Two chitosan polymers with different deacetylation degree and molecular weight were subjected to graft- ing reactions with the aim to enhance the properties of these bio-based materials. Specifically, n-butyl acrylate in different proportions was grafted onto two different deacetylation degree (DD%) chitosan using radical initiation in a surfactant free emulsion system. Infrared spectroscopy was used to confirm grafting and products grafting percentage and efficiency were evaluated against acrylate/chitosan ratio and DD%. Thermal and structural properties and the behavior against water of the raw and grafted biopolymers were studied using several experimental techniques: differential scanning calorimetry, transmission electron microscopy, dynamic light scattering, water swelling, contact angle and positron annihilation lifetime spectroscopy. The influence of the grafting process on the morphological and physicochemical properties of the prepared natural/synthetic hybrid materials is discussed.Fil: Anbinder, Pablo. IFIMAT (Instituto de Física de Materiales Tandil). UNCPBA (Universidad del Centro de la Provincia de Buenos Aires). CIFICEN (UNCPBA-CICPBA-CONICET); ArgentinaFil: Macchi, Carlos. IFIMAT (Instituto de Física de Materiales Tandil). UNCPBA (Universidad del Centro de la Provincia de Buenos Aires). CIFICEN (UNCPBA-CICPBA-CONICET); ArgentinaFil: Amalvy, Javier. UNLP (Universidad Nacional de La Plata). INIFTA (Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas). CONICET. CIDEPINT (Centro de Investigación y Desarrollo en Tecnología de Pinturas) CONICET/CICPBA. UTN (Universidad Tecnológica Nacional). CITEMA (Centro de Investigación y Desarrollo en Ciencia y Tecnología de Materiales); ArgentinaFil: Somoza, Alberto. IFIMAT (Instituto de Física de Materiales Tandil). UNCPBA (Universidad del Centro de la Provincia de Buenos Aires). CIFICEN (UNCPBA-CICPBA-CONICET); ArgentinaPeer Reviewed