High-performance Resveratrol-based Benzoxazine and Epoxy Thermosetting Systems with Siloxane Groups as Flame Retardant Moeities

FORCHETTI CASARINO, AGUSTIN; CASIS, NATALIA; MINEN, JUAN MARTIN; DIANA ESTENOZ; SPONTÓN, MARISA ELISABET

Buenos Aires

Congreso; Actas del WCCE11 - 11th World Congress of Chemical Engineering; 2023

Polybenzoxazines are thermosetting materials constituted by phenolic structures attached by Mannich bridges,obtained from thermally induced ring-opening of 3,4-dihydro-2H-1,3-benzoxazine precursors. Usually, thesemonomers are obtained by reaction between phenols, formaldehyde and primary amines, and they present highflexibility in the molecular design and processability. Different functional groups can be incorporated into the monomerstructures in order to afford materials with targeted properties[1]. In particular, siloxane-based polybenzoxazines havegained prominence due to their excellent thermal resistance, high Tg and significant compatibility with organiccompounds[2]. Therefore, the objective of this work relies on the preparation of novel renewable polybenzoxazineswith siloxane groups in chemical structure in order to obtain high-performance bio-based thermosets. For thispurpose, a novel benzoxazine based on alcoxysilane was synthesized by reaction between resveratrol, 3-(trimethoxysilyl) propylamine and paraformaldehyde in an initial molar ratio 1:3:6 (RES-3aptms). The chemicalstructure was characterized by 1H- and 13C-NMR obtaining high purity. Also, four experimental sol-gel conditions werecarried out to obtain a siloxane-based hybrid precursor [Pr(RES-3aptms)] (Figure 1a), and their effect on the materialcharacteristics was investigated. In the first stage, hydrolysis was favored, while the second stage mostly consisted ofcondensation. Next, the hybrid precursor was copolymerized with a resveratrol-based epoxy resin (RES-ech, Figure1c), and a resveratrol and furfurylamine-based benzoxazine (RES-fa, Figure 1b) in a 1:1 molar ratio, respectively. Thecuring behavior of the systems was investigated by DSC, exhibiting more than one curing process. Additionally, thecopolymers were crosslinked and the materials obtained were characterized by thermogravimetric (TGA), anddynamomechanical analyses (DMTA), obtaining good performance from the mechanical and thermal point of view.