Ordinary Cellulose Research Articles

Revisiting oxidation and reduction reactions for synthesizing a three-dimensional hydrogel of reduced graphene oxide.

An improvement to Hummers' method involving a cascade-design graphite oxidation reaction is reported to optimize safety and efficiency in the production of graphite oxide (GrO) and graphene oxide (GO). Chemical reduction using highly alkaline ammonia solution is a novel approach to synthesizing reduced graphene oxide (RGO). In this original research, we revisit the oxidation and reduction reactions, providing significant findings regarding the synthetic pathway to obtain a bioinspired water-intercalated hydrogel of RGO nanosheets. Influential factors in the graphite oxidation reaction, typically the exothermic reaction temperature and hydrogen peroxide effect, are described. Furthermore, the chemical reaction of GO reduction using highly alkaline ammonia solution (pH 14) was investigated to produce hydrated RGO nanosheets assembled in a hydrogel structure (97% water). Three-dimensional assembly and water intercalation are key to preserve the non-stacking state of RGO nanosheets. Therefore, ultrasound transmission to aqueous channels in the macroscopic RGO hydrogel vibrated and dispersed the RGO nanosheets in water. Analytical results revealed the single-layer nanostructures, functional groups, optical band gaps, optimized C/O ratios, particle sizes and zeta potentials of GO and RGO nanosheets. The reversible self-assembly of RGO hydrogels is essential for many applications, such as RGO coatings and polymer/RGO nanocomposites. In a water purification application, the RGO hydrogel was dispersed in aqueous solution by simple agitation and showed a high capacity for organic dye adsorption. After the adsorption, the RGO/dye particles were easily removed by filtration through ordinary cellulose paper. The process of adsorption and filtration is effective and inexpensive for practical environmental remediation. In summary, a bioinspired structure of RGO hydrogel is conceptualized for prospective nanotechnology.

Antimicrobial and hydrophobic cellulose paper prepared by covalently attaching cinnamaldehyde for strawberries preservation

The demand for paper-based packaging materials as an alternative to incumbent disposable petroleum-derived polymers for food packaging applications is ever-growing. However, typical paper-based formats are not suitable for use in unconventional applications due to inherent limitations (e.g., excessive hydrophilicity, lack antimicrobial ability), and accordingly, enabling new capabilities is necessity. Herein, a simple and environmentally friendly strategy was proposed to introduce antimicrobial and hydrophobic functions to cellulose paper through successive chemical grafting of 3-aminopropyltriethoxysilane (APS) and cinnamaldehyde (CA). The results revealed that cellulose paper not only showed long-term antibacterial effect on different bacteria, but also inhibited a wide range of fungi. Encouragingly, the modified paper, which is fluorine-free, displays a high contact angle of 119.7°. Thus, even in the wet state, the modified paper can still maintain good mechanical strength. Meanwhile, the multifunctional composite papers have excellent biocompatibility and biodegradability. Compared with ordinary cellulose paper, multifunctional composite paper can effectively prolong the shelf life of strawberries. Therefore, the multifunctional composite paper represents good application potential as a fruit packaging material.

Electrochromic Displays Screen Printed on Transparent Nanocellulose‐Based Substrates

Manufacturing of electronic devices via printing techniques is often considered to be an environmentally friendly approach, partially due to the efficient utilization of materials. Traditionally, printed electronic components (e.g., sensors, transistors, and displays) are relying on flexible substrates based on plastic materials; this is especially true in electronic display applications where, most of the times, a transparent carrier is required in order to enable presentation of the display content. However, plastic‐based substrates are often ruled out in end user scenarios striving toward sustainability. Paper substrates based on ordinary cellulose fibers can potentially replace plastic substrates, but the opaqueness limits the range of applications where they can be used. Herein, electrochromic displays that are manufactured, via screen printing, directly on state‐of‐the‐art fully transparent substrates based on nanocellulose are presented. Several different nanocellulose‐based substrates, based on either nanofibrillated or nanocrystalline cellulose, are manufactured and evaluated as substrates for the manufacturing of electrochromic displays, and the optical and electrical switching performances of the resulting display devices are reported and compared. The reported devices do not require the use of metals and/or transparent conductive oxides, thereby providing a sustainable all‐printed electrochromic display technology.

