Carbohydrate Polymers 168 (2017) 182–190 Contents lists available at ScienceDirect Carbohydrate Polymers j ourna l ho me pa g e: www.elsevier.com/locate/carbpol Conducting cellulose/TiO 2 composites by in situ polymerization of pyrrole Amany M. ElNahrawy a , Ahmed A. Haroun b , Imad Hamadneh c , Ammar H. Al-Dujaili d , Samir kamel e,∗ a Department of Solid State, Physics Division, National Research Centre, 33 El Bohouth st. (former El tahrir st.), P.O. 12622, Dokki, Giza, Egypt b Chemical Industrial Research Division, National Research Centre, 33 El Bohouth st. (former El tahrir st.), P.O. 12622, Dokki, Giza, Egypt c Chemistry Department, Faculty of Science, University of Jordan, 11942 Amman, Jordan d Hamdi Mango Center for Scientific Research, University of Jordan, 11942 Amman, Jordan e Cellulose and Paper Department, National Research Centre, 33 El Bohouth st. (former El tahrir st.), P.O. 12622, Dokki, Giza, Egypt a r t i c l e i n f o Article history: Received 29 November 2016 Received in revised form 19 March 2017 Accepted 20 March 2017 Available online 21 March 2017 Keywords: Cellulose Polypyrrole Nano-composite TiO2-nanoparticles Dielectric properties a b s t r a c t Cellulose/polypyrrole and cellulose/polypyrrole-TiO 2 composites were prepared via in situ oxidative chemical polymerization of pyrrole using FeCl 3 as oxidant. The concentration effect of pyrrole on the structure and properties of prepared matrix has been investigated. Furthermore, the structure of the prepared materials was characterized using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Thermal gravimetrical analysis (TGA). The results exhibited that the addition of cellulose and TiO 2 increase the thermal stability of the polypyrrole sys- tem. Moreover, dielectric properties of the obtained composites were studied over frequency range from 42 Hz to 5 MHz. The electrical measurements including dielectric constant,  ′ (), dielectric loss,  ′′ (), loss tangent, tan  and ac conductivity, ac were carried. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Conducting polymers are promising materials that possess unique properties which allow them to be used in a wide vari- ety of applications (Mihranyan, Garcia, & Stromme, 2008). In recent years, chemical oxidative polymerization has been success- fully developed to produce several interesting conducting-polymer composite based on cellulosic materials and conducting poly- mers (Youssef, Kamel, El-Sakhawy, & El Samahy, 2012; Youssef et al., 2016). The combination of natural materials like cellulose with electronic elements to form multifunctional devices has been the subject of intense scientific research. Significant efforts have been carried out to design cellulose-based flexible supercapaci- tor electrodes through the chemical polymerization of conductive polymers on a cellulose pulp suspension. Polypyrrole, which is one of the most prominent types of conjugated polymers, is a promis- ing conducting polymer in electronics, biological, and medical areas due to its straightforward polymerization, environmental stability, and high electrical conductivity that can be controlled by chang- ∗ Corresponding author. E-mail address: samirki@yahoo.com (S. kamel). ing the doping degree (Ferenets & Harlin, 2007). So it has been performed in a number of applications, such as sensors, superca- pacitors, batteries, microwave shielding and corrosion protection; because it has good environmental stability, ease in synthesis, and characteristic surface charge (Cho et al., 2005). Also, it can be used as conducting filler in insulating polymer matrices during preparation of electrically conducting composites (Amparat, Artita, Walaiporn, & Sirisart, 2008). Building on to the extensive work directed for the development of polymeric composites modified with spherical nanoparticles, the assembly of shape-controlled nanostructure has recently been gaining importance, both for fundamental scientific research and technological applications (Skotheim & Reynolds, 2007). Organic- inorganic composites are multiphase materials obtained through the combination of various materials in order to attain new proper- ties (Amany, Yong, & Ahmed, 2016). So, composites of conducting polymers with noble metals have beneficial properties, like ionic and electrical conductivity, optical activity, flexibility, and capac- itive properties which make them useful in many technological applications. In most cases the poor processability due to the insol- ubility and infusibility of the conducting polymers limits their use in practical applications (Skotheim & Reynolds, 2007). To overcome this problem, the conducting polymers can be incorporated by http://dx.doi.org/10.1016/j.carbpol.2017.03.066 0144-8617/© 2017 Elsevier Ltd. All rights reserved.