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Establishment of the synthesis route of furfuryl resin in acidic medium to minimize the exothermy of reaction

ABSTRACT

Poly(furfuryl alcohol) (PFA) is a bioresin obtained from furfuryl alcohol (FA) extracted from renewable sources. This resin, when cured, has excellent characteristics, such as high hardness, chemical stability, and good mechanical resistance, which make its use in different areas viable, especially in the aerospace and bioengineering sectors. However, its use on a large scale is still limited due to the difficult control of its synthesis process since the polycondensation reaction of FA is extremely exothermic. The present work aims to contribute to the area of PFA synthesis, through the study of its obtainment in acidic medium and at low temperature (∼50 ºC), varying the reaction times (1, 2, and 3 h), aiming at greater control of the exothermy of the reaction medium. Fourier transform infrared spectroscopy analyses confirmed the syntheses success, which showed the presence of ketones and structures according to Diels-Alder and the Dunlop and Peters. Viscosity measurements showed low values (230 to 470 mPa.s), which are in agreement with the low molar masses obtained by gel permeation chromatography (M¯w: ∼800 g/mol). These results show that the synthesis conditions used kinetically unfavored the progress of the reaction but avoided exothermic peaks. Thermogravimetric analysis (TGA) of the PFAs cured with p-toluenesulfonic acid (2 and 3%, w/w) showed mass losses since the beginning of the analysis due to the presence of water and low molar mass fractions in the sample. These data agree with the images obtained by scanning electron microscopy, which showed a high volume of pores. Relevant results were observed in the TGA analysis under an inert atmosphere, with high values of carbon yield (50–60%), indicating the potential use of synthesized PFAs in the area of carbon materials.

Keywords
Synthesis; Furfuryl alcohol; Furfuryl resin

Laboratório de Hidrogênio, Coppe - Universidade Federal do Rio de Janeiro, em cooperação com a Associação Brasileira do Hidrogênio, ABH2 Av. Moniz Aragão, 207, 21941-594, Rio de Janeiro, RJ, Brasil, Tel: +55 (21) 3938-8791 - Rio de Janeiro - RJ - Brazil
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