Avaliação tribológica de óleo vegetal de palma com nanopartículas de cobre e nanotubos de carbono

Abstract

This study aimed to investigate biolubricants with potential application as lubricating oil and as a friction and wear reducer. Its composition contains carbon nanotube nanoparticles (CNT) and copper nanoparticles (NCu) at a concentration of 0.5% suspended in palm vegetable oil (dendê) chemically modified via amidation and esterification. Fourier transform infrared absorbance spectroscopy - FTIR was performed to evaluate the chemical modification of the oil. Thermogravimetric analysis - TGA/DTG was performed to characterize the initial and final temperatures of thermal degradation. An SRV-4® tribometer with controlled conditions and parameters was used to measure the coefficient of friction. Material removal and surface wear mechanisms were determined by scanning electron microscopy (SEM/EDS) and non-contact 3D optical profilometry. With the chemical modification, there was a reduction in the values of the initial degradation temperatures of the butyl and amide-based samples, with only the methyl-based sample showing greater thermal stability than the raw sample. The lowest coefficient of friction (COF) obtained was that of the methyl sample without nanoparticles. The highest COF obtained was that of the amide sample with NPCu. The SEM identified that the main wear mechanisms in the bodies were through abrasion, adhesion and plastic deformation. In the profilometry, it was seen that the methyl-based sample without nanoparticles provided a reduction of more than 55% in the volume removed from the body compared to the other samples.