Water-soluble Cellulose Research Articles

Internal Structure of Methylcellulose Fibrils

Methylcellulose (MC) is a water-soluble cellulose derivative with a wide range of commercial applications. Upon heating, MC solutions reversibly form ∼15–20 nm diameter fibrils, which percolate int...

The effects of leaf litter chemistry and anatomical traits on the litter decomposition rate of Quercus frainetto Ten. and Quercus cerris L. in situ

This paper presents the results of a one-year decomposition experiment on Quercus frainetto Ten. and Quercus cerris L. leaf litter in natural conditions. The decomposition rate constant was 0.831 yr?1 (Q. frainetto) and 0.458 yr?1 (Q. cerris). For the initial chemical composition of the oaks? litter, differences were not found in concentrations of lignin and fats, waxes and oil fractions, but were found for water-soluble matter, hemicellulose and cellulose. Later decomposition stages indicated that lignin and fats, waxes and oil fractions influenced differences in both oaks? litter decay rates. Anatomical analysis revealed differences between the oaks in leaf mesophyll and epidermis but not in the entire leaf and lower epidermis. Results after 12 months of the experiment revealed that 48.04% of the entire leaf, 53.30% of mesophyll, 32.93% of lignified upper and 47.67% of lower epidermis in Q. frainetto, and 28.70% of the entire leaf, 31.60% of mesophyll, 25.17% of lignified upper and 20.93% of lower epidermis in Q. cerris were decomposed. Reduction in leaf thickness mainly was caused by the reduction of mesophyll parenchyma, composed of easily degradable plant materials. Leaf tissues with the most recalcitrant plant materials were lignified upper epidermis, covered by a thick cuticle composed of fats and waxes, and xylem within the leaf veins.

Enhanced production of cellulosic butanol by simultaneous co-saccharification and fermentation of water-soluble cellulose oligomers obtained by chemical hydrolysis

Butanol attracted interests as a drop-in biofuel obtainable from cellulosic wastes. However, the process typically used for cellulose bioconversion, i.e., separate hydrolysis and fermentation (SHF) of pretreated cellulose (Process I), is insufficient for energy-efficient production of fuel grade butanol due to the limited obtainable butanol titer. Recently, post-hydrolysis of chemically formed water-soluble cellulose oligomers was suggested for acetone-butanol-ethanol (ABE) production in SHF mode of operation (Process II). In this study, it was found that simultaneous saccharification and fermentation of the soluble oligomers (oligomeric-SSF) (Process III) and simultaneous co-saccharification and fermentation (SCSF) of soluble oligomers along with regenerated cellulose (Process IV) are promising alternatives for upgrading the titer and yield of cellulosic butanol production by Clostridium acetobutylicum. In Process III, utilizing the oligomeric hydrolysate obtained through dilute acid hydrolysis at 120 °C for 60 min using 1% acid through oligomeric-SSF led to 14.2 g/L ABE production, i.e., 65% higher than Process I. In addition, using the oligomeric hydrolysate in SCSF resulted in 24 g/L ABE (16 g/L butanol) production with an overall yield of 182 g ABE/kg cellulose. Process IV showed 191% higher titer and 14% higher yield of ABE production, compared with Process I.

Eco-friendly fabrication of porous carbon monoliths from water-soluble carboxymethyl cellulose for supercapacitor applications

An eco-friendly method for the preparation of porous carbon monoliths (PCMs) with a high surface area and excellent electrochemical performance was demonstrated. Porous carboxymethyl cellulose monoliths (CMCMs) were prepared by ice-templating technique. PCMs were fabricated by the carbonization of ice-templated porous CMCMs. The prepared PCMs exhibited a high specific surface area of 724.35m2g–1 with multi-modal pore structures. The PCM-based electrode showed a high specific capacitance of 210Fg–1 at 1Ag–1 in a 6.0MKOH electrolyte, and an excellent cycle stability of almost 100% at 10Ag–1 after 10,000 cycles. Therefore, the PCMs prepared in this study are a promising electrode material for high-performance supercapacitors.

Partially Acetylated Cellulose Dissolved in Aqueous Solution: Physical Properties and Enzymatic Hydrolysis.

