Facile Approach for the Dispersion of Regenerated Cellulose in Aqueous System in the Form of Nanoparticles

Dissolution of cellulose in imidazolium-based double salt ionic liquids

The dissolution of cellulose in double salt ionic liquids (DSILs) was studied in detail and compared with the dissolution in individual constituent ionic liquids (ILs). The DSILs, [C4mim](CH3CO2)xCl1-x (x is the mole fraction of the single component ILs), were synthesized using acetate and chloride salts of 1-butyl-3-methylimidazolium. These DSILs were then used for the investigation of the solubility of cellulose in the whole mole fraction range. Commercial cellulose (CC) powder, kraft pulp (KP), and prehydrolysis kraft pulp (PHKP) of jute were chosen as cellulose sources. The solubility of cellulose increased with an increasing temperature for [C4mim](CH3CO2)0.6Cl0.4 and with increasing amount of [C4mim]Cl in DSILs. The maximum solubility of CC powder was 32.8 wt% in [C4mim](CH3CO2)0.6Cl0.4 at 100 °C, while for KP and PHKP, solubilities were 30.1 and 30.5 wt%, respectively under the identical condition. Cellulose could be regenerated from the DSILs using water as an antisolvent. Structure, morphology, and thermal stability of the regenerated cellulosic materials were analyzed. DSILs could be recycled >99 % without a discernible change in structure. This work demonstrates that DSILs display enhanced solubility over ILs system and have potential as a chemical processing methodology.

New fluorescent Schiff base modified nanocellulose-based chemosensors for the selective detection of Fe3+, Zn2+ and Cu2+ in semi-aqueous media and application in seawater sample

Stimulus-responsive fluorescent-modified biopolymers have received significant attention in the field of chemosensors. Herein, four new fluorescent dyes, namely, S1: (PDA-DANC), S2: (SAL-PDA-DANC), S3: (BrSAL-PDA-DANC) and S4: (ClSAL-PDA-DANC) have been successfully synthesized from 2,3-dialdehyde nanocellulose (DANC) for the detection of heavy metals. The microstructural and photophysical properties of nanocellulose (NC), microcrystalline cellulose (DANC) and the synthesized S1 to S4 dyes were investigated by FT-IR, SEM-EDX, XRD, TGA, DLS and photoluminescence. NC, obtained from conversion of MCC, shows an average size of 802.4 nm with 0.141 of polydispersity index (PdI), and a crystalline index (CI) of 82.40 % and crystallite size of 4.68 nm. The synthesized dyes present good fluorescent properties and have been therefore exploited for developing new probes for heavy metal ions detection. Remarkable "turn off" and/or "turn on" behaviors with Fe3+ and Cu2+ and with Zn2+ in DMF/water solution have been demonstrated, allowing the sensitive and selective determination of these heavy metal ions with a low limit of detection (LOD). Finally, the evaluation of the Fe3+ sensing in a real seawater sample was investigated.

Nanocellulose-stabilized bitumen emulsions as a base for preparation of nanocomposite asphalt binders

Pickering bitumen emulsions stabilized by 1 % aqueous dispersion of microfibrillated cellulose (MFC) were used to obtain micro- and nanocomposite asphalt binders. Initial bitumen emulsions are characterized by a yield stress for a bitumen content of up to 40 %, while higher bitumen amounts result in phase inversion with the formation of highly viscous inverse emulsions. Drying of emulsions leads to the production of nanocomposite bitumen binders containing from 0.6 % to 8.3 % of MFC. In this case, the MFC content of 1.5 % or more formed a microfibrillar network in the bitumen, which gives it gel-like properties and the yield stress, increasing its cohesive strength and resistance to rutting. The effect of addition of 5 % sodium dodecyl sulfate (SDS) on the properties of the bitumen emulsions and the resulting binders is considered. SDS increases the emulsifying ability of MFC, making it possible to obtain 70 % direct bitumen emulsions and reducing their effective viscosity together with the yield stress. However, the presence of SDS in the dried binders increases the aggregation of MFC, reducing the stiffness of the resulting microcomposite binders, their yield stress, and rutting resistance.

