•We show an improved X-ray diffraction method for cellulose crystallinity measurement.•We found 2θ range from 10 to 75° is more reliable to quantify cellulose crystallinity index.•The new method may ...be applicable to cellulose of different polymorphs and origins.
We show in this work a modified X-ray diffraction method to determine cellulose crystallinity index (CrI). Nanocrystalline cellulose (NCC) derived from bleached wood pulp was used as a model substrate. Rietveld refinement was applied with consideration of March-Dollase preferred orientation at the (001) plane. In contrast to most previous methods, three distinct amorphous peaks identified from new model samples which used to calculate CrI. A 2 theta range from 10° to 75° was found to be more suitable to determine CrI and crystallite structural parameters such as d-spacing and crystallite size. This method enables a more reliable measurement of CrI of cellulose and may be applicable to other types of cellulose polymorphs.
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•Dendrimers reacting with hairy nanocellulose form dumbbell-shaped structures.•Dendrimers reacted exclusively at the hairy nanocellulose ends.•Dumbbells react further with hairy ...nanocellulose to form network structures.•Linear, star-shaped, and closed-loop structures were formed.•The location of the dendrimers was demonstrated through interactions with latex beads.
Dendrimer-directed assembly of electrosterically stabilized nanocrystalline cellulose (ENCC) to form network structures was studied. ENCC is a member of the family of hairy nanocelluloses and consists of a crystalline rod and dicarboxylated cellulose chains (“hairs”) protruding from both ends, which are very reactive. We hypothesized that covalent linking of ENCC and dendrimers should lead to self-assembled hybrid network structures in which dendrimeric nodes connect cellulose nanorods.
Polyamidoamine (PAMAM) dendrimers were covalently linked to ENCC by a bioconjugation reaction with different ratios of ENCC to PAMAM. To control the self-assembly process and prevent aggregation, acid hydrolysis of ENCC was performed to obtain crew-cut ENCC with shorter hairs and less negative charge. The formation of self-assembled structures from different PAMAM concentrations were analyzed using atomic force microscopy.
It was observed that depending on the concentration of PAMAM, various linear, star-shaped, and closed-loop structures were formed. Also, networks were formed with dendrimers acting as the nodes, connecting long cellulose rods, thus producing a network with a characteristic length of around 100–200 nm, which is difficult to obtain otherwise. We have demonstrated that the reactions of dendrimers with ENCC are solely occurring at the hairs and not at the crystalline regions.
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A cellulose-derived nano-toolbox has been developed via the chemical nano-trimming of electrosterically stabilized nanocrystalline celluloses (ENCCs). ENCC is a member of the class of ...hairy nanocellulose (HNC). The objective of this study is to determine the properties of chemically trimmed HNCs in order to establish whether or not they overcome the surface chemistry and size restrictions of conventional nanocelluloses. The newly “so-called crew-cut ENCCs” emerged by this approach address many technological and environmental challenges in colloidal systems, i.e., drug delivery, anti-scaling and self-assembly. Despite the importance of the crew-cut species, little is known about the systematic changes and the underlying mechanisms of the trimming of their hairs (the chains protruding from both ends of the cylindrical core).
To quantify the effect of the hair trimming on the charge density as well as the kinetics of this process, the carboxylic acid content is determined by conductometric titration as a function of time and reaction conditions. We use electro-acoustic spectroscopy to elucidate the differences in colloidal properties of various crew-cut ENCCs. We focus on the interplay between the time of the acid-catalyzed hydrolysis reaction and tunable parameters, such as size and surface electric charge of ENCC, as well as their microrheological behavior.
We show that a range of hairy ENCCs with various sizes and charge densities is easily obtained by taking advantages of the preferential hydrolysis of the amorphous chains protruding from both ends of the nanocrystals. The trimming mediated by a HCl-catalyzed hydrolysis is initially very fast, but slows down subsequently. The formation of crew-cut species with a smaller particle size and zeta potential was electro-acoustically verified by increasing the reaction time. The longitudinal viscosities of the trimmed ENCC suspensions also decreased with prolonging the reaction time. This research shows how manipulating HNCs enables both scientists and technologists to access a collection of nanocrystals with desired colloidal properties, based on the most abundant biopolymer in the world.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Potential of lignocellulosic biomass towards the preparation of MCC and NCC is explored.•Insight on reaction mechanism for the formation of crystalline derivatives of cellulose is ...provided.•Importance of surface modification of crystalline cellulose is highlighted.•Conventional and emerging applications of MCC and NCC are summarized.•Challenges and perspectives of MCC and NCC are discussed on commercial context.
