Comparison between irradiated HDPE/piassava fiber/nanoclay and HDPE/piassava fiber/nanoclay/PP blend Thiago L. S. Souza¹, Beatriz R. Nogueira¹, Anne C. Chinellato², Francisco R. V. Díaz³, Esperidiana A. B. Moura¹* ¹Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242, zip code 05508-000, São Paulo, SP, Brazil ²Federal University of ABC, UFABC, R. Santa Adélia 166, zip code 09210-170, Santo André, SP, Brazil ³Metallurgical and Materials Engineering Department, Polytechnic School, University of São Paulo, Brazil * Corresponding Autor: Tel. (+55) 11 31339883, e-mail: eabmoura@ipen.br Abstract In the present work, the changes in physicochemical, morphological and thermal properties of HDPE/Piassava fiber/nanoclay and HDPE/Piassava fiber/nanoclay/PP blend electron-beam irradiated were evaluated. The samples were irradiated with 100 kGy using a 1.5 MeV electron beam accelerator, at room temperature, in presence of air. The irradiated and non-irradiated samples were submitted to thermo-mechanical tests, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and the correlation between their properties was discussed. The results showed that the incorporation of Piassava (Attalea funifera Mart) fiber and nanoclay followed by electron-beam irradiation represented a significant gain (p < 0.05) in thermo-mechanical properties, changes in surface morphology and reduction in MFI. After irradiation, the nanocomposite showed a gain in the degree of cross-linking, and a better interfacial adhesion between fiber, nanoclay and HDPE. In addition, the HDPE/Piassava fiber/nanoclay/PP blend presented better properties behavior than HDPE/Piassava fiber/nanoclay. In conclusion, based on these results, it may be claimed that incorporation of piassava fiber in small size particles and nanoclay followed by electron-beam irradiation effectively improved the properties of HDPE and led to the obtaining of a HDPE/Piassava fiber/nanoclay/PP blend with superior properties for several industrial applications. Keywords: nanoclay, nanocomposites, piassava fiber, polymer-nanocomposite, electron-beam irradiation, HDPE/nanoclay 1. Introduction Lately, many researchers have experimented with the addition of polymer fibers in order to modify and improve their properties, which has shown positive results by the obtaining of end products with better performance than the original thermoplastic (Neto, 2006). Basically, the thermoplastic matrices available, such as polypropylene (PP) and polyethylene (PE) show the most potential benefits when combined with vegetal fibers to make composites for industrial applications (Bonelli, 2005; Joseph, 1999; Santos, 2003). However, both thermoplastic and thermoset materials can be reinforced with