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Open AccessArticle

Cellulose Nanocrystals from Fibers of Macauba (Acrocomia Aculeata) and Gravata (Bromelia Balansae) from Brazilian Pantanal

1
Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentation, P.O. Box 741, 13560-970 São Carlos, SP, Brazil
2
Graduate Program in Materials Science and Engineering (PPGCEM), Federal University of São Carlos (UFSCar), Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP, Brazil
3
Embrapa Pantanal, P.O. Box 109, 79320-900 Corumbá, MS, Brazil
*
Author to whom correspondence should be addressed.
Polymers 2019, 11(11), 1785; https://doi.org/10.3390/polym11111785
Received: 21 September 2019 / Revised: 18 October 2019 / Accepted: 21 October 2019 / Published: 1 November 2019
(This article belongs to the Special Issue Cellulose and Renewable Materials)
Cellulose nanocrystals (CNC) were obtained from macauba and gravata fibers. Macauba (or Bocaiuva) is a palm tree found throughout most of Brazil and Gravata is an abundant kind of bromelia with 1–2m long leaves, found in Brazilian Pantanal and Cerrado. The raw fibers of both fibers were mercerized with NaOH solutions and bleached; they were then submitted to acid hydrolysis using H2SO4 at 45 °C, varying the hydrolysis time from 15 up to 75 min. The fibers were analyzed by X-ray diffraction (XRD), FTIR Spectroscopy, scanning electron microscopy (SEM) and thermal stability by thermogravimetric analysis (TG). XRD patterns did not present changes in the crystal structure of cellulose after mercerization, but it was observed a decrease of hemicellulose and lignin contents, and consequently an increase of cellulose content with the increase of NaOH solution concentration in the mercerization. After acid hydrolysis, the cellulose nanocrystals (CNC) were also analyzed by transmission electron microscopy (TEM) which showed an acicular or rod-like aspect and nanometric dimensions of CNC from both fibers, but the higher values of aspect ratio (L/D) were found on CNC obtained from gravata after 45 min of acid hydrolysis. The mercerization and subsequent bleaching of fibers influenced the crystallinity index and thermal stability of the resulting CNC, but their properties are mainly influenced by the hydrolysis time, i. e., there is an increase in crystallinity and thermal stability up to 45 min of hydrolysis, after this time, both properties decrease, probably due to the cellulose degradation by the sulfuric acid. View Full-Text
Keywords: cellulose nanocrystals; pantanal fibers; gravata; macauba; characterization cellulose nanocrystals; pantanal fibers; gravata; macauba; characterization
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MDPI and ACS Style

Corrêa, A.C.; Carmona, V.B.; Simão, J.A.; Galvani, F.; Marconcini, J.M.; Mattoso, L.H.C. Cellulose Nanocrystals from Fibers of Macauba (Acrocomia Aculeata) and Gravata (Bromelia Balansae) from Brazilian Pantanal. Polymers 2019, 11, 1785.

AMA Style

Corrêa AC, Carmona VB, Simão JA, Galvani F, Marconcini JM, Mattoso LHC. Cellulose Nanocrystals from Fibers of Macauba (Acrocomia Aculeata) and Gravata (Bromelia Balansae) from Brazilian Pantanal. Polymers. 2019; 11(11):1785.

Chicago/Turabian Style

Corrêa, Ana C.; Carmona, Vitor B.; Simão, José A.; Galvani, Fabio; Marconcini, José M.; Mattoso, Luiz H.C. 2019. "Cellulose Nanocrystals from Fibers of Macauba (Acrocomia Aculeata) and Gravata (Bromelia Balansae) from Brazilian Pantanal" Polymers 11, no. 11: 1785.

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