Preparação e caracterização de novos materiais híbridos a partir de (3-aminopropil) trimetoxisilano

Abstract

In this work, was investigated the obtaining of new materials from the hydrolysis and acid condensation reactions of (3-aminopropyl) trimethoxysilane, which resulted in the formation of hybrid nanostructures with ammoniums groups and counter ions chloride (POSS-NH3Cl). The nanostructures were subjected to ion exchange procedures for 0.5, 2, 12 and 48 h for the removal of chloride ions. The titrimetric and volumetric results showed that the ion exchange occurred partially. The synthesized particles are predominantly POSS-NH2 cage-shaped structures (T8). After the ion exchange, the nanostructures have ability to selfassembly through electrostatic interactions forming the blackberry-like structures with approximately 100 nm. The POSS-NH2 cluster are formed by primary particles with a size of 1.4nm structured in form of a mass fractal with correlation length () dependent on the ion exchange time. Due to the electrostatic characteristic of the particles was possible obtained hybrid films optically transparent with a high degree of hydrophilicity. POSS-NH2 nanoparticles were used as additive of lubricants of renewable sources (fatty acids) by means of microwave-assisted direct reactions of amidation, without the use of catalysts. The formation of amide bonds were confirmed through the FTIR and 1H NMR techniques, where angular deformation bands in NH in 1550 cm-1 and 1120 cm-1 and the appearance of an enlarged singlet in 6.50 ppm (NH) were observed. The biolubricants was found that an alloy fatty acid molecule with a POSS, but has not yet noticed the existence of agglomerates after amidation, as TEM results of biolubricants. The POSS-NH2 are bonded individually to only one fatty acid molecule, however it was noted the existence of cluster after amidation reactions, as observed in TEM results of the biolubricants. The addition of POSS-NH2 nanoparticles reduced the oxidation rate of the biolubricants and has dependence on the ion exchange time. All the biolubricants showed a Newtonian rheological behavior and the viscosity at 25°C dependent on the amount of particles and not the exchange time. The addition of POSS-NH2, improved the performance of the biolubricants applied on metallic surfaces, since the studied sliding pair showed lower and more stable values of coefficient of friction, as compared to the base oil. Moreover, the biolubricants showed a high load support capacity, which represents the critical load for the scuffing occurrence of the system. The wear resistance of the metallic surfaces changed with the addition of POSS particles in the lubricant oil and with the ionic exchange time adopted for the synthesis of the particles.