Preparation of cellulose nanofibres from diferent sources of cellulose fibres, such as wood, annual plants, agroforetry wastes, secondary fibres. Application of chemical systems to isolate cellulose nanofibres (acid hydrolysis, and catalytic oxidation). Characterization of cellulose nanofibres (whiskers). Use of cellulose whiskers as filler / reinforcement of polymer matrices for the preparation of nanocomposites with special properties. Use of hydrophilic matrices or latex systems. Characterization of the obtained nanocomposites.