Technical Report Evaluation of clay hybrid nanocomposites of different chain length as reinforcing agent for natural and synthetic rubbers A.A. Yehia a , A.M. Akelah b , A. Rehab b , S.H. El-Sabbagh a , D.E. El Nashar a,⇑ , A.A. Koriem a a Dept. of Polymer & Pigments, National Research Center, Egypt b Chemistry Dept., Tanta University, Egypt article info Article history: Received 20 February 2011 Accepted 29 June 2011 Available online 6 July 2011 abstract Polymer nanocomposites are one of the highly discussed research topics in recent time. It has been reported in the present paper the preparation and the properties of different nanoclays based on sodium montmorillonite (bentonite) and some organic amines of varying chain lengths (dodecylamine, hexadec- ylamine and octadecylamine) beside amine-terminated butadiene–acrylonitrile copolymer (ATBN). The hybrid clays have been characterized with the help of Fourier Transform Infrared spectroscopy (FTIR). Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Wide angle X-ray dif- fractions (WXRD), and Thermogravimetric analysis (TGA). X-ray results showed that the intergallery dis- tance of the clay is increased as a result of the intercalation of the amines and ATBN. The nanocomposite clays were incorporated in natural and synthetic rubbers (NR, SBR and NBR). The physico-mechanical properties are greatly improved with loading low concentrations of the nanocomposite clays compared with carbon black. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction The words ‘‘nanocomposites,’’ ‘‘nanomaterials,’’ and ‘‘nanofil- lers’’ are fairly recent, but they were in use from the beginning of this century (for example, carbon black is being used as a reinforc- ing filler in rubbers since 1904) and apparently always existed in nature (in minerals and vegetation) [1]. The three major advanta- ges that nanocomposites have over conventional composites are as follows: (i) lighter weight due to low filler loading, (ii) low cost due to fewer amounts of filler to be used, (iii) Improved properties (such as mechanical, thermal, optical, electrical, barrier, etc.) compared with the conventional composites. Three types of nanocomposites can be distinguished depending upon the number of dimensions of the dispersed particles in the nanometer range [2] as follows: (i) Isodimensional nanofillers result when the three dimensions are in the order of nanometers, such as spherical silica nano- particles obtained by in situ solgel methods [3]. (ii) When two dimensions are in the nanometer scale, while the third is larger, an elongated structure for example, carbon nanotubes [4] or cellulose whiskers [5], which are exten- sively, studied as reinforcing nanofillers yielding materials with exceptional properties. (iii) The third type of nanocomposites is characterized by only one dimension in the nanometer range. Here the filler is in the form of sheets of one to a few nanometer thick to hun- dreds or thousands nanometers long. Clays and layered sili- cates belong to this family and the composites are known as polymer–clay nanocomposites (PCNs) or polymer-layered silicate nanocomposites (PLSNs). The first PLSNs were reported by Blumstein in 1961 [6], but research in the nano- composites field gained momentum only after the Toyota Research Group of Japan reported the development of PA6- clay nanocomposites by the in situ polymerization tech- nique [7]. The work of Vaia et al. [8] made it possible to melt mix polymers with clays without the use of organic solvents and this opened the doors for vigorous research in this field [9]. In practice, there exist three types of composites based upon layered silicates (clays) and these are shown as: (a) conventional composites, where nonswollen layered sili- cates are embedded in a polymer matrix, (b) intercalated and (c) exfoliated layered silicates nanocomposites. Till date, research involving layered silicates of synthetic and natural origin for the property modification of polymers was mostly devoted to thermoplastics [2,10–14] and thermosetting 0261-3069/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.matdes.2011.06.066 ⇑ Corresponding author. Tel.: +20 2 0101648170; fax: +20 2 3334455146. E-mail address: doaaelnashar@yahoo.com (D.E. El Nashar). Materials and Design 33 (2012) 11–19 Contents lists available at ScienceDirect Materials and Design journal homepage: www.elsevier.com/locate/matdes