Synthesis and characterization of new insensitive and high-energy dense cellulosic biopolymers

In the present study, microcrystalline cellulose carbamate nitrate (MCCCN) and ordinary cellulose carbamate nitrate (OCCN) as a new class of insensitive and high-energy dense polymers were successfully synthesized for the first time through a simple efficient procedure. Carbamate-functionalized cellulose and cellulose microcrystals (OCC and MCCC) were firstly prepared from their precursors using chlorosulfonyl isocyanate (CSI) as carbamate agent. After that, the nitration of functionalized and non-functionalized cellulosic precursors with concentrated sulfonitric mixtures was undertaken. Their physico-chemical features, molecular structure, thermal behavior, and mechanical sensitivity features were determined, and compared to those of the common nitrocellulose and emergent microcrystalline cellulose nitrate (OCN and MCCN). Furthermore, the detonation properties of the developed energetic polymers were evaluated using Explo5 (V6.04) computer code. The findings of this study confirm the efficiency of the performed surface modification approach to produce insensitive MCCCN and OCCN with excellent features such as density of 1.687 g/cm3 and 1.703 g/cm3, explosion energy of 5040 kJ/kg and 5334 kJ/kg, and detonation velocity of 7613 m/s and 7785 m/s, respectively, which are better than those of the conventional nitrocellulose. This work provides a novel and sustainable pathway to prepare new insensitive energetic polymers with outstanding physicochemical properties and energetic performances from renewable cellulose, which may further promote the functional application of cellulose and open the way of cellulose-based energetic materials for explosive formulations and high-performance propellants.

Cellulose Nanofibrils-based Hydrogels for Biomedical Applications: Progresses and Challenges.

Cellulose Nanofibrils (CNFs) are natural nanomaterials with nanometer dimensions. Compared with ordinary cellulose, CNFs own good mechanical properties, large specific surface areas, high Young's modulus, strong hydrophilicity and other distinguishing characteristics, which make them widely used in many fields. This review aims to introduce the preparation of CNFs-based hydrogels and their recent biomedical application advances. By searching the recent literatures, we have summarized the preparation methods of CNFs, including mechanical methods and chemical mechanical methods, and also introduced the fabrication methods of CNFs-based hydrogels, including CNFs cross-linked with metal ion and with polymers. In addition, we have summarized the biomedical applications of CNFs-based hydrogels, including scaffold materials and wound dressings. CNFs-based hydrogels are new types of materials that are non-toxic and display a certain mechanical strength. In the tissue scaffold application, they can provide a micro-environment for the damaged tissue to repair and regenerate it. In wound dressing applications, it can fit the wound surface and protect the wound from the external environment, thereby effectively promoting the healing of skin tissue. By summarizing the preparation and application of CNFs-based hydrogels, we have analyzed and forecasted their development trends. At present, the research of CNFs-based hydrogels is still in the laboratory stage. It needs further exploration to be applied in practice. The development of medical hydrogels with high mechanical properties and biocompatibility still poses significant challenges.

Fabrication of Copper Nano- Filter Membrane and its use in the Purification of Contaminated Water

Copper nanoparticles were synthesised by the green method using African spinach and peppermint leaves extract as both reducing and capping agents. The synthesized nanoparticles were then characterized by Energy Dispersive Spectroscopy, (EDS), Scanning Electron Microscopy (SEM) and Fourier Transform Infra-Red Spectroscopy (FTIR). EDS confirmed the formation of copper nanoparticles and SEM images showed spherical nanoparticles with an average size of 3.44 μm. FTIR showed that the functional groups on the leaves’ extracts were capped on the surface of the nanoparticles. The nanoparticles were then casted into a nano- filter membrane using cellulose actetate and used to filter contaminated water gotten from a canal at the University of Lagos. The filtration efficiency of this nano-filter was compared with the ordinary cellulose acetate membrane and the result showed that the copper nano-filter membrane gave an odorless, cleaner water than that of ordinary cellulose acetate membrane. The microbial analysis also revealed that about 96.5 % of the bacteria was removed using the copper nano-filter membrane.

