Preparation Of Nanocrystalline Cellulose Research Articles

Effects of HCl Hydrolyzed Cellulose Nanocrystals From Waste Papers on the Hydroxypropyl Methylcellulose/Cationic Starch Biofilms

PurposeThe study reports on the preparation of nanocrystalline cellulose from waste papers (WPNCC), as an environmental friendly approach of source material and investigation of their effects on the morphological, mechanical and barrier properties of the Hydroxypropyl methylcellulose/Cationic starch (HPMC/CS) nanocomposites.MethodsThe HCl hydrolysis followed by alkali treatment and deinking of the fibers resulted in the production of WPNCC. Also, the HPMC/CS nanocomposites were produced by solvent casting method.ResultsThe TEM results confirmed the rod like shape of WPNCC; the average diameter was 22 ± 7 nm and the length was 125 ± 25 nm. The hydrolysis yield was 65% with high crystallinity index of 79.6%. The results of X-ray diffraction confirmed the successfully production of WPNCC and their effective presence in the HPMC/CS matrix. The homogeneity of WPNCC dispersion in the polymer matrix was approved by FESEM analysis. The WPNCC also did not affect the nanocomposites optical clarity.ConclusionThe optimum amount of 9 wt% WPNCC, showed the highest barrier, mechanical and biodegradablility properties. It can prove that these nanocomposites can be considered as a new biomaterial for application in food packaging and conservation.Graphical Abstract

Nanocrystalline cellulose from waste paper: Adsorbent for azo dyes removal

The preparation of nanocrystalline cellulose from waste printed papers as adsorbent was conducted using organic solvent. The synthesize of nanocrystalline cellulose is characterized by Fourier transform-infra red (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Hydroxynaphtol blue and congo red in aqueous solutions are used as sorbate in this study to test the single system adsorption capacity of nanocrystalline cellulose using Langmuir and Freundlich isotherm models at 30, 40, and 50 °C. Kinetic study are quantified using pseudo-first order and pesudo-second order models. The adsorption of both azo dyes resulted in negative value of ΔG° which shows spontaneous adsorption of both azo dyes onto adsorbent active sites. Higher temperature increase the adsorption of dyes represents the endothermic nature of adsorption and randomness of adsorbent-solution interface.

Isolation and Characterization of Microcrystalline Cellulose and Preparation of Nano-Crystalline Cellulose from Tropical Water Hyacinth

Because of the conservation problems causes by the existence of water hyacinth (W.H) as an watery plant in water bodies of Iraq, our study aimed to make use of (W.H) by isolation of microcrystalline cellulose, and a new method of preparation of Nano crystalline cellulose. Microcrystalline cellulose was produced using base bleaching method by sodium hypochlorite [NaOCl] to remove unorganized region of cellulose and lignin to create particles comprising of micro crystal and preparing of Nano crystalline cellulose from microcrystalline cellulose by acid hydrolysis and ultrasonic treatment. The Nano crystalline and microcrystalline cellulose characterized by AFM, FTIR, XRD and TGA. FT-IR spectra of microcrystalline cellules and Nano crystalline cellulose show peaks at (1076.28, 1058.92) cm-1 and (1118.71, 1112.93) cm-1 refer to the stretching vibration of C–O and stretching vibration intermolecular ester bonding. 
 The AFM image shows that isolated microcrystalline cellulose have a diameter of (141.37 nm) and the prepared Nano crystalline have a diameter of (87.39 nm). The Thermo gravimetric analysis of cellulose showed a high decomposition temperature at (283°C) for microcrystalline cellulose and (253)°C for Nano crystalline cellulose .The thermal stability of microcrystalline cellulose was more than Nano crystalline cellulose XRD result possessed a segal crystallinity index of 92.8 % and a average crystal size of 41.7 A ° for Nano crystalline cellulose and a Segal Crystallinity Index of 86.4 % and a average crystal size of 55.3°A of microcrystalline cellulose.

Nanocrystalline Cellulose from Flax Stalks: Preparation, Structure, and Use

Preparation of nanocrystalline cellulose by acid hydrolysis of flax cellulose is described. According to atomic-force microscopy, the obtained nanocrystals were needle-like with average diameter 85 ± 39 nm and length 158 ± 89 nm. The potential of using nanocrystalline flax cellulose as an adhesive for heat-protective porous ceramics and an anisotropic reinforcing filler of polymer films was investigated.

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 −21.8mV, 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 93.89m2/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.

Preparation of Nanocrystalline Cellulose from Corncob Acid-Hydrolysis Residue and Its Reinforcement Capabilities on Polyvinyl Alcohol Membranes

The sodium chlorite process was utilized successfully to remove the lignin from corncob acid-hydrolysis residue (CAHR), and the intermediate was used to prepare nanocrystalline cellulose (NCC) with a very mild ultrasonic treatment (600W). When the duration of the ultrasonic treatment increased, the absolute value of the zeta potential became stronger and the particle size smaller. When the duration reached 30 minutes, the zeta potential of the NCC reached −23mV, and the particle size was 28.7 nm. The FTIR, XRD, and TEM analysis results proved that the cellulose product was nanocrystalline in Type I structure with a high crystallinity index (79.74%), with a diameter less than 10 nm. The reinforcement of polyvinyl alcohol (PVA) membranes using NCC was also investigated. When the dosage of the NCC was 1.0 wt.%, the tensile strength increased from 34 MPa to 37 MPa. This work provides a novel and cost-effective way to utilize corncob acid-hydrolysis residue.

Preparation of nanocrystalline cellulose via ultrasound and its reinforcement capability for poly(vinyl alcohol) composites

Rod-shaped nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) using the purely physical method of high-intensity ultrasonication. Scanning electron microscopy, transmission electron microscopy, and X-ray diffraction was used for the characterization of the morphology and crystal structure of the material. The thermal properties were investigated using thermogravimetric analysis. The reinforcement capabilities of the obtained NCC were investigated by adding it to poly(vinyl alcohol) (PVA) via the solution casting method. The results revealed that the prepared NCC had a rod-shaped structure, with diameters between 10 and 20 nm and lengths between 50 and 250 nm. X-ray diffraction results indicated that the NCC had the cellulose I crystal structure similar to that of MCC. The crystallinity of the NCC decreased with increasing ultrasonication time. The ultrasonic effect was non-selective, which means it can remove amorphous cellulose and crystalline cellulose. Because of the nanoscale size and large number of free-end chains, the NCC degraded at a slightly lower temperature, which resulted in increased char residue (9.6–16.1%), compared with that of the MCC (6.2%). The storage modulus of the nanocomposite films were significantly improved compared with that of pure PVA films. The modulus of PVA with 8 wt.% NCC was 2.40× larger than that of pure PVA.

Nanocelluloses: A New Family of Nature‐Based Materials

Cellulose fibrils with widths in the nanometer range are nature-based materials with unique and potentially useful features. Most importantly, these novel nanocelluloses open up the strongly expanding fields of sustainable materials and nanocomposites, as well as medical and life-science devices, to the natural polymer cellulose. The nanodimensions of the structural elements result in a high surface area and hence the powerful interaction of these celluloses with surrounding species, such as water, organic and polymeric compounds, nanoparticles, and living cells. This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants.