Water-soluble Carboxymethyl Cellulose Research Articles

Creating value added nano silicon anodes from end-of-life photovoltaic modules: recovery, nano structuring, and the impact of ball milling and binder on its electrochemical performance

Recovery of silicon from end-of-life photovoltaic (PV) modules, purification, conversion to nano silicon (nano-Si), and subsequent application as an anode in lithium-ion batteries is challenging but can significantly influence the circular economy. Currently, a complete technology consisting of cross-contamination-free recovery of silicon wafers from end-of-life PV modules, a low-cost environmentally friendly purification process of the recovered PV silicon, a high yield conversion process of the recovered PV silicon into nano-Si, and its subsequent application in lithium-ion batteries is unavailable. This study provides a complete package including cross-contamination-free recovery, economical purification, reliable conversion to nano-Si, and efficient application of the end-of-life PV nano-Si in lithium-ion batteries. Hydrofluoric acid-free recovery and purification processes are demonstrated which can deliver large quantities of high-purity (≥ 99) silicon. In addition, the subsequent ball milling process produces very distinct nano-Si with different shapes and sizes. This study also creates a very effective nano-Si anode through in-situ crosslinking of water-soluble carboxymethyl cellulose and poly (acrylic acid) precursors. The integration of distinct PV nano-Si and water-soluble carboxymethyl cellulose-poly (acrylic acid) crosslink binder opens distinct possibilities to develop silicon-based practical anode for next generation low-cost lithium-ion batteries to power cell phones to electric vehicles.

Carboxylmethyl cellulose produced from wood sawdust for improving properties of sodium alginate hydrogel in dye adsorption

Cellulose-based materials have shown immense potential for diverse applications because of their attractive properties such as excellent mechanical properties, rich hydroxyl groups for modification, and natural properties with recyclability, nontoxicity, biocompatibility, biodegradability, and environmental friendliness. This study aimed to optimize cellulose extraction from wood sawdust using deep eutectic solution (DES) treatments for the preparation of carboxymethyl cellulose (CMC) and to evaluate the application of CMC in sodium alginate (SA) microgel for dye adsorption. Cellulose extractions were optimized in reduced chemical treatment conditions with high cellulose contents (88.19 %), and selectively increased lignin removal (87.23 %). The analyses by SEM, XRD, and FT-IR revealed that carboxymethylation has successfully transformed cellulose into CMC to facilitate the significantly improved water solubility and swelling ability. The TGA curve of CMC showed a higher thermal stability (residual weight of 52 % at 300 °C) compared to unmodified cellulose due to the decomposition of the amorphous regions during the carboxymethylation. The combined biodegradable SA and water-soluble CMC composite microgels were successfully fabricated via cross-linking with calcium chloride using a microfluidic approach. The incorporation of CMC into SA microgel had enhanced mechanical properties, adsorption capacities of 160.87 and 141.48 mg/g, and adsorption–desorption efficiencies of 96.84 % and 95.41 % for crystal violet and trypan blue respectively after five cycles. The adsorption processes of both dyes can be described by Sips adsorption isotherms and pseudo-second-order kinetic models, verifying the chemical interaction-assisted process. This simple green CMC/SA adsorbent has the potential to significantly enhance the adsorption capacity of dye removal from wastewater.

Carbonization of Corn Leaf Waste for Na-Ion Storage Application Using Water-Soluble Carboxymethyl Cellulose Binder.