Preparation of Antibacterial and Deodorizing composite regenerated cellulose fibers based on natural functional agents

The regenerated cellulose fibers with antimicrobial and deodorizing functions were prepared by wet spinning process by blending the extract of Artemisia argyi and activated clay powder into the spinning solution. The mechanical properties and antimicrobial and deodorizing functions were tested. The results show that the breaking strength and breaking elongation rate of the composite fibers are slightly lower than those of ordinary cellulose fibers. The inhibition rate of Staphylococcus aureus, Escherichia coli and Candida albicans were 95%, 81% and 83% respectively, and the reduction rates of ammonia, acetic acid and isovaleric acid were 80%, 95% and 78%, respectively. It has excellent antimicrobial and deodorizing performance.

Unraveling Escherichia coli's Cloak: Identification of Phosphoethanolamine Cellulose, Its Functions, and Applications.

Bacterial biofilms are complex, multicellular communities made up of bacteria enmeshed in a self-produced extracellular matrix (ECM) that protects against environmental stress. The ECM often comprises insoluble components, which complicates the study of biofilm composition, structure, and function. Wrinkled, agar-grown Escherichia coli biofilms require 2 insoluble macromolecules: curli amyloid fibers and cellulosic polymers. We quantified these components with solid-state nuclear magnetic resonance (NMR) and determined that curli contributed 85% of the isolated uropathogenic E coli ECM dry mass. The remaining 15% was cellulosic, but, surprisingly, was not ordinary cellulose. We tracked the identity of the unanticipated peak in the 13C NMR spectrum of the cellulosic component and discovered that E coli secrete phosphoethanolamine (pEtN)-modified cellulose. Cellulose is the most abundant biopolymer on the planet, and this marked the first identification of a naturally, chemically modified cellulose. To investigate potential roles of pEtN cellulose, we customized a newly designed live-cell monolayer rheometer and demonstrated that pEtN cellulose facilitated E coli attachment to bladder epithelial cells and acted as a glue, keeping curli cell associated. The discovery of pEtN cellulose opens questions regarding its biological function(s) and provides opportunities in materials science to explore this newly discovered biopolymer.

Technology of Recycling, Properties and Use of Polyvinylchloride-Coated Paper Waste

The technology of recycling of polymer-coated paper waste is described. Physical and chemical properties of fibers obtained from wallpaper wastes and from their derivative compositions were investigated. A special crusher with primary and secondary grinding stages and with a section for separating paper fibers from polymer coating was designed. Industrial trials of cellulose obtained from wallpaper wastes for the asbestos cement sheets manufacturing were held. Its impact on the quality and physical and mechanical properties of sheets was shown. Methods of thermogravimetry, microscopy, and differential thermal, infrared spectral and chemical analysis were applied to investigate cellulose fibers derived from recycled wallpaper. Their properties were compared to the ordinary cellulose and polyvinylacetate fibers, which are used in the production of asbestos cement sheets.

Mixture Screening Design to Choose Formulations for Functionally Graded Fiber Cements

This work employing the screening strategy to examine thirteen mix proportions of six-component fiber cement formulations composed of ordinary Portland cement, ultra-fine cement, limestone filler, silica fume, cellulose and polyvinyl alcohol fibers. The vacuum de-watering technique was applied in the production of fiber cement specimens cured for 10 days and submitted to four-point bending tests. The mechanical properties such as limit of proportionality (LOP), modulus of elasticity (MOE), modulus of rupture (MOR) and specific energy (SE) were evaluated and these properties were correlated with the raw material fractions resulting in mixture rules. Results indicate that screening can be a promising methodology with which to generate coherent fiber cement mixture rules, optimize formulations in terms of costs and performance and even facilitate the choosing of formulations for functionally graded fiber cements.