Cellulose acetate is one of the most important cellulose derivatives. The use of ionic liquids in cellulose processing was recently found to act both as a solvent and also as a reagent. A recent study showed that cellulose dissolution in the ionic liquid 1-ethyl-3-methylimidazoliumacetate (EMIMAc) mixed with dichloromethane (DCM) resulted in controlled homogenous cellulose acetylation; yielding water-soluble cellulose acetate (WSCA). This research investigated the properties of cellulose acetate prepared in this manner, in an aqueous solution. The results revealed that WSCA fully dissolves in water, with no significant sign of molecular aggregation. Its conformation in aqueous solution exhibited a very large persistence length, estimated as over 10 nm. The WSCA exhibited surface activity, significantly reducing the surface tension of water. Because of the molecular dissolution of WSCA in water, augmented by its amphiphilicity, aqueous solutions of WSCA exhibited an overwhelmingly high rate of enzymatic hydrolysis.

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Emulsion Formation and Stabilization by Biomolecules: The Leading Role of Cellulose.

Emulsion stabilization by native cellulose has been mainly hampered because of its insolubility in water. Chemical modification is normally needed to obtain water-soluble cellulose derivatives. These modified celluloses have been widely used for a range of applications by the food, cosmetic, pharmaceutic, paint and construction industries. In most cases, the modified celluloses are used as rheology modifiers (thickeners) or as emulsifying agents. In the last decade, the structural features of cellulose have been revisited, with particular focus on its structural anisotropy (amphiphilicity) and the molecular interactions leading to its resistance to dissolution. The amphiphilic behavior of native cellulose is evidenced by its capacity to adsorb at the interface between oil and aqueous solvent solutions, thus being capable of stabilizing emulsions. In this overview, the fundamentals of emulsion formation and stabilization by biomolecules are briefly revisited before different aspects around the emerging role of cellulose as emulsion stabilizer are addressed in detail. Particular focus is given to systems stabilized by native cellulose, either molecularly-dissolved or not (Pickering-like effect).

Fabrication of folate‐phytosterol‐carboxymethyl cellulose nanoparticles derived from plant material as carrier of anticancer drug

In this work, folate-phytosterol-carboxymethyl cellulose nanoparticles (FPCMC NPs) derived from plant material were fabricated and investigated as carrier of hydrophobic anticancer drugs. Firstly, hydrophobic phytosterol was grafted onto the framework of water-soluble carboxymethyl cellulose. Then folate, as tumor-targeting ligand, was coupled to the phytosterol-carboxymethyl cellulose to become self-assembled FPCMC NPs. The physicochemical properties of the fabricated FPCMC NPs were characterized. Doxorubicin (DOX) was selected as model anticancer drug that was entrapped in prepared FPCMC NPs with satisfactory loading content (7%) and loading efficiency (71.2%). The in vitro drug release test showed that the release amount of DOX from drug-loaded FPCMC NPs at pH 5.3 was much higher than that at pH 6.5 or pH 7.4. The research results indicated that the fabricated FPCMC NPs had the potential as nanocarrier of hydrophobic anticancer drugs for further experimental study.

Controlled Release of Glucose from Orally Delivered Temperature- and pH-Responsive Polysaccharide Microparticle Dispersions

Dual-responsive polysaccharide microgel dispersions were synthesized by the self-assembly of a temperature-responsive water-soluble cellulose ether, hydroxypropyl cellulose (HPC), and a pH-responsi...

Magnetic nano carboxymethyl cellulose-alginate/chitosan hydrogel beads as biodegradable devices for controlled drug delivery

For the first time, nano carboxymethyl cellulose (NCMC) was synthesized via cellulose nanocrystal carboxymethylation. This nanomaterial was magnetized and used in bilayer alginate-chitosan hydrogel beads formulation to develop eco-friendly, smart, and magnetic sensitive hydrogel beads for the controlled pH-sensitive release of dexamethasone as a model drug. Water-soluble nanocrystalline cellulose (NCMC) and bilayer hydrogel beads were characterized in terms of size, surface morphology, surface modification, crystallinity, drug loading content, and in vitro drug release profile using various technics. Furthermore, the swelling behavior of hydrogels was examined and reported in three buffer media. The NCMCs improved drug loading capacity and swelling properties and also regulated drug release behavior of hydrogels. The hydrogel beads swelling specification exhibited a higher index in phosphate buffer at pH 5.8 than at pH 1.2 and 7.4. Besides, in vitro release of beads revealed excellent pH-sensitive drug release profiles and prevented release in the gastrointestinal tract. The beads showed high pH sensitivity for dexamethasone drug in pH 5.8 in compared to other pH media. The obtained results could introduce hydrogel beads as a high potential drug delivery system.

Water-Soluble Cellulose Derivatives as Suitable Matrices for Multifunctional Materials.

