Preparation, characterization, and mechanical/tribological properties of polyamide 11/ T itanium dioxide nanocomposites

In this study, the effects of the surface chemical modification of titanium dioxide (TiO ₂ ) nanoparticles and their addition into polyamide 11 (PA11) on the mechanical, dynamic‐mechanical, and tribological properties of PA11/TiO ₂ nanocomposites were investigated. To improve the interfacial adhesion between the nanoparticles and the polymeric matrix, the surface of TiO ₂ nanoparticles was modified with 3‐aminopropyl trimethoxysilane (ATPMS). Nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and thermogravimetric analysis (TG) were used to evaluate the efficiency of the surface chemical modification of TiO ₂ nanoxide. PA11/TiO ₂ nanocomposites with 2 and 4 wt% of TiO ₂ were prepared in an internal mixer. The interfacial adhesion between the matrix and the TiO ₂ was evaluated by dynamic‐mechanical analysis (DMA), and the dispersion of nanoparticles was analyzed by scanning electron microscopy (SEM). The NMR spectrum of the modified TiO ₂ exhibited peaks in the region between −55 ppm and −70 ppm, indicating disubstituted and trisubstituted chemical structures between alkoxysilano structures and TiO ₂ . Nanocomposites with modified TiO ₂ exhibited the lowest tan δ peak values, which provide evidence that the chemical modification of the TiO ₂ facilitated energy dissipation at the interface of TiO ₂ with the PA11 matrix. Surface modification of the TiO ₂ nanoparticles with ATPMS caused a greater reduction of the mass loss by abrasion when compared with nonmodified PA11/TiO ₂ nanocomposites; this reduction reached approximately 70% in comparison with the mass loss of neat PA11. POLYM. COMPOS., 37:1415–1424, 2016. © 2014 Society of Plastics Engineers