Preparation and Properties of Enterosorbents Based on Carboxylated Microcrystalline Cellulose

Features of a non-traditional method of preparation of cellulose-based cation-exchange enterosorbents using nitrogen (IV) oxide are discussed. The proposed approach involves sequential use of oxidative and acid-hydrolyzing functions of nitrogen (IV) oxide to convert ordinary cellulose into carboxylated microcrystalline cellulose. X-ray phase analysis and transmission electron microscopy data show evidence of a topochemical character of cellulose microcrystal modification with carboxyl groups. Factors are indicated causing enhanced stability and whiteness of the samples thus obtained as compared with oxidized cellulose fibres, as well as the ease of stable tixotropic gel formation from the samples prepared in a salt form. Exemplified by methylene blue sorption, a comparative assessment of the sorptive ability of enterosorbent powders and hydrogels prepared in acid and salt forms. Results of clinical trials conducted with the gel enterosorbents in the areas of gastroenterology and detoxication therapy are presented. In view of compatibility of carboxylated microcrystalline cellulose in hydrogel form with many biologically active ingredients, prospective character of using the enterosorbents not only as such but also as a matrix for the development of new dosage forms of other medications is pointed out. Examples showing advantages of such combinations in specific sustained release drug forms (ointments and microgranules) are given.

Preparation and properties of cellulose/chitin blend fiber

AbstractThe blend solution of cellulose xanthate with chitin xanthate has excellent filtering property as an ordinary cellulose viscose. The SEM photos show that the fiber surface becomes coarse with increasing chitin content. The X‐ray diffraction shows that the addition of chitin interferes with the crystallization of cellulose. The dry and wet strength and density of blend fibers decrease with increasing chitin content. The hygroscopicity of the blend staples decreases with increasing chitin content, and there exists a minimum at 3.85% chitin mass percent, while the accessibility shows the same tendency. The fiber prepared has effective bacteriostatic effects on Staphylococcus aureus, Escherchia coli, etc., and the bacteriostastic rate increases with increasing chitin content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3430–3436, 2003

Composites of bacterial cellulose and paper made with a rotating disk bioreactor.

Suspended solids in the nutrient medium for Acetobacter xylinium in a rotating disk bioreactor become incorporated into the gelatinous mat of bacterial cellulose as it forms. Embedding fibers of ordinary cellulose creates composites with enhanced strength and the toughness of bacterial cellulose. Purified cellulose and elongated fibers from paper are incorporated differently than are spherical particles such as silica gel. About 90% of the final cellulose can come from scrap paper, and dried composite sheets were much stronger than plain bacterial cellulose per unit area.

Abnormal lipid metabolism and oxidative stress in hemodialysis patients

Oxidative stress is enhanced in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). Bioincompatibility represents an important source of reactive oxygen species. HD patients exhibit altered antioxidative defenses, and antioxidative vitamins such as vitamin E and C are altered in uremia. Frequently, HD patients also suffer from atherosclerotic cardiac disease. We previously reported that low-density lipoprotein (LDL) of HD patients is rich in malondialdehyde (MDA), an end product of lipid peroxidation. MDA-rich LDL is thought to be an atherogenic lipoprotein because of its enhancement of macrophage foam-cell formation. We conducted a controlled study for 2 years comparing the effects of a vitamin E-coated cellulose membrane dialyzer and an ordinary cellulose membrane dialyzer on lipid metabolism and the progress of atherosclerosis. LDL MDA and oxidized LDL (ox-LDL) were measured in HD patients by using these two types of dialyzers. Plasma vitamin E and lipid concentrations were also evaluated. Aortic calcification index (ACI) was evaluated by CT scan to assess the progress of atherosclerosis before and every year after initiation of the treatment. The use of a vitamin E-coated cellulose membrane dialyzer for 6 months, 1 year, and 2 years resulted in a significant reduction in LDL-MDA and ox-LDL compared with that obtainal with the use of the ordinary cellulose membrane dialyzer. The treatment with a vitamin E-coated dialyzer significantly reduced the percent increase in ACI after 24 months as compared with control. There were no significant differences in plasma vitamin E and lipid concentrations between the two groups. These results suggest that oxidative stress could be one of the factors stimulating abnormal lipid metabolism and atherosclerosis in ESRD patients.