In Situ Synthesis of Environmentally Friendly Waterborne Polyurethane Extended with Regenerated Cellulose Nanoparticles for Enhanced Mechanical Performances

The development of waterborne polyurethane (WPU) has been stimulated as an alternative to solvent-based polyurethanes due to low-VOC alternatives and reduced exposure to solvents. However, their relatively low mechanical performance and degradation have presented challenges in their wide application. Here, we developed environmentally-friendly bio polyol-based WPU nanocomposite dispersions and films, and presented the optimal process conditions for their manufacture. Additionally, the condition was established without using harmful catalysts or ethyl methyl ketone (MEK) during the polymerization. Moreover, regenerated cellulose nanoparticles (RCNs) were employed as natural chain-extenders in order to improve the biodegradability and mechanical performances of the nanocomposite films. The RCNs have a lower crystallinity compared to cellulose nanocrystals (CNCs), allowing them to possess high toughness without interfering with the elastomeric properties of polyurethane. The prepared CWPU/RCNs nanocomposite films exhibited high toughness of 58.8 ± 3 kgf∙mm and elongation at break of 240 ± 20%. In addition, depending on the molar ratio of NCO/OH, the polyurethane particle size is variously controlled from 70 to 230 nm, enabling to fabricate their dispersions with various transmittances. We believe that our findings not only open a meaningful path toward green elastomers with biodegradability but provides the design concept for bio-elastomers in order to develop industrial elastomers with mechanical and thermal properties.

All-cellulose air filter composed with regenerated nanocellulose prepared through a facile method with shear-induced

High-speed shear system is usually used for the dispersion improvement of slurry, nanomaterials preparation, and even two-dimensional materials production. However, there is barely study that focused on the regenerated cellulose (RC) which was coagulated with shear induced. In this work, a new type of all-cellulose air filter was fabricated through high-speed shear in aqueous regeneration system using parenchyma cellulose from corn stalk. The obtained RC were aggregated by ribbon-like fine cellulose and nanocellulose sheets. The study exhibited the micro-structure of RC displayed excellent unidirectional alignment and a relatively high crystallinity. All-cellulose air filter which was produced via RC presented excellent filtration efficiency (PM_2.5 97.3 %, PM_10.0 97.7 %) with slightly pressure drop (19 Pa). Therefore, this work provides a facile method to obtain a novel RC with nanocellulose particles used for air filtration, which gives an effective strategy application in the conversion of all-cellulose materials from agricultural waste.

Chemical and Enzymatic Fiber Modification to Enhance the Mechanical Properties of CMC Composite Films

Carboxymethyl cellulose (CMC) is a cellulose derivative that can be obtained from wood, bamboo, rattan, straw, and other cellulosic materials. CMC can be used to produce biofilms for many purposes, but the properties of these resulting films make them unsuitable for some applications. The effects of three kinds of plant fiber addition on CMC film properties was investigated using CMC derived from eucalyptus bark cellulose. Tensile strength (TS) and elongation at break (EB) of CMC/sodium alginate/glycerol composite films were 26.2 MPa and 7.35%, respectively. Tensile strength of CMC composite films substantially increased, reaching an optimum at 0.50 g of fiber. The enhancement due to industrial hemp hurd fiber on CMC composite films was more obvious. Pretreatment with hydrogen peroxide (H₂O₂) and glacial acetic acid (CH₃COOH) produced films with a TS of 35.9 MPa and an EB of 1.61%. TS values with pectinase pretreated fiber films was 41.3 MPa and EB was 1.76%. TS of films pretreated with pectinase and hemicellulase was 45.2 MPa and EB was 4.18%. Chemical and enzymatic treatment both improved fiber crystallinity, but film tensile strength was improved to a greater extent by enzymatic treatment. Surface roughness and pyrolysis residue of the film increased after fiber addition, but Fourier transform infrared spectroscopy (FTIR), opacity, and water vapor transmission coefficients were largely unchanged. Adding fiber improved tensile strength of CMC/sodium alginate/glycerol composite films and broadened the application range of CMC composite films without adversely affecting film performance.

