Jaroslava Budinski Simendić, et al., Thermal stability and damping properties of polyurethane… Contemporary Materials, V−1 (2014) Page 64 of 68 Brief scientific papers UDK 665.335.5.094.3 doi: 10.7251/COMEN1401064S THERMAL STABILITY AND DAMPING PROPERTIES OF POLYURETHANE HYBRID MATERIAL BASED ON CASTOR OIL Jaroslava Budinski Simendić 1 , Zoran Bjelović 2 , Suzana Samaržija Jovanović 3 , Vojislav Aleksić 2 , Helena Valentova 4 , Katalin Meszaros Szecseny 5 , Ivan Krakovsky 4 1 Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia 2 Faculty of Technology, Zvornik, University of East Sarajevo, Karakaj bb, 75400 Zvornik, B&H 3 Faculty of Natural Science and Mathematics, University of Pristina, Ive Lole Ribara 29, 38220 Kosovska Mitrovica, Serbia 4 Faculty of Natural Science and Mathematics, Charles University, Prague, Czech Republic 4 Faculty of Natural Science and Mathematics, University of Novi Sad, Trg Dositeja Obradovića 3, 21000 Novi Sad Serbia Abstract: This study reports the fabrication of environmentally friendly polyurethane materials using either 2,4-toluene diisocyanate or isophorone diisocyanate, castor oil as a polyol component, and TiO 2 nanoparticles. Samples were prepared with sto- ichiometric balance of reactive groups. Dynamic viscoelastic properties of prepared samples were studied. The ratio of the loss component to the storage component (tanδ) was used as a measure of the material damping properties. The glass transition temperature was determi- ned as a position of the tanδ curve maximum. The temperature range with tanδ > 0.3 was used to evaluate damping capacity of elastomers. Thermal stability of prepared samples was estimated by TGA method. It was assessed that PU based on aliphatic diisocyanate have higher thermal stability. Obtained values of the glass transition temperature and the starting degradation temperature are important for the application window of novel materials. Keywords: Castor oil, polyurethanes, DMA, nanocomposites. 1. INTRODUCTION Polyurethanes (PU) are polymers composed of a chain of organic units joined by carbamate (urethane) links and have enormous diversity of chemical composition, tissue biocompatibility, biodegradability and mechanical properties. Both the isocyanates and polyols used to make polyurethanes contain on average two or more functional groups. These materials are produced in the form of micro- cellular foam seals and gaskets, fibers, durable ela- stomeric wheels and tires, electrical potting compo- unds, coatings, adhesives and auxiliary agents, for wind turbine blades, memory shape materials, acou- stic foams, hard-plastic parts for electronic instru- ments [1–5]. The formation of polyurethanes based on vegetable oils is very complex and thus for indu- strial production it is important to determine the optimal temperature for synthesys and finally to obtain materials with the proper mechanical and thermal properties. Some PU types are very promi- nent damping materials for reduction of noise and prevention of fatigue failure of materials because they can be easy tailored either as thermoplastic ela- stomers or as permanent polymer networks [6–11]. In the case of polyurethane hybrid materials the damping behavior is affected by intramolecular fric- tion and molecular relaxation, friction between polymer chains and filler, and friction between two filler particles [12]. PU with dangling chains in network structure have good energy absorbing pro- perties [13]. The materials based on aliphatic 5- isocyanato-1-(isocyanatomethyl)-1,3,3-trimethyl- cyclohexane (isophorone diisocyanate, IPDI) due to its stable aliphatic structure makes them ideal for producing durable, non-yellowing materials. Isocyanate groups of different reactivity allow selec- tive chemical reactions and application for wood coatings, leather adhesives, network precursors, and powder coatings. The aromatic isocyanates are more * Corresponding author: jarkamer@gmail.com brought to you by CORE View metadata, citation and similar papers at core.ac.uk