glass transition region compared to the neat systems. The relaxation modulus master curves were fitted by the Kohlrausch–Williams–Watts (KWW) function. It was observed that the distribution parameter of segmental relaxation time increased with addition of nanoparticles which was correlated with a decrease in fragility index. In addition, the increase of the KWW distribution parameter (βKWW) for spherical silica nanocomposites was less than that for nanocomposites prepared with layered silicates (organoclay).

Keywords

Glass transition Nanoconfinement Nanocomposites Segmental dynamics Polymer blends 

Copyright information

© Iran Polymer and Petrochemical Institute 2013

Authors and Affiliations

  1. 1.Department of Polymer EngineeringAmirkabir University of Technology, Mahshahr BranchMahshahrIran
  2. 2.Polymer Division, School of Chemistry, University College of ScienceUniversity of TehranTehranIran
  3. 3.Biomaterials Research Center (BRC)University of TehranTehranIran

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