Synthesis of cellulose II-based spherical nanoparticle microcluster adsorbent for removal of toxic hexavalent chromium

Since natural cellulose is mostly cellulose I and has a fibrous form, most cellulose-based adsorbents are fibrous/rod-shaped and exhibit the cellulose I crystal structure. This study reports a cellulose II-based spherical nanoparticle microcluster adsorbent (SNMA), synthesized from biomass by a bottom-up approach, for removing toxic hexavalent chromium (Cr(VI)). The basic structure of SNMA was investigated. Notably, the prepared adsorbent was a microcluster composed of spherical nanoparticles, while exhibiting cellulose II crystal structure, resulting in higher thermal stability and significantly enhanced adsorption performance. The adsorption process and mechanism of SNMA on Cr(VI) were studied in detail. The SNMA achieved a high adsorption capacity (225.94 mg/g) and receptor site density. The SNMA is expected to be used as a bio-based spherical nanoparticle microcluster adsorbent platform for the adsorption of different toxic substances by changing the surface functional groups of its components, spherical nanoparticles.

Morphologically favorable mutant of Trichoderma reesei for low viscosity cellulase production

Metabolite production by filamentous fungi hampered because of high viscosity generated during growth. Low viscosity fermentation by mold is one of the preferred ways of large scale enzymes production. Cellulolytic enzymes play a key role during the process of lignocellulosic biomass conversion. In this study a mutant RC-23-1 was isolated through mutagenesis (diethyl sulfate followed by UV) of T. reesei RUT-C30. RC-23-1 not only gave higher cellulase production but also generated lower viscosity during enzyme production. Viscosity of mutant growth was more than three times lower than parent strain. RC-23-1 shows unique, yeast like colony morphology on solid media and small pellet like growth in liquid media. This mutant did not spread like mold on solid media. This mutant produces cellulases constitutively when grown in sugars. Using only glucose, the cellulase production was 4.1 FPU/ml. Among polysaccharides (avicel, xylan and pectin), avicel gave maximum of 6.2 FPU/ml and pretreated biomass (rice straw, wheat straw and sugarcane bagasse) produced 5.1-5.8 FPU/ml. At 7L scale reactor, fed-batch process was designed for cellulase production using different carbon and nitrogen sources. Maximum yield of cellulases was 182 FPU/g of lactose consumed was observed in fed-batch process. The produced enzyme used for hydrolysis of acid pretreated rice straw (20% solid loading) and maximum of 60 % glucan conversion was observed. RC-23-1 mutant is good candidate for large scale cellulase production and could be a model strain to study mold to yeast-like transformation. This article is protected by copyright. All rights reserved.

Feasibility of bionanocomposite films fabricated using capsicum leaf protein and cellulose nanofibers

In this study, the feasibility of fabricating protein-based bionanocomposite films (PBBFs) was analysed by applying capsicum leaf protein (CLP) and cellulose nanofiber (CNF) as raw materials. The effects of different amounts of CNF (solid content 2%) on physicochemical and material properties of PBBFs were investigated. The results showed nanoscale CNFs exhibited good interfacial compatibility with CLP. The hydroxyl groups on the CNF surface promoted the association of hydrogen bonds between CLP, glycerol and CNF, which improved the crystal structure and thermal stability of PBBFs. Concurrently, the mechanical properties and hydrophobicity of PBBFs are also enhanced. PBBFs with 60% CNF content have maximum flexibility and hydrophobicity. All PBBFs exhibited ultraviolet barrier performance, indicating that PBBFs had potential application prospects in the development of degradable food packaging materials. The results of the present study can provide a theoretical basis for the efficient utilisation of capsicum planting waste while improving the ecosystem.

