ORIGINAL PAPER Nanoclay dispersion in a miscible blend: an assessment through rheological analysis Mahdi Ghelichi & Nader Taheri Qazvini & Seyed Hassan Jafari & Hossein Ali Khonakdar & Uta Reuter Received: 25 October 2011 / Accepted: 20 January 2012 # Springer Science+Business Media B.V. 2012 Abstract In this study, miscible polymer blend nanocom- posite of Poly(ethylene oxide)/Poly(methyl methacrylate), (PEO/PMMA), with sodium montmorillonite (Na + -MMT) clay were prepared at a constant concentration of nanopar- ticles via different solution intercalation methods. The re- sultant nanocomposites possess different structure and dispersion of Na + -MMT clays which are assessed through a combination of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The rheology of the neat blend and two different layered silicate nanocomposites were in- vestigated using linear viscoelastic measurements with a parallel plate rheometry at small strain amplitudes. It was found that regardless of the extent of dispersion, the storage and loss modulus increased by incorporating the nanopar- ticles into the matrix of PEO/PMMA. Moreover, at low frequencies the rheological response of the nanocomposite in which layered silicates benefit from a better dispersion becomes relatively invariant with frequency and represents a mediocre solid-like behavior in comparison to the nano- composite in which the nanoparticles are intercalated or agglomerated. Keywords Poly(ethylene oxide)/Poly(methyl methacrylate) . Rheology . Nanoclay . Dispersion . Visco-elastic behavior Introduction Nanostructured materials particularly polymer layered sili- cate nanocomposites (PLSNCs) have recently gained com- mercial and scientific attentions [1, 2]. Different kinds of nanofillers with various treatments were employed to im- prove the physical properties of pure polymers or ordinary composites [3, 4]. These enhanced physical properties are usually in the forms of decreased flammability, improved heat resistance, and increased moduli. Controlling the mi- crostructure of polymer nanocomposites with the aim of achieving desirable properties has been the subject of many studies [5–7]. Three possible structures are usually observed in PLSNCs. The intercalated structure, in which polymer chains are located in the narrow distance of the silicate layers, the exfoliated structure where silicate layers are dispersed in the polymeric matrix, and the immiscible or unmixed structure where polymer chains do not penetrate into the stack of silicate layers. Recently, to prepare polymer nanocomposite, different methods such as melt blending, solvent mixing, and in-situ polymerization were employed. The follow-on rheological and structural properties have always been a focus of many investigations [6, 8–10]. Understanding the relationship be- tween the structure and rheological properties is of para- mount importance in predicting the processing behavior of M. Ghelichi : S. H. Jafari Department of Polymer, School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155–4563, Tehran, Iran N. Taheri Qazvini (*) Department of Polymer, School of Chemistry, College of Science, University of Tehran, P.O. Box 14155–6455, Tehran, Iran e-mail: ntaheri@khayam.ut.ac.ir H. A. Khonakdar Iran Polymer and Petrochemical Institute, P.O. Box 14965–115, Tehran, Iran U. Reuter Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, D-01069 Dresden, Germany J Polym Res (2012) 19:9830 DOI 10.1007/s10965-012-9830-8