FUNCIONALIZAÇÃO DE NANOLÂMINAS DE ÓXIDO DE GRAFENO POR MEIO DE ÁCIDO OXÁLICO E DOPADAS COM CÁLCIO PARA APLICAÇÃO EM ARGAMASSAS DE CIMENTO PORTLAND – PROPRIEDADES FÍSICAS E MECÂNICAS

Abstract

Several studies have used graphene oxide as an additive to improve the mechanical properties of cementitious compounds, as well as have sought improvements to the nanomaterial itself through structural modifications to its surface. Collaborating with this trend, this research aims to synthesize graphene oxide, treat it chemically with oxalic acid and dope it with calcium for later addition in Portland cement mortars in 0.03% of the cement mass. To compare the benefits found by this procedure, three compositions were made: reference samples (without additions), with addition of graphene oxide, and with functionalized and doped graphene oxide. They were evaluated by means of mechanical tests of compressive and tensile strength in bending, water absorption and dimensional variation. For all the properties studied, comparing the three compositions, there was success in the chemical syntheses, with this, the best results were obtained for the samples doped with calcium, with gains of 15.93% and 13.91% in the compression resistance, at 7 days and 28 days, respectively, and for tensile strength at bending 15.89% and 27.14%, at 7 days and 28 days, respectively. For the microstructure, it was noticed that there was an improvement in the refinement of the pores, generating a compaction of the matrix, thus, it is verified that the proposal became efficient in the improvement of the properties of mechanical resistance.