Cellulose nanosphere: Preparation and applications of the novel nanocellulose

Over the past few years, cellulose nanosphere (CNS) has gained growing attention and rapid development. As a new type of nanocellulose materials, CNS can be prepared from native cellulose by using methods which have been adopted extensively to prepare the well-known nanocelluloses, i.e., cellulose nanofiber and cellulose nanocrystal. The particular interest is that the regenerated cellulose and mercerized cellulose can also be used as important feedstocks to produce CNS. In this review, the preparation methods of CNS are described and discussed, via both top-down processes, including chemical, mechanical, and enzymolysis ones, and bottom-up processes by using various cellulose I and II starting materials. This review also highlights the researches relative to cellulose composite nanospheres, and summarizes the applications of spherical cellulose-based nanoparticles. Finally, the future challenges and opportunities of CNS are prospected in this work.

Tailor-made urethane-linked alkyl-celluloses: A Promising Stabilizer for Oil-in-oil Pickering Emulsions

Oil-in-oil emulsions or nonaqueous emulsions are formulated from two immiscible organic solvents, which provide an ideal platform for water-sensitive systems such as readily hydrolyzable reagents and polymerization in anhydrous conditions....

Regenerated Cellulose Products for Agricultural and Their Potential: A Review

Cellulose is one of the most abundant natural polymers with excellent biocompatibility, non-toxicity, flexibility, and renewable source. Regenerated cellulose (RC) products result from the dissolution-regeneration process risen from solvent and anti-solvent reagents, respectively. The regeneration process changes the cellulose chain conformation from cellulose I to cellulose II, leads the structure to have more amorphous regions with improved crystallinity, and inclines towards extensive modification on the RC products such as hydrogel, aerogel, cryogel, xerogel, fibers, membrane, and thin film. Recently, RC products are accentuated to be used in the agriculture field to develop future sustainable agriculture as alternatives to conventional agriculture systems. However, different solvent types and production techniques have great influences on the end properties of RC products. Besides, the fabrication of RC products from solely RC lacks excellent mechanical characteristics. Thus, the flexibility of RC has allowed it to be homogenously blended with other materials to enhance the final products' properties. This review will summarize the properties and preparation of potential RC-based products that reflect its application to replace soil the plantation medium, govern the release of the fertilizer, provide protection on crops and act as biosensors.

Excellent coating of collagen fiber/chitosan-based materials that is water- and oil-resistant and fluorine-free

Collagen fiber has attracted much attention due to its good biocompatibility and biodegradability. In the present research, we prepared a type of non-fluorine hydrophobic and oil-resistant material using collagen fiber, chitosan, and polydimethylsiloxane (PDMS) as raw materials. To improve oil/grease resistance, the first layer filled the porous matrix and was made from the cross-linking product of collagen fiber/chitosan and glutaraldehyde. This was followed by a simple coating of PDMS, to increase hydrophobicity and water resistance. Notably, 10 g/m² of cross-linking product and 6 g/m² of PDMS had a low pore size as well as a smooth and uniform surface, which made the composites exhibit excellent hydrophobic and oil-resistant properties (water contact angles of 141°), water and oil resistance (kit rating value of 12/12) and mechanical properties. Fluorine-free environment-friendly materials with high water and oil resistance play an important role in promoting the development of high-performance materials for food packaging.

