CONICET | Buscador de Institutos y Recursos Humanos

The structure of the natural fiber consist on cellulose, which awards the mechanical properties of the complete natural fiber, ordered in micro-fibrils enclosed by the other two main components: hemicellulose and lignin [1]. There are a great number of potential uses of cellulose within different industries. On this field, cellulose micro-fibrils production from agro-resources has become really significant. It generally involves fibers treatment with alkalis or bisulphites to separate the lignin and to extract the hemicelluloses [2]. As well as these microfibrils, there exist nanofibers (composed by cellulose) with diameters of 5-50 nm and lengths of several millimeters conformed by nanocrystalline domains and amorphous regions [3]. A controlled acid hydrolysis can separate both regions driving to crystalline domains with an elastic modulus of 150 GPa, which is higher than that of the S-glass (85 GPa) and Aramid fibers (65 GPa) [4]. Because of the good mechanical properties, nanocellulose has generated a great deal of interest as a source of nanometer-sized reinforcement. In the last years these fibers also attracted much attention due to environmental concerns especially as the reinforcement of bio-degradable polymers to produce fully bio-degradable nano-composites with enhanced mechanical properties [5-7]. In this work the feasibility of extracting nanocellulose from cotton, sisal and flax fibers, corn stover and rice husk by means of usual chemical procedures such as acid hydrolysis, chlorination, alkaline extraction, and bleaching was analyzed. The chemical composition, thermal stability, crystallinity and morphology of the original fibers and final products were characterized by means of Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM) and Atomic Force Microscopy (AFM), respectively.