Materials Science and Engineering A 528 (2011) 2820–2830 Contents lists available at ScienceDirect Materials Science and Engineering A journal homepage: www.elsevier.com/locate/msea Effect of organoclay platelets on morphology and properties of LLDPE/EMA blends J.S. Borah a , N. Karak b , T.K. Chaki a,∗ a Rubber Technology Center, Indian Institute of Technology, Kharagpur, West Bengal 721302, India b Department of Chemical Sciences, Tezpur University, Tezpur 784028, India article info Article history: Received 4 November 2010 Received in revised form 9 December 2010 Accepted 16 December 2010 Available online 23 December 2010 Keywords: Polymer blends Mechanical properties Morphology Nanocomposites Dynamic mechanical analysis abstract Blends of linear low density polyethylene (LLDPE) and ethylene-co-methyl acrylate (EMA) and their nanocomposites with two types of modified montmorillonite (organoclay) were explored in order to achieve an improved balance between stiffness and toughness. The nanocomposites were prepared in a HAAKE RHEOMIX at three different mixing sequences. The compression molded nanocomposites were utilized to evaluate the morphology and the properties like mechanical, dynamic mechanical and thermal. The results reveal that the morphology and the properties of the nanocomposites are dependent on the blending sequence as well as the type of nanoclay used. The addition of organoclay slightly increases the tensile modulus for all the nanocomposites. On the other hand, a drastic improvement of the impact strength was observed when the organoclay located at the dispersed EMA phase. The effects of clay concentration on the properties of the nanocomposites were also studied. The optimum dispersion as well as property was found for the nanocomposite at 5 wt% of the nano clay. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Blending of two or more polymers is an effective way for developing new materials with useful combinations of properties, not available in a single polymer. Blends of rubber and plastic known as thermoplastic elastomer is an example for polymer blend with toughness more than the neat polymers [1–6]. To widen the diversity of available polymers, another well-known approach is to modify their technical properties by the addition of fillers. In recent years, polymeric materials filled with nanoscale platelets derived from layered silicates, have been gradually receiving more attention because the incorporation of such filler into the poly- mer matrices resulted unexpectedly enhanced properties such as tensile modulus, tensile strength, and heat distortion resistance compared to their pristine polymers [7–13]. More recently, the research in polymer nanocomposites has derived towards the com- bination of the techniques of blending and clay addition to form polymer/polymer/clay ternary materials where often one of the polymer components is a rubber. Polymer blend nanocomposite provides a new material, which has combined properties of poly- mer blend and merit of polymer nanocomposite originating from the nano reinforcement. These materials have various advantages that include their reduced cost, improved mechanical high impact as well as high modulus, thermal, and barrier properties [14–21]. However, there is much to be learned about the mechanisms by ∗ Corresponding author. Tel.: +91 3222283182; fax: +91 3222282292. E-mail address: tapan@rtc.iitkgp.ernet.in (T.K. Chaki). which the clay platelets influence the morphology and mechanical properties of such blends. In a ternary system, in which two of the components are polymers and one is clay, different factors influence the final mor- phology of the nanocomposite, such as the concentration of each component, compatibility between polymers and interaction of the clay with one or both the polymers during melt mixing. It is possible that the method of incorporation of the three differ- ent polarity components into the mixing chamber may affect the intrinsic molecular interactions of the system and, consequently, the final material performance. Recent studies show that presence of organoclay in the continuous phase reduces the domain size of the dispersed phase. This is probably due to the reduction of the coalescence rate of the dispersed phase and/or a compatibilizing effect of the organoclay at the interface between the two phases with perhaps some contribution from the increased melt viscosity of the matrix. Conversely, when the organoclay is located in the dis- persed phase, there often appears to be an increase in the dispersed phase domain size [22–28]. As a consequence of modification of blend morphology, due to the incorporation of organoclay, the mechanical properties are also altered. Dasari et al. [29] studied the effect of blending sequence on the morphology and mechanical properties of Nylon 66/organoclay/SEBS-g-MA terniary nanocomposite and reported that addition of organoclay into the blends leads to higher stiffness and lower toughness than the pristine system and the best balanced is achieved when the organoclay is located in the continuous phase. Li et al. [16] also observed similar kind of behavior for PBT/EVA-g- MA/organoclay nanocomposite. On the other hand, Lee et al. [17] 0921-5093/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.msea.2010.12.067