Thermal and structural characterization of buriti fibers and their relevance in fabric reinforced composites

Engineering applications involving polymer composites reinforced with natural lignocellulosic fibers (NLFs) have greatly increased in recent decades due to advantages associated not only with favorable composite properties but also fiber sustainability and cost-effectiveness. A search for less common NLFs is currently an endeavor for the development of novel composites with improved properties. In particular, for applications above room temperature, the thermal resistance must be characterize. In the present work composites reinforced with up to 30 vol% fabric made of buriti, a relatively unknown natural fiber from Brazil, with limited reported information, were characterized by thermogravimetric/derivative (TG/DTG) and dynamic mechanical analysis (DMA). Preliminarily, the plain buriti fiber was investigated in terms of X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and TG/DTG analysis. XRD pattern allowed, for the first time, the evaluation of a microfibril angle of 7 degrees and crystallinity index of 63%. FTIR bands for buriti fibers were also obtained with expected results. TG/DTG results indicate for the buriti fiber a limit degradation temperature around 200 degrees C and for the buriti fabric epoxy composites at about 250 degrees C. Dynamic mechanical analysis of composites disclosed similar viscoelastic stiffness values but an increasing glass transition temperature with the amount of buriti fabric. (C) 2019 Published by Elsevier B.V.