A Fast Dissolution Pretreatment to Produce Strong Regenerated Cellulose Nanofibers via Mechanical Disintegration

This study investigates a fast dissolution and regeneration pretreatment to produce regenerated cellulose nanofibers (RCNFs) via mechanical disintegration. Two cellulose pulps, namely, birch and dissolving pulps, with degree of polymerizations of 1800 and 3600, respectively, were rapidly dissolved in dimethyl sulfoxide (DMSO) by using tetraethylammonium hydroxide (TEAOH) as aqueous electrolyte at room temperature. When TEAOH (35 wt % in water) was added to the pulp-DMSO dispersion (pulp:DMSO and TEAOH:DMSO weight ratios of 1:90 and 1:9, respectively), 95% of the dissolving pulp and 85% of the birch pulp fibers dissolved almost immediately. Addition of water caused the regeneration of cellulose without any chemical modification and only a minor decrease of DP, whereas the crystallinity structure of cellulose transformed from cellulose I to cellulose II. The regenerated cellulose could then be mechanically disintegrated into nanosized fibers with only a few passes through a microfluidizer, and RCNF showed fibrous structure. The specific tensile strength of the film produced from both RCNFs exceeded 100 kN·m/kg, and overall mechanical properties of RCNF produced from birch pulp were in line with reference CNF produced by using extensive mechanical disintegration. Although the thermal stability of RCNFs was slightly lower compared to their corresponding original cellulose pulp, the onset temperature of degradation of RCNFs was over 270 °C.

A novel nanocomposite based on covalent organic polymer and nanocellulose for thin-film microextraction of imipramine from biological samples

A novel covalent organic polymer was prepared using 1,5-diaminonaphthalene as a linker and cyanuric chloride as a node. A thin-film nanocomposite of 1,5-diaminonaphthalene covalent organic polymer and cellulose nanocrystalline was then fabricated via filtering and casting method. The effect of incorporation of various amounts of 1,5-diaminonaphthalene covalent organic polymer and cellulose nanocrystalline was studied to obtain an efficient nanocomposite thin-film with a large number of polar functional groups and high mechanical stability. Field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, and thermogravimetric analysis techniques were applied for the characterization of physicochemical properties of the prepared materials. Imipramine was determined in the biological samples using thin-film microextraction followed by gas chromatography flame ionization detection. Parameters affecting the extraction efficiency of imipramine were investigated. Under the optimized conditions, the limit of detection was 0.5 ng/mL. Film-to-film reproducibility for three different films fabricated under the same conditions (at three concentration levels) varied between 8.9 and 9.7%. The linear dynamic range covered more than three orders of magnitude (2-5000 ng/mL) with a determination coefficient of 0.9985. The method was successfully applied for preconcentration and determination of imipramine in biological samples with spiking recoveries between 78 and 93%.

Preparation and characterization of curdlan/nanocellulose blended film and its application to chilled meat preservation

In this study, to improve the mechanical and thermal properties of curdlan film, a curdlan/nanocellulose (NC) blended film was prepared and characterized for the first time. NC was successfully prepared from microcrystalline cellulose (MCC) with NaOH/urea treatment. The particle size of NC was observed to be 70-140 nm by cryo-electron microscope (cryo-EM). The blended film was prepared by adding the NC to curdlan solution. The tensile strength (TS) of the blended film reached the maximum value of 38.6 MPa, and the elongation at break (EB) was 40%. The DSC curve showed that the heat absorption peak of the film was 240 °C, indicating that the blended film has good temperature stability. Additionally, some other film properties were also improved, including gas barrier properties and transparency. Obvious morphological and molecular differences between the blended film and the pure curdlan film were discovered by SEM and FTIR analysis. Finally, the blended film was used for the preservation of chilled meat and extended the storage time of meat to 12 days. These results provided a theoretical basis for future application and development of biodegradable film.