The present review article is focused on the progress in different aspects of synthesis, modification and advanced applications of both of microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC). First of all, the potential of lignocellulosic biomass towards the formation of MCC and NCC was discussed. Further, different routes for the extraction of the derivatives are individually explained based on the mechanism involved in the formation of MCC and NCC. Moreover, the phenomenon of surface modification was highlighted in order to improve the functionality of the materials. Thereafter, the emerging and advanced applications of both of MCC and NCC are explored in different fields. Finally, the paper is concluded with the challenges that are frequently encountered during the process of commercial production of MCC and NCC. This paper will be beneficial to the readers for acquiring all the important aspects of both of MCC and NCC together in a single article.
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Nanocrystalline cellulose (NCC) have gained great attention owing to their extraordinary properties such as biocompatibility, biodegradability, high crystallinity index (>70%), large surface area ...(~150 m2/g), high aspect ratio (~70), and high tensile strength (7500 MPa). Bast fibers, with compelling features of easy availability, high fiber length, and high cellulose content, are considered to be competitive raw materials to prepare high quality NCC. Generally, NCC can be obtained by mechanical, chemical, biological or combining methods with the removal of non-cellulosic components from bast fibers. This work summarizes the comprehensive research advancement of NCC extracted from bast fibers. Comparison analysis of geometrical dimensions and microstructure morphologies of NCC are conducted to evaluate the strengths and weaknesses of each preparation method. The characterization of NCC and the application of NCC in many emerging fields are systematically introduced. A detailed discussion of current challenges and future outlook are provided to inspire the relevant researchers.
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Removal of heavy metal ions such as copper using an efficient and low-cost method with low ecological footprint is a critical process in wastewater treatment, which can be achieved in a liquid phase ...using nanoadsorbents such as inorganic nanoparticles. Recently, attention has turned toward developing sustainable and environmentally friendly nanoadsorbents to remove heavy metal ions from aqueous media. Electrosterically stabilized nanocrystalline cellulose (ENCC), which can be prepared from wood fibers through periodate/chlorite oxidation, has been shown to have a high charge content and colloidal stability. Here, we show that ENCC scavenges copper ions by different mechanisms depending on the ion concentration. When the Cu(II) concentration is low (C 0 ≲ 200 ppm), agglomerates of starlike ENCC particles appear, which are broken into individual starlike entities by shear and Brownian motion, as evidenced by photometric dispersion analysis, dynamic light scattering, and transmission electron microscopy. On the other hand, at higher copper concentrations, the aggregate morphology changes from starlike to raftlike, which is probably due to the collapse of protruding dicarboxylic cellulose (DCC) chains and ENCC charge neutralization by copper adsorption. Such raftlike structures result from head-to-head and lateral aggregation of neutralized ENCCs as confirmed by transmission electron microscopy. As opposed to starlike aggregates, the raftlike structures grow gradually and are prone to sedimentation at copper concentrations C 0 ≳ 500 ppm, which eliminates a costly separation step in wastewater treatment processes. Moreover, a copper removal capacity of ∼185 mg g–1 was achieved thanks to the highly charged DCC polyanions protruding from ENCC. These properties along with the biorenewability make ENCC a promising candidate for wastewater treatment, in which fast, facile, and low-cost removal of heavy metal ions is desired most.
