Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Biocomposites from renewable resource and based on cellulose acetate, dioctyl phthalate and short curaua fibers were prepared by large scale extrusion and injection molding and their mechanical, morphological and thermal properties were studied as a function of plasticizer (dioctyl phthalate) and fiber contents, as well as chemical treatment of the fibers: treatment with NaOH solution or extraction with acetone. The chemical treatments of the fibers play an important role on the mechanical and thermal properties, increasing the Young's modulus (up to 50%), the thermal dimensional stability and the thermal conductivity (ca. 100%) and decreasing the impact strength (ca. 50%) of the composites in comparison with plasticized cellulose acetate. Plasticizer and fibers influence the properties of the biocomposites in the opposite way. Thus the properties of complete and functional formulations of biocomposites of cellulose acetate, plasticizer and curaua fibers with potential of applications and produced by a conventional polymer processing such as extrusion and injection molding can be tailored by controlling the amount and the characteristics of the additives. Among semi-empirical models used to describe the mechanical properties, the Cox-Krenchel and ROM mathematical model showed to be more suitable to describe the Young's modulus of the biocomposites. (C) 2013 Elsevier B.V. All rights reserved.52363372Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2010/02098-0, 2010/17804-7]