Amazonian Surucucumirá fibers: From native tree to a possible sustainable nano-reinforcement.

Cellulose nanocrystals (CNCs) and nanofibrils (CNFs) were obtained from fibers of a native Amazon tree known as Surucucumirá ( Spathelia excelsa (Krause) Cowan & Brizicky [sin. Sohnroyia excelsa K.]). The chemical composition of the biomass was inspected through TAPPI standards and the lignin and alphacellulose contents were, respectively, around 38.9 % and 31.3 %. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the successful removal of lignin and hemicellulose from the raw fibers without disrupting the cellulose's glycosidic bonds. This is further supported by the scanning electron microscopy (SEM) micrographs, which reveal the fibrillation following the bleaching process. Thermogravimetry (TG) results showed the dependence of intermolecular and intramolecular interactions influencing on thermal stability, with CNFs exhibiting higher stability compared to CNCs. X-ray diffraction (XRD) analysis revealed a significant increase in crystallinity, with the Crystallinity Index (CI) rising from 54.1 % for the raw samples to 89.6 % for the nanocellulose samples. Atomic force microscopy (AFM) nanographs confirmed the successful extraction of both CNCs and CNFs. • Extracted CNCs & CNFs from Surucucumirá. • Characterized nanocellulose using FTIR, SEM, TG, XRD, AFM. • Surucucumirá and similar trees: lower alphacellulose content but rapid growth. • CNCs: high barrier potential due to high specific surface area and low aspect ratio. • CNFs: enhanced mechanical properties potential due to high aspect ratio.