Hard carbon materials are considered to be the most practical anode materials for sodium ion batteries because of the rich availability of their resources and potentially low cost. Here, the conversion of corn leaf biomass, a largely available agricultural waste, into carbonaceous materials for Na-ion storage application is reported. Thermal analysis investigation determines the presence of exothermic events occurring during the thermal treatment of the biomass. Accordingly, various temperatures of 400, 500, and 600 °C are selected to perform carbonization treatment trials, leading to the formation of various biocarbons. The materials obtained are characterized by a combination of methods, including X-ray diffraction, electron microscopy, surface evaluation, Raman spectroscopy, and electrochemical characterizations. The Na-ion storage performances of these materials are investigated using water-soluble carboxymethyl cellulose binder, highlighting the influence of the carbonization temperature on the electrochemical performance of biocarbons. Moreover, the influence of post-mechanochemical treatment on the Na-ion storage performance of biocarbons is studied through kinetic evaluations. It is confirmed that reducing the particle sizes and increasing the carbon purity of biocarbons and the formation of gel polymeric networks would improve the Na-ion storage capacity, as well as the pseudocapacitive contribution to the total current. At a high-current density of 500 mA g-1, a specific Na-ion storage capacity of 134 mAh g-1 is recorded on the biocarbon prepared at 600 °C, followed by ball-milling and washing treatment, exhibiting a reduced charge transfer resistance of 49 Ω and an improved Na-ion diffusion coefficient of 4.8 × 10-19 cm2 s-1. This article proposes a simple and effective technique for the preparation of low-cost biocarbons to be used as the anode of Na-ion batteries.

(Digital Presentation) Water-Soluble Binders That Enhance Electrochemical Sodium-Ion Storage Properties of NaTi2(PO4)3 Nanoparticle Anodes

Sodium ion batteries (SIBs) have been considered as one of the most promising alternative to conventional lithium-ion batteries (LIBs) for next generation energy storage systems.1 , 2 In terms of anodes, commercial graphite only delivers a sodium-ion storage capacity of 31 mAh g−1.3 The polyanionic-type NaTi2(PO4)3 material is an attractive anode because of the crystal structure of a Na-super-ionic conductor (NASICON), high theoretical capacity, safety characterization and ‘zero-stress’ framework upon sodiation/desodiation.4 , 5 The primary role played by the binder is to link different types of small particles together and to ensure the active material adheres to the current collector, which has an important contribution to the electrical and mechanical behaviour of the electrode.6 , 7 Poly(vinylidene fluoride) (PVDF) is a common organic binder using N-methyl-2-pyrrolidone (NMP) as solvents. Sodium carboxymethyl cellulose (CMC) has been considered as an effective and green water-soluble binders. Styrene butadiene rubber (SBR) typically serves as an elastomer in water-soluble CMC binders and further increases binding force, adhesion, heat resistance, and flexibility of an electrode. The role of different binders on the structural/chemical stability of NaTi2(PO4)3 anode in SIBs has rarely been studied.Here, we synthesized NaTi2(PO4)3 nanoparticles using the hydrothermal method and explore the effects and influence of PVDF, CMC and CMC-SBR binders on the sodium-ion storage performance of NaTi2(PO4)3 anodes. Compared to traditional organic PVDF binder, water-soluble binders improved the cycling stability by increasing adhesion, flexibility, and mechanical properties between the active materials, conductive addictive and current collector. Notably, water-soluble binders show an important effect on the sodium storage mechanism of NaTi2(PO4)3 nanoparticles. The addition of SBR in the water-soluble binders further enhances the active materials areal specific capacity because of its better adhesion ability, reducing the overall quantity of binder polymer required for the electrode. This novel exploration of the effective combination of water-soluble CMC and SBR binders for NaTi2(PO4)3 anodes in SIBs not only provides an opportunity to enhance their electrochemical sodium storage properties, but may enables their practical application in high areal energy density sodium ion batteries in the future. References (1) Nayak, P. K.; Yang, L.; Brehm, W.; Adelhelm, P.: From Lithium-Ion to Sodium-Ion Batteries: Advantages, Challenges, and Surprises. Angew. Chem. Int. Ed. 2018, 57, 102-120.(2) Kim, S.-W.; Seo, D.-H.; Ma, X.; Ceder, G.; Kang, K.: Electrode Materials for Rechargeable Sodium-Ion Batteries: Potential Alternatives to Current Lithium-Ion Batteries. Adv. Energy Mater. 2012, 2, 710-721.(3) Doeff, M. M.; Ma, Y.; Visco, S. J.; De Jonghe, L. C.: Electrochemical insertion of sodium into carbon. J. Electrochem. Soc. 1993, 140, L169-L170.(4) Delmas, C.; Cherkaoui, F.; Nadiri, A.; Hagenmuller, P.: A nasicon-type phase as intercalation electrode: NaTi2(PO4)3. Mater. Res. Bull. 1987, 22, 631-639.(5) Chen, S.; Wu, C.; Shen, L.; Zhu, C.; Huang, Y.; Xi, K.; Maier, J.; Yu, Y.: Challenges and Perspectives for NASICON-Type Electrode Materials for Advanced Sodium-Ion Batteries. Adv. Mater. 2017, 29, 1700431.(6) Chen, H.; Ling, M.; Hencz, L.; Ling, H. Y.; Li, G.; Lin, Z.; Liu, G.; Zhang, S.: Exploring Chemical, Mechanical, and Electrical Functionalities of Binders for Advanced Energy-Storage Devices. Chem. Rev. 2018, 118, 8936-8982.(7) Bommier, C.; Ji, X.: Electrolytes, SEI Formation, and Binders: A Review of Nonelectrode Factors for Sodium-Ion Battery Anodes. Small 2018, 14, 1703576. Figure 1 (a) SEM image and (b) HRTEM image of NaTi2(PO4)3 nanoparticles with quasi-cubic architecture and hollow structure. (c) XRD analysis of the synthesized nanoparticles. (d) Specific capacity versus rate data using chronoamperometry (CA) method for NaTi2(PO4)3 nanoparticles anode of different binders. (Inset) Corresponding digital photos for NTP electrodes with different binders. (e) The first cycle in the cyclic voltammetric curve at a scan rate of 0.1 mV s-1 for NaTi2(PO4)3 nanoparticles anode. (f) Galvanostatic discharging and charging cycling stability at 0.2 C (1C = 133 mA g-1) for the NaTi2(PO4)3 nanoparticle anode with different binders. Figure 1