Effect of vitamin E on lipid metabolism and atherosclerosis in ESRD patients

Oxidative stress is enhanced in patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD). Bioincompatibility represents an important source of reactive oxygen species. HD patients exhibit altered anti-oxidative defences and anti-oxidative vitamins such as vitamin E and C are altered in uremia. Frequently, HD patients also suffer from atherosclerotic cardiac disease. We have previously reported that low density lipoprotein (LDL) of HD patients is rich in malondialdehyde (MDA), an end product of lipid peroxidation. MDA rich LDL is thought to be an atherogenic lipoprotein due to its enhancement of macrophage foam cell formation. We conducted a controlled study for two years comparing the effects of a vitamin E coated cellulose membrane dialyzer and an ordinary cellulose membrane dialyzer on lipid metabolism and the progress of atherosclerosis. LDL-MDA and oxidized LDL (ox-LDL) were measured in HD patients using these two types of dialyzers. Plasma vitamin E and lipid concentrations were also evaluated. The aortic calcification index (ACI) was evaluated by CT scan to assess the progress of atherosclerosis before and for every year after treatment. Use of a vitamin E coated cellulose membrane dialyzer for six months, one year and two years resulted in a significant reduction in LDL-MDA and ox-LDL compared to the ordinary cellulose membrane dialyzer. Treatment with a vitamin E-coated dialyzer significantly reduced the percentage increase in ACI after 24 months compared to the control. There were no significant changes in plasma vitamin E and lipid concentrations between the two groups. These results suggest that the oxidative stress could be one of the stimulating factors of abnormal lipid metabolism and atherosclerosis in ESRD patients.

Computer Aided Time-Lapse Video Analysis of Hepatocyte Morphology during Adhesion to Cellulose Membranes

An investigation was performed to demonstrate that time-lapse cinematography and computer aided video analysis of cell morphology is suitable to study and compare the characteristics of hepatocytes during the adhesion process to membranes. We chose to compare ordinary cellulose Cuprophan membranes and membranes coated with collagen or fibronectin. Striking differences between uncoated cellulose and fibronectin or collagen coating were seen in the cell count per square millimeter and adhesion behaviour. On the investigated uncoated Cuprophan the hepatocytes were found to attach but not to spread whilst on collagen coated Cuprophan most of the cells spread spherically, and on fibronectin coated membranes most of the cells flattened spherically or polygonally. Time-lapse video microscopy seems to be a valuable technique for assessing the morphologic behaviour of cells in a detailed and quantitative manner in order to improve the hepatocyte culture technique in bioreactors for hybrid systems.

Removal of Ruthenium from PUREX Process, (II) Fundamental Research of Electrolytic Oxidation of Ruthenium

A new method was developed for the removal of ruthenium from nitric acid solutions. Ruthenium in 3 M nitric acid solution is oxidized electrolytically to ruthenium tetraoxide, and the tetraoxide is extracted into n-paraffin. The ruthenium tetraoxide extracted in paraffin is readily reduced to ruthenium dioxide by the solvent as black suspension, and it can be easily filtered off through an ordinary cellulose fiber filter. By this method, ruthenium, one of the most troublesome fission elements in PUREX Process, can be removed.

Removal of ruthenium from PUREX process. (II). Fundamental research of electrolytic oxidation of ruthenium.

A new method was developed for the removal of ruthenium from nitric acid solutions. Ruthenium in 3 M nitric acid solution is oxidized electrolytically to ruthenium tetraoxide, and the tetraoxide is extracted into n-paraffin. The ruthenium tetraoxide extracted in paraffin is readily reduced to ruthenium dioxide by the solvent as black suspension, and it can be easily filtered off through an ordinary cellulose fiber filter. By this method, ruthenium, one of the most troublesome fission elements in PUREX Process, can be removed.

Removal of Ruthenium from PUREX Process

Ruthenium in nitric acid solution is oxidized by the addition of eerie nitrate to ruthenium tetroxide, which is extracted with n-paraffin oil. Ruthenium tetroxide in paraffin is immediately reduced by the solvent to black ruthenium dioxide as suspension, which can be readily filtered off through the ordinary cellulose filter paper. Through the combined process of extraction and filtration, the ruthenium in a nitric acid solution can be eliminated.

Removal of ruthenium from Purex process. Extraction of ruthenium tetroxide with paraffin oil and filtration of ruthenium dioxide.

Ruthenium in nitric acid solution is oxidized by the addition of eerie nitrate to ruthenium tetroxide, which is extracted with n-paraffin oil. Ruthenium tetroxide in paraffin is immediately reduced by the solvent to black ruthenium dioxide as suspension, which can be readily filtered off through the ordinary cellulose filter paper. Through the combined process of extraction and filtration, the ruthenium in a nitric acid solution can be eliminated.