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The extraction of nanocrystalline cellulose from agro-residues is an interesting alternative to recover these materials. In the present study, nanocrystalline cellulose was extracted from pine wood ...and corncob. In addition, microcrystalline cellulose was used as a reference to compare results. Initially, the lignocellulosic residues were submitted to delignification pre-treatments. At the end of the process, the bleached fibre was submitted to acid hydrolysis. Additionally, microparticles were obtained from the spray-drying of the nanocrystalline cellulose suspensions. The nanocrystalline cellulose yield for the pine wood was 9.0-% of the value attained for the microcrystalline cellulose. For the corncob, the value was 23.5-%. Therefore, complementary studies are necessary to improve the yield. The spray-dried microparticles showed a crystallinity index of 67.8-% for the pine wood, 70.9-% for the corncob and 79.3-% for the microcrystalline cellulose. These microparticles have great potential for use in the production of polymer composites processed by extrusion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In order to meet the growing energy crisis of the 21st century, the utilization of bio-based materials has become a field of high research endeavour. In view of that, the present review paper is ...focused on different techniques that are frequently explored for the synthesis of value-added crystalline derivatives of cellulose like MCC and NCC from agricultural wastes and forest residues. Moreover, a comparative analysis between thermochemical and biochemical methods is carried out for such valorization of biomass considering the mechanism involved with various reactions. Further, a critical analysis is performed on various individual techniques specifically used for the applications of MCC and NCC in different fields including environmental, polymer industry, pharmaceutical and other emerging sectors. This article will assist the readers not only to explore new biomass sources but also provides an in-depth insight on various green and cost-effective methods for sustainable production of crystalline cellulose.
•Potential of agricultural wastes and forest residues towards the production of crystalline cellulose was explored.•The conventional methods of synthesis of MCC and NCC and the involved mechanisms were summarized.•Comparison of the conventional thermochemical and biochemical methods was discussed.•The various methods used for the environmental, industrial and other potential applications of MCC and NCC are summarized.•Commercial aspects of MCC and NCC production from agricultural wastes and forest residues were discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Novel material for SO2 capture at low concentration streams at low temperature.•SO2 capacity for amine-functionalized nanocrystalline cellulose six times higher.•Green amine functionalization method ...for nanocrystalline cellulose for SO2 affinity.
Adsorbents made from cellulose derivatives have been widely studied for removal of contaminants such as toxic gases, pharmaceutical ingredients, dyes, and metals due to the availability, cost-effectiveness, and non-contaminating nature of these adsorbents. In this study, amine-functionalized cellulose is proposed as a green adsorbent for SO2 capture. Cellulose nanocrystals were chemically modified with ethylenediamine (EDA) using a solvent-free method. The surface modification was confirmed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), solid-state carbon nuclear magnetic resonance (13C NMR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and elemental analysis. The effects of functionalization time, temperature, and amount of EDA on the SO2 capture capacity were assessed. During these investigations, the highest adsorption capacity obtained was 2.07 mg-SO2/gsorbent, which is six times higher than for pristine nanocrystalline cellulose (NCC) used under the same conditions. Furthermore, the effect of various operating adsorption temperatures and flow rates was investigated. When the temperature was reduced, there was a significant increase in capture capacity and breakthrough time, confirming an adsorption mechanism for SO2 capture. It was also confirmed that as the flow rate of the feed gas increases, the breakthrough time decreases, as expected, with a steeper breakthrough curve, because of the faster transport of the adsorbate molecules.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•SPNCCs were successfully isolated from sugar palm fibres via hydrolysis process.•The SPS/SPNCCs showed improvement in mechanical, thermal and physical properties.•The 0.5 wt% SPNFCs ...loaded SPS films showed 140% improved tensile strength.•WA, WS and WVTR results showed improved water barrier property of SPS/SPNFCs film.
Sugar palm fibre (SPF) was treated with NaClO2, bleached with NaOH and subsequently hydrolyzed with acid to obtain sugar palm nanocrystalline cellulose (SPNCCs). Bionanocomposites in the form of films were prepared by mixing sugar palm starch (SPS) and sorbitol/glycerol with different nanofiller SPNCCs compositions (0–1.0 wt%) using solution casting method. The resulting fibres and nanocomposites were characterized in terms of morphology (FESEM and TEM), footprint, crystallinity (XRD), light transmittance, biodegradability, physical, water barrier, thermal (TGA, DSC and DMA) and mechanical properties. The length (L), diameter (D) and L/D values of the SPNCCs were 130 ± 30.23, 8.5 ± 1.82 nm, and 15.3, respectively. The SPS/SPNCCs nanocomposite films exhibited higher crystallinity, tensile strength, Young’s modulus, thermal and water-resistance compared to the neat SPS film. The results showed that the tensile strength and moduli of the bionanocomposites increased after being reinforced with SPNCCs and the optimum nanofiller content was 0.5%.
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