Effects of Conductive Agents on Electrochemical Performance of Water-Based LiNi<sub>0.6</sub>Mn<sub>0.2</sub>Co<sub>0.2</sub>O<sub>2</sub> Cathodes for Cylindrical Cell Production of Lithium-Ion Batteries

Lithium-ion batteries have received much attention for their potential use in electric vehicles (EV's) and portable electronic devices. Fabrication of lithium ion (Li-ion) batteries via ecologically sound (green) processes is also of great interest. Typically, in the production of cathode electrodes, organic solvents such as N-methyl-pyrrolidone (NMP) are used, but these chemicals are toxic. Water-based processing of LiNi0.6Mn0.2Co0.2O2 (NMC) for manufacturing cathode electrodes can provide a more environmental friendly option. In this work, water soluble styrene butadiene copolymer (SBR) and carboxymethyl cellulose (CMC) are used as binders. The active material ratio was set at 90%. The electrochemical performance of water-based NMC electrodes is examined. Additionally, various conductive agents were considered including acetylene black (A) and graphite (B). The particle sizes of conductive agent affect the electrochemical performance of the batteries. Our results show that replacing the conventional organic solvent-based manufacturing route for NMC cathodes with a water-based process is a promising way to fabricate Li-ion batteries with comparable electrochemical behavior, while avoiding toxic process materials and simultaneously reducing the overall manufacturing costs.