Preparation of Cellulose Nanofibers from Bagasse by Phosphoric Acid and Hydrogen Peroxide Enables Fibrillation via a Swelling, Hydrolysis, and Oxidation Cooperative Mechanism

Due to the natural cellulose encapsulated in both lignin and hemicellulose matrices, as well as in plant cell walls with a compact and complex hierarchy, extracting cellulose nanofibers (CNFs) from lignocellulosic biomass is challenging. In this study, a sustainable high yield strategy with respect to other CNF preparations was developed. The cellulose was liberated from plant cell walls and fibrillated to a 7-22 nm thickness in one bath treatment with H₃PO₄ and H₂O₂ under mild conditions. The cellulose underwent swelling, the lignin underwent oxidative degradation, and the hemicellulose and a small amount of cellulose underwent acid hydrolysis. The CNFs' width was about 12 nm, with high yields (93% and 50% based on cellulose and biomass, respectively), and a 64% crystallinity and good thermal stability were obtained from bagasse. The current work suggests a strategy with simplicity, mild conditions, and cost-effectiveness, which means that this method can contribute to sustainable development for the preparation of CNFs.

A New Approach Based on Glued Multi-Ultra High Molecular Weight Polyethylene Forms to Fabricate Bone Replacement Products

Three types of glue based on thiol-ene reaction, polyvinyl alcohol (PVA)/cellulose, and phenol formaldehyde were prepared and applied on modified ultra-high molecular weight polyethylene (UHMWPE) samples grafted by cellulose. In comparison with unmodified UHMWPE samples, T-peel tests on the modified and grafted UHMWPE films showed an increase in the peel strength values for the glues based on thiol-ene reaction, PVA/cellulose, and phenol formaldehyde by 40, 29, and 41 times, respectively. The maximum peel strength value of 0.62 Kg/cm was obtained for the glue based on phenol formaldehyde. Mechanical tests for the cylindrical multi-UHMWPE forms samples, made of porous UHMWPE as a trabecular layer and an armored layer (cortical layer) that consists of bulk and UHMWPE films, indicated an improvement in the mechanical properties of these samples for all glue types, as a result of the UHMWPE films existence and the increase in the number of their layers. The maximum compressive yield strength and compressive modulus values for the armored layer (bulk and six layers of the UHMWPE films using the glue based on thiol-ene reaction) were 44.1 MPa (an increase of 17%) and 1130 MPa (an increase of 36%), respectively, in comparison with one armored layer of bulk UHMWPE. A hemocompatibility test carried out on these glues clarified that the modified UHMWPE grafted by cellulose with glues based on PVA/cellulose and thiol-ene reaction were classified as biocompatible materials. These multi-UHMWPE forms composites can be considered a promising development for joint reconstruction.

Effects of Preparation Method on the Physicochemical Properties of Cationic Nanocellulose and Starch Nanocomposites

Nanocellulose (NC) has attracted attention in recent years for the advantages offered by its unique characteristics. In this study, the effects of the preparation method on the properties of starch films were investigated by preparing NC from cationic-modified microcrystalline cellulose (MD-MCC) using three methods: Acid hydrolysis (AH), high-pressure homogenization (HH), and high-intensity ultrasonication (US). When MD-MCC was used as the starting material, the yield of NC dramatically increased compared to the NC yield obtained from unmodified MCC and the increased zeta potential improved its suspension stability in water. The NC prepared by the different methods had a range of particle sizes and exhibited needle-like structures with high aspect ratios. Fourier transform infrared (FTIR) spectra indicated that trimethyl quaternary ammonium salt groups were introduced to the cellulose backbone during etherification. AH-NC had a much lower maximum decomposition temperature (T_max) than HH-NC or US-NC. The starch/HH-NC film exhibited the best water vapor barrier properties because the HH-NC particles were well-dispersed in the starch matrix, as demonstrated by the surface morphology of the film. Our results suggest that cationic NC is a promising reinforcing agent for the development of starch-based biodegradable food-packaging materials.