This work reports on a simple and environmentally benign route to prepare freestanding magnetic films based on cellulose derivatives through the combination of cobalt ferrite (CoFe2O4) nanoparticles with methyl cellulose (MC), hydroxypropyl cellulose (HPC), and sodium carboxymethyl cellulose (NaCMC). Nanoparticles are able to "shield" hydrogen bonding interactions between polysaccharide chains and lower the viscosity of water-dissolved MC, HPC, and NaCMC, allowing an easy film fabrication. Crack-free films with homogeneously dispersed nanoparticles having concentrations up to 50 wt % are fabricated by mechanical agitation followed by doctor blade casting. All of the nanocomposite films keep a substantial level of flexibility with elongation at break exceeding 5%. Halpin-Tsai equations serve to provide further insights on the character of matrix-CoFe2O4 interfaces. Magnetization saturation increases almost linearly with cobalt ferrite concentration up to a maximum value of ∼24-27 emu g-1 for nanocomposites containing 50 wt % of nanoparticles. The dielectric response of the films demonstrates a strong dependence on both the functional groups attached to the main cellulose chain and the ferrite nanoparticle content. The renewable character of the hosting matrices, together with the fabrication methods that solely uses water as a solvent, the decrease of the viscosity with the inclusion of fillers, particularly suitable for printable materials, and the resulting magnetic performance provide novel avenues for the replacement of traditional magnetoactive composites based on petroleum-derived polymers and avoiding the use of toxic solvents.

Synthesis of folate mediated carboxymethyl cellulose fatty acid ester and application in drug controlled release

An amphiphilic polymer, carboxymethyl cellulose-laurate (CMC-C12), was synthesized by esterification of water-soluble carboxymethyl cellulose (CMC) and hydrophobic lauroyl chloride. Folate, a cancer-cell-specific ligand, was conjugated to CMC-C12 to obtain folate-CMC-C12 (FA-CMC-C12) which could be targeted to folate-receptor-overexpressing cancer cells. FA-CMC-C12 was characterized by Fourier transform infrared (FT-IR) spectra and nuclear magnetic resonance (NMR). The amphiphilic polymer, FA-CMC-C12, can self-assemble into micelles with spherical morphology. The anticancer drug doxorubicin (DOX) was entrapped inside FA-CMC-C12 micelles. The sustained release of DOX was studied in phosphate buffered saline (PBS) at pH 5.6. It indicates that the drug release rates of DOX is about 85% with excess β-cyclodextrin (β-CD) which far exceed the drug release rates of DOX without β-CD.

Efficient Removal of Lead from Water Using Stabilized Iron Sulfide Nanoparticles: Effectiveness and Effects of Stabilizer

Fully stabilized FeS nanoparticles were prepared with water-soluble carboxymethyl cellulose (CMC) as a stabilizer, and investigated for adsorption of lead (Pb2+) ions from simulated drinking water. The optimum particle stabilization was achieved using 0.0025 wt.% of CMC for 50 mg/L FeS (i.e., CMC-to-FeS molar ratio of 0.0005). The particle stabilization technique increased lead removal from 78.1% to 90.3%. However, further increasing the CMC-to-FeS molar ratio to 0.0025 diminished the removal. Rapid adsorption kinetics of Pb by CMC-FeS was observed with an equilibrium time of 240 min. The kinetic data was adequately fitted by a pseudo-second-order kinetic model. The adsorption isotherm showed a sigmoidal S-shape due to complexation of Pb with soluble CMC molecules, and the Sigmoidal isotherm model well fitted the adsorption isotherm data with a maximum monolayer adsorption capacity of 77.0 mg/g. FTIR and XRD analyses indicated that both surface complexation and chemical precipitation (in the form of PbS) were the dominant adsorption mechanisms. Pb uptake was enhanced with increasing CMC-FeS dosage from 10 to 125 mg/L and increasing pH from 4.5 to 8.5. The material can perform well under typical concentrations of a model humic acid (HA) and salts. Yet, unusually high concentrations of HA or hardness ions may exerted elevated inhibitive effect. The findings indicated that CMC-stabilized FeS nanoparticles are promising for effective immobilization of lead in contaminated water and soil.

