Nanocristais de celulose provenientes de fibras amazônicas com potencial aplicação na produção de nanocompósitos

Abstract

Among all the natural polymers, we can highlight the use of cellulose, a mutable and profuse biopolymer in nature, which has enormous chemical variability due to the functionalization of its various hydroxyl groups. It can be presented in form of fibers, microfibrils and nanocrystals. Cellulose nanocrystals have become objects of study in nanocomposites due to their biodegradability, low thermal expansion coefficient, optical anisotropy, high elastic modulus (similar to Kevlar), high aspect ratio and high surface area. This project aims to determine the chemical composition of fibers from the Amazon, namely Jute (Corchorus capsularis L.), Caesarweed (Urena lobata L.) and Surucucumira (Spathelia excelsa (Krause) Cowan & Brizicky [sin. Sohnroyia excelsa K.]), obtaining cellulose nanocrystals from the acid hydrolysis of α-cellulose fibers and analysis of a potential application in the production of nanocomposites. The characterizations of all compounds obtained were made by thermogravimetry (showing the increase in the thermal stability of the fibers), X-Ray Diffraction (showing the increase in crystallinity) and FTIR (showing the reduction of undesirable groups for the present study). The morphology of fibers and nanocrystals were evaluated using SEM (showing fiber modification) and AFM (showing nanocrystals) techniques, respectively. The obtained nanocrystals had an average length of 80.5nm (Jute), 80.9nm (Caesarweed) and 61.5nm (Surucucumira) and an average diameter of 4.9nm, 5.8nm and 4.8nm, respectively.