Li-incorporated porous carbon monoliths derived from carboxymethyl cellulose as anode material for high power lithium-ion batteries

In this study, a simple and effective pre-lithiation strategy is developed to resolve a large initial irreversible capacity loss and low initial Coulombic efficiency of porous carbon as anode material for Li-ion batteries. By using this strategy, Li-incorporated hierarchically porous carbon monoliths (PCMs) are successfully obtained from water-soluble carboxymethyl cellulose lithium salt. The prepared PCMs are found to have amorphous carbon structures and well-developed hierarchical pore architectures. In addition, Li is found to be homogeneously incorporated throughout the prepared PCMs. The electrochemical properties of the prepared Li-incorporated PCMs are studied in a half-cell configuration and exhibit lower initial irreversible capacity along with stable cycle life at high current densities. Generally, the resistance of LIB cell remarkably increases at the end of discharge. Here, the galvanostatic intermittent titration technique analyses reveal a higher diffusion coefficient of the prepared Li-incorporated PCMs, specifically at the end of discharge. Therefore, this inherent property of Li-incorporated PCMs is favorable for high-power LIB anode materials.

Cellulose from oil palm empty fruit bunch fiber and its conversion to carboxymethylcellulose

AbstractBACKGROUNDHigher‐value products, such as cellulose and carboxymethylcellulose (CMC), may be produced from lignocellulosic agroindustrial residues, such as oil palm empty fruit bunch (EFB) fibers that are presently underutilized or discarded. Recovery of cellulose from EFB and its conversion of CMC are discussed as methods of creating value and reducing the environmental impact of EFB.RESULTSCellulose was recovered from EFB fibers and converted to water soluble CMC. Cellulose isolation used a two‐step sequential treatment involving peracetic acid (PA) (50 g dry EFB L−1 PA, 35 °C, 9 h) for initial delignification, and then alkaline peroxide (AP) (50 g delignified‐EFB L−1 AP, 45 °C, 12 h). This treatment removed 91.5% of lignin in the original EFB fiber. The recovered solids, designated as cellulose‐EFB, were comprised of 83.7 ± 3.4% cellulose, 5.6 ± 0.3% hemicellulose, 1.7 ± 0.0% lignin, and 1.7 ± 0.1% ash. A two‐step process with an initial alkalization {3 g cellulose‐EFB in 99 mL solvent [10:1 by vol mixture of ethanol (95%) and 35% NaOH], 30 °C, 2 h} followed by etherification was used to convert cellulose‐EFB to CMC sodium salt. The conversion yield was 50% of the theoretical maximum.CONCLUSIONThe best conditions for preparing CMC from cellulose‐EFB were a 2 h treatment with 35% (wt/vol) NaOH during alkalization at 30 °C, followed by etherification at 55 °C. The CMC had a degree of substitution of 0.16 and a water solubility of 6.8 g L−1 at 30 °C. © 2021 Society of Chemical Industry

Low And Highly Substituted Carboxymethyl Cellulose Synthesis From Powdered And Microcrystalline Cellulose

The conditions for low and highly substituted water-soluble carboxymethyl cellulose synthesis based on microcrystalline and powder cellulose by the suspension method have been investigated. Accordingly, it was obtained CMC water-soluble samples with 0.38-0.40 substitution degree based on microcrystalline and powder cellulose. And at one stage, there were obtained CMC samples with a high degree of substitution (1.4) by carboxymethylation so called polyanionic cellulose.

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.

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.

Effect of aqueous solutions of Carboxymethyl Cellulose on draining time in gravity driven flow

The time for gravity draining of water from a large Cylindrical open tank by means of a drain pipe ( Located at the center of the bottom of the storage tank) is measured experimentally for the case of turbulent flow conditions in the drain pipe. Further, to reduce draining time, experiments are also conducted by the addition of water soluble Carboxymethyl Cellulose (CMC). The concentrations of CMC considered are 0.625,1.25, 2.5 and 5ppm respectively. The optimum concentration of CMC is found to be 0.625 ppm. Further, the re-usability of CMC polymer solutions is also contemplated and it is noted that there is an increase in draining time upon re-use of the CMC polymer solutions.

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.

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.