Enzymatic post-hydrolysis of water-soluble cellulose oligomers released by chemical hydrolysis for cellulosic butanol production

A process consisting of regeneration of crystalline cellulose, dilute-phosphoric acid hydrolysis of regenerated cellulose to soluble oligomers, and enzymatic post-hydrolysis of soluble oligomers in the absence of disturbing solid particles was evaluated as a process alternative for upgrading the obtainable sugar concentration and facilitating the long-term enzymatic hydrolysis of cellulose by utilizing soluble oligomers instead of insoluble particles. Cellulose was regenerated though phosphoric acid-acetone process, i.e., dissolution into 21 g/g acid at 50 °C for 60 min and precipitation by adding 41 g/g acetone. Regenerated cellulose was hydrolyzed at 120, 150 or 180 °C for 30 or 60 min using 0.5 or 1% phosphoric acid. After filtration, the hydrolysates were subjected to 10 or 15 FPU/g cellulase. Dilute-acid hydrolysis of regenerated cellulose with 0.5% acid at 180 °C, 30 min, and 10% solid loading resulted in an “oligomeric hydrolysate” with 44.6 g/L soluble oligomers. Enzymatic post-hydrolysis of soluble oligomers resulted in a “monomeric hydrolysate” containing as high as 47 g/L glucose and cellobiose. In the hydrolysis, 429 g sugar was released at high concentration from one kg crystalline cellulose. The hydrolysates were subjected to fermentation by Clostridium acetobutylicum, where oligomeric hydrolysates showed poor fermentability. The fermentation of monomeric hydrolysates obtained by dilute-acid hydrolysis (120 °C, 60 min, and 0.5% acid) and post-hydrolysis (15 filter paper unit/g) resulted in 6.1 g/L acetone–butanol–ethanol. Besides other potential advantages, this hydrolysis approach resulted in relatively high concentration of glucose which may facilitate cellulosic butanol production.

Direct Electrospinning of Cellulose Acetate onto Polyurethane Sheet and Effect of Its Saponification on Mechanical Properties

This article reports on direct electrospinning of water-soluble cellulose acetate (WSCA) and cellulose diacetate (CDA) onto a non-conductive synthetic polymer sheet such as polyurethane (PU) sheet to modify its surface morphology. The direct electrospinning was successfully performed after spraying an anti-static agent on the PU sheet. Furthermore, tight fixation of the fibers was achieved by spraying a dimethylformamide/ethanol (1/1) solution during the spinning. Finally, the cellulose acetate fibers on the PU sheet were converted to regenerated cellulose fibers by saponification. Changes in surface morphology were evaluated via tribology tests. The friction coefficient of the PU sheet significantly decreased with increases in the amount of deposited fiber, thereby suggesting that the PU sheet surface became smoother. After saponification, the friction coefficients of the sheets slightly increased, with the exception of the PU sheet with the increased amount of saponified WSCA fibers, and this was potentially attributed to changes in the elasticity upon saponification.

Low-cost and robust production of multi-doped 2D carbon nanosheets for high-performance lithium-ion capacitors

Consumer electric vehicles, portable electronic devices, future energy-storage systems, and large-scale grid storage are urgently demanding in the novel devices for bridging-the-gap between high energy density and power density. Carbon nanosheets (CNS)-based energy-storage systems are ideal candidates because of their exotic electronic properties, shortened ion transport paths, and large electrochemical active surfaces. Herein, we propose a facile approach to fabricate boron, oxygen and nitrogen multi-doped 2D CNS from viscous organic precursors (VOPs) and apply them as an anodic material of lithium-ion capacitors (LICs). Through rapid thermal expansion of the cellulose-rich VOPs at an intermediate temperature of 550 °C, the mass production of CNS with high specific surface area and abundant active sites are achieved. When the prelithiated CNS anode is coupled with an active carbon (AC) cathode using water-soluble carboxymethyl cellulose lithium (CMCLi) binder, the obtained 4.5 V green hybrid LIC device delivers a high energy density of 203.6 Wh kg−1 at a power density of 225.0 W kg−1, a high power density of 22.5 kW kg−1 (achieved at 119.8 Wh kg−1), and a reasonably good cycle performance (≈84.5% retention after 5000 cycles at 2 A g−1). This work offers an opportunity to apply the CNS in green LICs, with predominant balance in energy and power density, high working voltage and long cycle life.