One-Pot Processing of Regenerated Cellulose Nanoparticles/Waterborne Polyurethane Nanocomposite for Eco-friendly Polyurethane Matrix

Regenerated cellulose nanoparticles (RCNs) reinforced waterborne polyurethanes (WPU) were developed to improve mechanical properties as well as biodegradability by using a facile, eco-friendly approach, and introducing much stronger chemical bonding than common physical bonding between RCNs and WPU. Firstly, RCNs which have an effect on improving the solubility and stability of a solution, thereby resulting in lower crystallinity, were fabricated by using a NaOH/urea solution. In addition, the stronger chemical bond between RCNs and WPU was here introduced by regarding at which stage in particular added RCNs worked best on strengthening their bond in the process of WPU synthesis. The chemical structure, mechanical, particle size and distribution, viscosity, and thermal properties of the resultant RCNs/WPU nanocomposites were investigated by Fourier transform infrared analysis (FTIR), Zeta-potential analysis, viscometer, thermogravimetric analysis (TGA), Instron, and dynamic mechanical analysis (DMA). The results of all characterizations indicated that the RCNs/WPU-DMF associated with the addition of RCNs in DMF-dispersed step resulted in more effectively crosslinked between WPU and nano-fillers of nanocellulose particles in the dispersion than Acetone and Water-dispersed steps, thereby attributing to novel interactions formed between RCNs and WPU.

Preparation of nanocellulose from Imperata brasiliensis grass using Taguchi method

Cellulose nanoparticles (CNs) were prepared by acid hydrolysis of the cellulose pulp extracted from the Brazilian satintail (Imperata Brasiliensis) plant using a conventional and a total chlorine free method. Initially, a statistical design of experiment was carried out using Taguchi orthogonal array to study the hydrolysis parameters, and the main properties (crystallinity, thermal stability, morphology, and sizes) of the nanocellulose. X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), zeta potential and thermogravimetric analysis (TGA) were carried out to characterize the physical-chemical properties of the CNs obtained. Cellulose nanoparticles with diameter ranging from 10 to 60 nm and length between 150 and 250 nm were successfully obtained at sulfuric acid concentration of 64% (m/m), temperature 35 °C, reaction time 75 min, and a 1:20 (g/mL) pulp-to-solution ratio. Under this condition, the Imperata Brasiliensis CNs showed good stability in suspension, crystallinity index of 65%, and a cellulose degradation temperature of about 117 °C. Considering that these properties are similar to those of nanocelluloses from other lignocellulosics feedstocks, Imperata grass seems also to be a suitable source for nanocellulose production.

Synergy in food, energy and advanced materials production from biomass

Biomass is a sustainable alternative to fossil fuels, as a source of energy and raw materials for industry. However, this is often criticized, based on an alleged competition with food production due to the presumed scarcity of agricultural land. Data from Brazil and Ethiopia show that the creation and dissemination of new agricultural technology actually allows a significant increase in the production of food as well as energy and raw materials from biomass, bringing economic, social and environmental benefits. Moreover, polymers from biomass display unique features that make them suitable as the basis for making advanced materials, with desirable combinations of chemical and physical properties required for some applications. For instance, natural rubber and cellulose have been used to create new complex nanostructured solids capable of performing new functions. Biomass can thus be exploited as a source of new materials as well as petrochemical-like building blocks.

Preparation of antimicrobial hybrid nano-materials using regenerated cellulose and metallic nanoparticles

In this study, antimicrobial hybrid nano-materials were prepared by one-pot syntheses of silver (Ag), copper oxide (CuO), or zinc oxide (ZnO) nanoparticles (NPs) during regeneration of cellulose from cotton linter (CL) and microcrystalline cellulose (MCC). SEM micrographs indicated that the metallic nanoparticles were attached to the surface of the regenerated cellulose. EDX and ICP results showed that more AgNPs were adsorbed on the cellulose than CuONPs or ZnONPs. FTIR results revealed that the metallic nanoparticles were attached to the cellulose through the interaction with the hydroxyl group of cellulose. XRD results showed the characteristic diffraction peaks of individual metallic nanoparticles. The thermal stability of the R-CL and R-MCC increased in the hybrids with AgNPs and ZnONPs. The R-cellulose/metallic NPs hybrids showed strong antibacterial activity against E. coli and L. monocytogenes. Thus, the hybrid nano-materials can be used as nanofillers for the preparation of antibacterial packaging films.

