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Journal of Nanomaterials
Volume 2015, Article ID 687490, 11 pages
http://dx.doi.org/10.1155/2015/687490
Research Article

Use of Cellulose and Oxidized Cellulose Nanocrystals from Olive Stones in Chitosan Bionanocomposites

1Cellulose and Paper Department, National Research Centre, 33 Bohouth Street, Dokki, Giza 12622, Egypt
2Faculty of Science, University of Monastir, UR-CAE 13 ES 63, 5000 Monastir, Tunisia
3Université Grenoble Alpes, LGP2, 38000 Grenoble, France
4CNRS, LGP2, 38000 Grenoble, France
5Centre of Excellence for Advanced Sciences, Advanced Materials and Nanotechnology Group, National Research Centre, 33 Bohouth Street, Dokki, Giza 12622, Egypt

Received 20 November 2014; Revised 19 April 2015; Accepted 20 April 2015

Academic Editor: Takuya Tsuzuki

Copyright © 2015 Ragab E. Abou-Zeid et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Cellulose nanocrystals (CNC) and 2,2,6,6-tetramethyl-1-piperidinyloxyl- (TEMPO-) oxidized cellulose nanocrystals (CNC-TEMPO) were prepared from olive stones. The prepared nanocrystals were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and carboxylic groups content determination. The prepared nanocrystals were used as reinforcing elements in chitosan nanocomposites, which were characterized using X-ray diffraction (XRD) and tensile strength properties. In addition, the bioactivity of the prepared chitosan nanocomposites was studied in vitro in simulated body fluid (SBF) using scanning electron microscopy (SEM) and electron diffraction X-ray spectroscopy (EDX). The results showed positive effect of the nanocrystals on tensile strength properties of chitosan and noticeable reduction in its rate of dissolution in SBF due to presence of cellulose nanocrystals. Chitosan nanocomposites containing CNC-TEMPO showed higher tensile strength properties and higher rate of dissolution in SBF than those containing cellulose nanocrystals. Nanocomposites containing CNC or CNC-TEMPO could not form significant amounts of hydroxyapatite (HAp) upon immersion in SBF for up to 4 weeks. Upon addition of nanohydroxyapatite to chitosan/cellulose nanocrystals films, formation of new hydroxyapatite depositions was observed. Presence of cellulose nanocrystals in chitosan/HAp resulted in formation and deposition of higher amounts of new HAp than in case of using chitosan/HAp without cellulose nanocrystals.