SOFTs – Structured orodispersible film templates

Orodispersible films (ODFs) have a high potential to accelerate the individualized medication. The films can be produced as drug-free templates and subsequently printed with an API (active pharmaceutical ingredient) solution or suspension according to the needs of the patient. While the printing technology already enables a precise dosing of fluids, there is still a high need of suitable, edible templates with elevated loading capacity. The structured orodispersible film templates (SOFTs) developed in this study should overcome this void. The SOFTs are pervaded with pores to realize a high API load into the film structure and possess a closed bottom side to prevent the printed fluids to pass through the film. They consist of a water-soluble cellulose derivative and are produced with the solvent casting method.This study focused on the influence of the formulation of the film casting mass on the film properties, like porosity and disintegration time due to changed pore sizes and numbers. Due to the porous film structure a mass load of up to 6.1 mg cm−2 could be realized already in SOFTs, but, higher loads are feasible. The mechanical film properties could further be improved by additional matrix material in the suspension formulation, also inhibiting particle agglomeration and aggregation during the drying process, and positively influencing the dissolution behavior of the applied nanoparticles. An application of a protection layer on top of the loaded SOFTs improves the handling safety by inhibiting contact to the API and it prevents a removal of the particles from the film surface.

Short-term steam treatment of MFC gel with and without water-soluble cellulose derivative

Abstract Microfibrillated cellulose (MFC) with and without added CMC was exposed to short-term dynamic thermal treatment using a steam jet cooker. The effects of the elevated temperature (130 °C, ∼3 bar) and shear forces on the rheology, crystallinity index, UV/VIS adsorption and water retention were measured. Jet cooking increased the viscosity and gel strength of the MFC and MFC/CMC mixture but with CMC alone a slight decrease in viscosity was observed. The water retention capacity and crystalline indices of the MFC were not greatly affected by the short-term thermal treatment and shear forces, although a slight increase in the UV/VIS absorbance was observed.

Polymer Distribution and Mechanism Conversion in Multiple Media of Phase-Separated Controlled-Release Film-Coating.

Phase-separated films of water-insoluble ethyl cellulose (EC) and water-soluble hydroxypropyl cellulose (HPC) can be utilized to tailor drug release from coated pellets. In the present study, the effects of HPC levels and the pH, type, ionic strength and osmolarity of the media on the release profiles of soluble metoprolol succinates from the EC/HPC-coated pellets were investigated, and the differences in drug-release kinetics in multiple media were further elucidated through the HPC leaching and swelling kinetics of the pellets, morphology (SEM) and water uptake of the free films and the interaction between the coating polymers and the media compositions. Interestingly, the drug release rate from the pellets in different media was not in agreement with the drug solubility which have a positive correlation with the drug dissolution rate based on Noyes–Whitney equation law. In particular, the drug release rate in acetate buffer at pH 4.5 was faster than that in other media despite the solubility of drug was relatively lower, regardless of the HPC levels. It may be attributed to the mutual effect between the EC and acetate buffer, which improved the permeability of the film. In contrast, the release of drug in HCl solution was dependent on the HPC levels. Increasing the levels of HPC increased the effects of hydrogen ions on the polymer of HPC, which resulted in a lower viscosity and strength of the gel, forming the larger size of pores in polymer films, thus increasing the drug diffused from the coating film. Further findings in phosphate buffer showed a reduction in the drug release compared to that in other media, which was only sensitive to the osmolarity rather than the HPC level and pH of the buffer. Additionally, a mathematical theory was used to better explain and understand the experimentally measured different drug release patterns. In summary, the study revealed that the effects of the media overcompensated that of the drug solubility to some extent for controlled-release of the coating polymers, and the drug release mechanism in multiple media depend on EC and HPC rather than on HPC alone, which may have a potential to facilitate the optimization of ideally film-coated formulations.

Fabrication and performance characterization of the membrane from self-dispersed gelatin-coupled cellulose microgels

A new gelatin-coupled cellulose (GCC) microgel system was successfully prepared in NaOH/urea aqueous solution with epichlorohydrin (ECH) as a coupling agent via dialysis and self-dispersion pathway. The structure and property of the microgel and its membrane were characterized by elemental analysis, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectra, gel permeation chromatography (GPC), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was concluded that successful coupling interactions occurred between cellulose and gelatin during the fabrication process, and the weight-average molecular weight of GCC microgel was up to 636.60 kDa with polydispersity index (PDI) of 1.015 approximately. The crystalline structure of the modified cellulose was destroyed, leading to GCC product self-dispersed in water in the absence of NaOH and urea. The GCC microgels had whisker-like structure, and their Z-average particle sizes were approximately 86.1 nm–150.2 nm and decreased with the increases of the gelatin content (WGel). In comparison with the water contact angle, swelling behavior and thermostability of the existing water-soluble cellulose derivative, the microgel membranes exhibited better water resistance and thermal resistance properties.