Compósitos de nanofibrilas de celulose de bagaço de cana-de-açúcar e nanopartículas lamelares: caracterização de dispersões, filmes e filamentos

Abstract

Cellulosic materials have great importance for industry and scientific research due to their availability, thermomechanical properties, biocompatible aspects and advantages for circular economy strategies and prioritization of renewable sourced materials. The ability of nanofibrillated cellulose to suspend inorganic materials in water sheds light to its potential to produce sensors, flexible optoelectronics and nanostructured films with high value. As a natural material with different sourcing possibilities, there are several methods for isolating and processing cellulose, which determine the morphological and mechanical properties of the material. With this in mind, this intended to respond to some hypotheses: (i) that the processing parameter (number of microfluidization cycles) for the production of cellulosic dispersions would affect their morphology; (ii) that the presence of inorganic particles would affect the rheological behavior of the dispersions; (iii) that the film production method would be able to induce orientation in the material; (iv) that using different shear rates in the production of filaments would change the level of orientation in the material. Thus, the doctoral thesis project consisted of the development of polymeric composites of nanocellulose with different concentrations and types of lamellar nanoparticles: graphite, graphene oxide and lamellar clay. In addition to obtaining a good dispersion of nanoparticles in the matrix, this work also aimed to prepare films and structured filaments, in which the nanocellulose fibrils and lamellar nanoparticles present preferential orientation. The nanostructured systems were characterized by rheological and mechanical testing and morphological analysis. These results were correlated to the microstructural characteristics of their respective dispersions.