Untreated wheat straw: potential source for diverse cellulolytic enzyme secretion by Penicillium janthinellum EMS-UV-8 mutant

Study describes the production of cellulases by Penicillium janthinellum EMS-UV-8 using untreated wheat straw (WS), treated WS (acid, alkali, steam exploded, organo-solv) and pure cellulosic substrates (avicel, cellulose-II and carboxymethyl cellulose). Severely pretreated WS and cellulose-II produced more cellulolytic enzymes than untreated samples. XRD and FTIR analysis revels that the increase in the amorphous structure of pretreated WS/cellulose increases enzyme production. Enzyme samples prepared using different substrates were used for the hydrolysis of dilute acid treated wheat straw (DATWS), steam exploded wheat straw (SEWS) and avicel. The enzyme prepared using untreated WS gave more hydrolysis of DATWS and SEWS than the enzyme prepared using pretreated WS or pure cellulosic substrates. This revels that more diverse/potential enzymes were secreted by P. janthinellum EMS-UV-8 mutant using untreated WS. This study may contribute in production of efficient enzyme mixture/cocktail by single fungal strain for economic conversion of biomass to sugars.

Adhesive and Reinforcing Properties of Soluble Cellulose: A Repulpable Adhesive for Wet and Dry Cellulosic Substrates

This work reports, for the first time, the excellent performance of an aqueous alkaline solution of cellulose as an adhesive for wet and dry cellulosic substrates. Uniaxial tensile tests of filter paper and sulfite writing paper strips bonded with this adhesive (5% cellulose and 7% NaOH aqueous solution) show that failure never occurs in the joints but always in the pristine substrate areas, except in butt joint samples prepared with sulfite paper. Tensile test also shows that paper impregnated with cellulose solution is stronger than the original substrate. X-ray microtomography and scanning electron microscopy reveal that dissolved cellulose fills the gaps between paper fibers, providing a morphological evidence for the mechanical interlocking adhesion mechanism, while scanning probe techniques provide a sharp view of different domains in the joints. Additionally, bonded paper is easily reconverted to pulp, which facilitates paper reprocessability, solving a well-known industrial problem related to deposition of adhesive aggregates (stickies) on the production equipment.

Enhanced enzymatic hydrolysis of cellulose in microgels

A cellulose-based microgel, where an individual microgel contains approximately one cellulose chain on average, is synthesized via free radical polymerization of a difunctional small-molecule N,N'-methylenebisacrylamide in cellulose solution. This microgelation leads to a low-ordered cellulose, favoring enzymatic hydrolysis of cellulose to generate glucose.

Fabrication of cellulose-based aerogels from waste newspaper without any pretreatment and their use for absorbents

Cellulose-based aerogel (CBA) was prepared from waste newspaper (WNP) without any pretreatment using 1-allyl-3-methyimidazolium chloride (AmImCl) as a solvent via regeneration and an environmentally friendly freeze-drying method. After being treated with trimethylchlorosilane (TMCS) via a simple thermal chemical vapor deposition process, the resulting CBAs were rendered both hydrophobic and oleophilic. Successful silanization on the surface of the porous CBA was verified by a variety of techniques including scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and water contact angle (WCA) measurements. As a result, the silane-coated, interconnected CBAs not only exhibited good absorption performance for oils (e.g., waste engine oil), but also showed absorption capacity for organic solvents such as chloroform (with a representative weight gain ranging from 11 to 22 times of their own dry weight), making them diversified absorbents for potential applications including sewage purification.

Production of cellulose nanocrystals via a scalable mechanical method

Conversion of cellulose microfibers into nanocrystals.

The aggregation behavior of cellulose micro/nanoparticles in aqueous media

Cellulose micro/nanoparticles were obtained from cotton microcrystalline cellulose. The effect of ionic strength on the aggregation behavior of the cellulose micro/nanoparticles in aqueous media has been investigated by means of rheo-SALS.