Preparation of self‐regulating/anti‐adhesive hydrogels and their ability to promote healing in burn wounds

Few burn dressings can self-regulate the optimal humidity levels that are required for wound healing, while also providing good anti-adhesive properties to prevent damage that can occur when wound dressings are changed. Consequently, a water-soluble carboxymethylcellulose sodium/sodium alginate/chitosan (CMC-Na/SA/CS) composite hydrogel has been developed as a potential burn wound dressing, with orthogonal testing revealing an optimal ratio of CMC-Na, SA, and CS as 2, 3, and 1 wt % for hydrogel preparation, respectively. The resultant hydrogel has been formulated into composite wound dressings that were then used for the treatment of deep second degree burn wounds in Sprague-Dawley (SD) rats. Analysis of the physical properties of this dressing revealed that it exhibits good water vapor permeability properties that promote the healing of deep second-degree burn wounds. The pro-healing mechanism of the dressing has been investigated Vascular endothelial growth factor (VEGF) expression was upregulated and basic fibroblast growth factor (bFGF) expression was downregulated in the early periods of wound healing, with upregulation of bFGF then occurring at a later stage of wound healing. At the same time, the wound dressing decreased the levels of tumor necrosis factor-α and interleukin-6, thus validating its beneficial effect on the wound healing process at a biomolecular level. In conclusion, this new hydrogel dressing was shown to exhibit excellent self-regulatory and anti-adhesive properties that synergistically promote the healing of burn wounds in rats, thus providing promising results that may have clinical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1471-1482, 2019.

Fabrication of Stabilized Fe⁻Mn Binary Oxide Nanoparticles: Effective Adsorption of 17β-Estradiol and Influencing Factors.

Fe–Mn binary oxide nanoparticles (FMBON) were reported to be high performance as adsorbent for pollutants removal from aqueous solution. However, there are still limitations in practice application due to the FMBON tend to aggregate into the micro millimeter level. In order to avoid the agglomeration of nanoparticles, this work synthesized the stabilized Fe–Mn binary oxide nanoparticles (CMC-FMBON) by using water-soluble carboxymethyl celluloses (CMC) as the stabilizer. The characteristics of CMC-FMBON and FMBON were measured by using Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Zeta potential. This work systematically investigated the adsorption capacity of CMC-FMBON for 17β-estradiol (E2) and the influences of external environmental factors on E2 removal. The results indicated that CMC-FMBON had much smaller particles, wider dispersion and larger surface area than the FMBON. CMC-FMBON showed better adsorption performance for E2 than FMBON with the maximum adsorption capacity of CMC-FMBON and FMBON were 124.10 and 98.14 mg/g at 298 K, respectively. The experimental data can be well fitted by the model of pseudo-second-order and Langmuir model. The E2 removal by CMC-FMBON was obviously dependent on pH with the maximum adsorption occurring when the pH was acidic. The removal capacity of CMC-FMBON increased when enhancing ionic strength in solution. Background electrolytes promoted slightly E2 adsorption process whereas the presence of humic acid inhibited the E2 removal. π-π interactions, hydrogen bonds, and oxidation might be responsible for E2 removal. This research suggested that the CMC-FMBON has been considered to be a cost-efficient adsorbent for removing E2 from water.

The structure of galactoglucomannan impacts the degradation under alkaline conditions

Galactoglucomannan (GGM) from spruce was studied with respect to the degradation behavior in alkaline solution. Three reference systems including galactomannan from locust bean gum, glucomannan from konjac and the linear water-soluble carboxymethyl cellulose were studied with focus on molecular weight, sugar composition, degradation products, as well as formed oligomers, to identify relative structural changes in GGM. Initially all mannan polysaccharides showed a fast decrease in the molecular weight, which became stable in the later stage. The degradation of the mannan polysaccharides could be described by a function corresponding to the sum of two first order reactions; one slow that was ascribed to peeling, and one fast that was connected with hydrolysis. The galactose side group was stable under conditions used in this study (150 min, 90 °C, 0.5 M NaOH). This could suggest that, apart from the covalent connection to C6 in mannose, the galactose substitutions also interact non-covalently with the backbone to stabilize the structure against degradation. Additionally, the combination of different backbone sugars seems to affect the stability of the polysaccharides. For carboxymethyl cellulose the degradation was linear over time which further suggests that the structure and sugar composition play an important role for the alkaline degradation. Molecular dynamics simulations gave details about the conformational behavior of GGM oligomers in water solution, as well as interaction between the oligomers and hydroxide ions.

