Investigating the Effect of Nanolayered Silicates on Blend Segmental Dynamics and Minor Component Relaxation Behavior in Poly(ethylene oxide)/Poly(methyl methacrylate) Miscible Blends Kazem Jeddi, 1 Nader Taheri Qazvini, 2 Seyed Hassan Jafari, 1 Hossein Ali Khonakdar, 3 Javad Seyfi, 1 Uta Reuter 4 1 School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran 2 School of Chemistry, College of Science, University of Tehran, P.O. Box 14155-6455, Tehran, Iran 3 Iran Polymer and Petrochemical Institute, P.O. Box 14965-115, Tehran, Iran 4 Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, D-01069 Dresden, Germany Correspondence to: N. T. Qazvini (E-mail: ntaheri@khayam.ut.ac.ir) Received 16 January 2010; revised 18 August 2010; accepted 21 September 2010; published online 19 October 2010 DOI: 10.1002/polb.22168 ABSTRACT: Polymer–silicate nanocomposites based on poly (ethylene oxide), PEO, poly(methyl methacrylate), PMMA, and sodium montmorillonite clay were fabricated and characterized to investigate the effect of nanolayered silicates on segmental dynamics of PEO/PMMA blends. X-ray results indicate the for- mation of an exfoliated morphology in the nanocomposites. At low silicate contents, an enhancement in segmental dynamics of blend nanocomposites and also PEO, minor component in blend, is observed at temperature region below blend glass transition. This result can be attributed to the improvement of the confinement effect of rigid PMMA matrix on the PEO chains by introducing a low amount of layered silicates. On the other hand, at high silicate contents, an enhancement in seg- mental dynamics of blend nanocomposites and PEO is observed at temperature region above blend glass transition. This behavior could be interpreted based on the reduction of monomeric friction between two polymer components, which can facilitate segmental motions of blend components in nano- composite systems. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 318–326, 2011 KEYWORDS: blends; glass transition; ionic conductivity; nano- composites; PEO/PMMA; PEO/PMMA miscible blends; polymer/ clay nanocomposites; segmental dynamics INTRODUCTION In recent years, there has been a great atti- tude towards polymer blending because of its economical advantages and also because this method facilitates access to new materials with tailor-made properties. The ability to understand and predict the behavior and properties of poly- mer blends has long been the motive for many research works. In this area, investigating the dynamics of polymer blends has been one of the most significant topics. Dynamics in polymer blends, in both segmental and terminal levels, has been a very substantial issue from fundamental point of view as well as technological applications. 1 In the studies on dynamics of miscible polymer blends some novel results have been reported. For example, in spite of thermodynamical miscibility and mixing in molecular levels, generally the dynamics of the two constituents in the blend show dissimilar temperature dependences. 2 Therefore, the two constituents display their own dynamical behavior. This phenomenon which is called dynamic heterogeneity results in a failure of time–temperature superposition principle. 3 Furthermore, for miscible blends, the two components have weak interactions and a large difference in their glass transi- tion temperatures (T g s), thermorheological complexity has been reported. 4–10 Also, a large T g contrast between two con- stituents reveals large mobility differences, and it is likely that two polymers relax separately with considerably differ- ent rates. 11 Composition fluctuations of the system, especially in blends with low interactions, self-concentration effects, coupling between the chains and intrinsic mobility differences between the chains can be considered as the factors impact- ing dynamics in miscible blend systems. 12–15 Poly(ethylene oxide)/poly(methyl methacrylate), PEO/PMMA blend is one of the most studied polymer blends. 16–23 These blend systems show a small negative interaction parameter v. 20 Also, because PEO is a semicrystalline polymer, for blends with PEO more than 20–30% crystallization of this component will occur. 20,21 Because of large difference in T g between the two polymers, 206 K for PEO and 386 K for PMMA, these blend systems V C 2010 Wiley Periodicals, Inc. 318 JOURNAL OF POLYMER SCIENCE: PART B: POLYMER PHYSICS 2011, 49, 318–326 FULL PAPER WWW.POLYMERPHYSICS.ORG