Preparation and evaluation of nanocrystalline cellulose aerogels from raw cotton and cotton stalk

Suspensions of nanocrystalline cellulose (NCC) were prepared by sulfuric acid hydrolysis of cotton and cotton stalk bleached pulps. The original pulps extracted from cotton and cotton stalk were analyzed by FT-IR spectroscopy, X-ray diffraction and scanning electron microscopy. The NCC products were investigated and their differences in morphology and other characteristics such as crystallinity index (CrI), zeta potential, particle size and thermal stability were studied. The results suggested that the pulp yields from cotton and cotton stalk were 77 and 23%, respectively. Raw cotton resulted in pulps with much higher quality than cotton stalk. Zeta potentials of the nanocrystalline cellulose obtained from cotton, (C-NCC), and cotton stalk, (CS-NCC), were -27.5 and -21.8 mV, respectively, in the stable range. TEM micrographs of both nanocrystalline cellulose presented rod like shapes of different dimensions. Surface areas of the aerogels prepared from cotton nanocrystalline cellulose, C-NCE, and cotton stalk nanocrystalline cellulose, CS-NCE, were 91.47 and 93.89 m(2)/g, respectively. This study shows that the differences in characteristics of nanocrystalline cellulose and aerogel products obtained from cotton and cotton stalk pulps are not significant. Thus, the use of cotton stalk instead of cotton in the preparation of nanocrystalline cellulose and aerogel will be cost effective and environmentally friendly. (C) 2016 Published by Elsevier B.V.