Functionalization of Sodium Titanate Nanoribbons with Silanes and their use in the Reinforcement of Epoxy Nanocomposites Miroslav Huskic ´, 1,2 Tamara Holjevac Grguric ´, 3 Polona Umek, 4,5 Ivan Brnardic ´ 3 1 Center of Excellence PoliMaT, Tehnolo  ski Park 24, 1000 Ljubljana, Slovenia 2 National Institute of Chemistry Slovenia, Hajdrihova 19, 1000 Ljubljana, Slovenia 3 University of Zagreb, Faculty of Metallurgy, Aleja narodnih heroja 3, 44103 Sisak, Croatia 4 Jo zef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia 5 Center of Excellence Namaste, Jamova cesta 39, 1000 Ljubljana, Slovenia This paper reports on the surface functionalization of sodium titanate nanoribbons (NaTiNRs) with four different silane coupling agents: 3-(aminopropyl)tri-ethoxysilane, triethoxyoctylsilane, 3-glycidyloxypropyltrimethoxysilane, and 3-aminopropylmethyl diethoxysilane. The functional- ized NaTiNRs were used to prepare epoxy-based nano- composites with three different wt% of nanofillers (1, 2 and 3 wt% per epoxy). The properties of the prepared nano- composites were then compared with the pure epoxy resin. The functionalized NaTiNRs, as well as the epoxy and prepared nanocomposites, were characterized using Fourier-transform infrared spectroscopy, simultaneous dif- ferential scanning calorimetry-thermogravimetric analysis (DSC-TGA), scanning electron microscopy (SEM), differen- tial scanning calorimetry (DSC), and dynamic mechanical analysis. The SEM results showed that the 2- and 3- functional silanes are not the best choice for the modifica- tion as they glue the NaTiNRs together into clusters. As a consequence, the glass-transition temperatures and the mechanical properties are not strongly influenced by the addition of functionalized NaTiNRs. Nevertheless, the influ- ence of the type of silane can be observed. Furthermore, the thermal stability of the prepared nanocomposites increases with the increased loading of the functionalized NaTiNRs. POLYM. COMPOS., 34:1382–1388, 2013. V C 2013 Society of Plastics Engineers INTRODUCTION Over the past few years alkali titanate nanotubes and nanoribbons have been the subject of intensive research for possible applications in photocatalysis, sensors, and lithium-ion batteries because of their interesting physical properties [1–6]. However, these materials are not only interesting for these already-mentioned applications, but for the preparation of polymer nanocomposites as well. Two main reasons for their use in this field are: (i) their Young modulus, which is comparable to that of carbon nanotubes [7] and (ii) the fact that they can be synthesized in large quantities with high yields. So far, this possibility has not been much investigated. In fact there are only a few publications reporting on the mechanical properties of nanocomposites prepared from sodium titanate nanotubes (NaTiNTs), nanoribbons (NaTiNRs), or their protonated forms (HTiNTs and HTiNRs). For instance, Cheng et al. described the preparation of nanocomposites by the in-situ polymerization of aniline in the presence of HTiNTs [8]. A different approach was used by Byrne et al. [9]: in the first step they functionalized NaTiNTs with allyltriethoxy- silane or propyltriethoxysilane and then, in the next step, nanocomposites of polystyrene (PS) with functionalized NaTiNTs were prepared by depositing a solution of functionalized NaTiNRs and PS in tetrahydrofurane (THF) on a glass surface. The thin, nanocomposite film that was formed by the slow evaporation of THF showed an improvement in the elastic modulus and tensile strength. In contrast, nanocomposites of PS and NaTiNTs and NaTiNRs prepared by extrusion did not exhibit a signifi- cant increase in their elastic modulus [10] because of the low adhesion between the sodium titanate nanostructures and the polymer matrix. The HTiNTs were used to prepare a Nafion membrane nanocomposite. In this case the Correspondence to: Miroslav Huski; e-mail: miro.huskic@ki.si DOI 10.1002/pc.22555 Published online in Wiley Online Library (wileyonlinelibrary.com). V C 2013 Society of Plastics Engineers POLYMER COMPOSITES—2013