The availability of raw materials obtained from natural resources in Brazil has motivated their use in the development of more sustainable technologies to obtain novel materials. In this regard, the combination of renewable high density polyethylene (HDPE), obtained from ethanol produced from sugarcane, with residues generated from the production of sponge-gourds, which are generally burnt, was investigated. The residues were characterized according to their moisture, lignin, soluble extractives, ash contents and density, and thermogravimetric analysis was also carried out. The milled waste material was then blended (10-40%wt/wt) with renewable HDPE by extrusion. Specimens were injection-molded for the assessment of properties such as tensile, flexural and Izod impact strengths. The morphological and thermal properties were also investigated. The results show that the addition of the waste material affected all of the properties studied, which were similar to those reported in the literature for composites produced with HDPE obtained from a fossil source. It was found that the sponge-gourd waste has good potential for application as a cellulosic filler, aimed at providing a totally renewable composite with improved tensile modulus and tensile and flexural strength properties compared with the pure renewable HDPE, without altering the thermal properties.

agrofiber residue, sponge-gourds, bio-based HDPE, composites, renewable materials.