AVALIAÇÃO DE COMPÓSITOS SANDUÍCHE UTILIZANDO FIBRAS DE SISAL COM TRATAMENTO ALCALINO E RESINA EPÓXI NAS FACES COM NÚCLEO HONEYCOMB DE PETG E PLA OBTIDOS POR IMPRESSORA 3D

Sandwich panels are widely used in the Naval and Aerospace industries. The panel core, in turn, must keep the faces apart and be rigid perpendicular to them. In this work, a study was carried out using a 3-point flexural test of sandwich panels using composite material faces with Sisal fibers subjected to alkaline treatment with 10% by weight of sodium hydroxide and an immersion time of 4 hours in dissolution in epoxy resin matrix. The honeycomb structure core of PETG and PLA were obtained by 3D printer. As a result of the work, it was observed that Sisal fibers with chemical treatment in an epoxy resin matrix can be used on the faces of Sandwich composites in the same way as cores made by 3D printers when compared with previously published works. The results demonstrated that sandwich composites perform better with PETG, a type of polymer that is more resistant than PLA, used in 3D printing. In all tests, PETG was 21% to 32% more resistant than PLA. Although there was no rupture in the specimens, the PETG cores deformed 0.5% to 3.6% less than PLA. The PLA composites were lighter, due to the core density being 13.8% lower than the PETG cores. Increasing the height of the honeycomb increased the resistance.