Simultaneous analysis of uric acid, xanthine and hypoxanthine using voltammetric sensor based on nanocomposite of palygorskite and nitrogen doped graphene

Abnormal level of purines, especially uric acid (UA), xanthine (XA) and hypoxanthine (HX) in organisms is an important marker for early diagnosis of animal (human) disease. In this paper, an simultaneous analysis of UA, XA and HX in biological samples was successfully realized using the fabricated voltammetric sensor based on the nanocomposite of both nano-rod clay mineral palygorskite (Pal) and two-dimensional nano-layered nitrogen doped graphene (NG). A water-soluble carboxymethyl cellulose (CMC) salt was simultaneously decorated both Pal and NG to improve the water dispersibility, and their nanocomposite was characterized. Under optimized conditions, The as-prepared nanocomposite electrode (CMC-Pal-NG/GCE) could realize their simultaneous voltammetric analysis in linear ranges from 0.5 to 60μM for UA, 0.2 to 20μM for XA, and 0.6 to 55μM for HX. The limit of detection of three purines (UA,XA and HX) is calculated to be 0.1 for UA, 0.05 for XA and 0.4μM for HX, and their possible detailed mechanisms for electro-catalytic oxidation and chemical reaction was discussed, which was successfully empolyed for simultaneous voltammetric analysis of three purines in real samples with good reproducibility, repeatability and stability. Satisfactory results indicated that the obtained nanocomposite will provide a promising candidate for the simultaneous electrochemical determination of UA, XA and HX in analysis of practical samples.

Interactions between wheat starch and cellulose derivatives in short-term retrogradation: Rheology and FTIR study

The understanding of the interactions between starch and cellulose hydrocolloids is crucial for equipment design and definition of operation parameters in the food industry. In the present study, the possible interactions of wheat starch (WS) with different levels (2–10%) of carboxymethyl cellulose (CMC) or microcrystalline cellulose (MCC) in short-term retrogradation were explored by dynamic rheological and Fourier transform infrared spectrum (FTIR) measurements. The chains of water-soluble CMC could creep into the continuous phase during paste gelation. It was found the amylose network structure was broken and the inter- and intra-molecular hydrogen bond of WS were weaken after gelation. Moreover, there were interactions between the chains of CMC and chains of amylose at higher CMC concentration. On other hand, water connected with COO− groups blocked the interactions between CMC chains and amylose, and the interactions among CMC chains. The amorphous phases of high crystalline MCC were just swollen during paste gelation. It results that heterogeneous microstructure with amylose and MCC domains unevenly distributed was in WS/MCC paste.

Bio-Based Artificial Nacre with Excellent Mechanical and Barrier Properties Realized by a Facile In Situ Reduction and Cross-Linking Reaction.

Demands for high strength integrated materials have substantially increased across various kinds of industries. Inspired by the relationship of excellent integration of mechanical properties and hierarchical nano/microscale structure of the natural nacre, a simple and facile method to fabricate high strength integrated artificial nacre based on sodium carboxymethylcellulose (CMC) and borate cross-linked graphene oxide (GO) sheets has been developed. The tensile strength and toughness of cellulose-based hybrid material reached 480.5 ± 13.1 MPa and 11.8 ± 0.4 MJm-3 by a facile in situ reduction and cross-linking reaction between CMC and GO (0.7%), which are 3.55 and 6.55 times that of natural nacre. This hybrid film exhibits better thermal stability and flame retardancy. More interestingly, the hybrid material showed good water stability compared to that in the original water-soluble CMC. This type of hybrid has great potential applications in aerospace, artificial muscle, and tissue engineering.