•Titanate nanotubes (TTNT) were modified with 3-aminopropyltriethoxysilane (APTES).•Effects of TTNT sodium content and solvent on APTES grafting efficiency were studied.•Aqueous ethanol was a more efficient reaction medium for functionalization of TTNT.•Within aqueous ethanol TTNT with low sodium content were more efficiently grafted.•Grafting of APTES on TTNT surface occurs through Ti–O–Si primary chemical bonding. One of the major challenges in the development of nanocomposites based on a polymer matrix and highly polar ceramic nanofillers is the lack of the compatibility between these two components. In order to improve the chemical interaction between titanate nanotubes (TTNT) and polymer matrix, such as nylon 11,3-aminopropyltriethoxysilane (APTES) was grafted onto TTNT. The effects of the TTNT chemical composition i.e. sodium content and solvent type on the grafting silane efficiency were thoroughly studied through CHN elemental analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), surface area and zeta potential measurements. The present study brings evidences supporting aqueous ethanol as more efficient reaction medium for TTNT functionalization with APTES, independent of the sodium content of nanotubes, when compared with pure water. It is also worth noting that within aqueous ethanol medium, TTNT with low sodium content are more efficiently grafted than TTNT with high sodium content. Successful APTES grafting decreases concentration of the hydroxyl groups on TTNT surfaces and enables its future application for the fabrication of nylon 11 nanocomposites.