Viscose Cellulose Research Articles

CuS Hollow Nanospheres/Cellulose Composite Film as a Recyclable Interfacial Photothermal Evaporator for Solar Steam Generation

Effective utilization of solar energy for the production of thermal energy is regarded as one of the most sustainable ways to conquer the growing global energy crisis. Photothermal conversion at the water–air interface is considered to be a promising route for steam generation, distillation, and desalination. However, most of the interfacial photothermal evaporators often require optical concentrators and complicated systems with multiple components, leading to poor efficiency and high cost. Herein, an extremely simple and low‐cost interfacial heating film for highly efficient solar steam generation is introduced. The composite film is composed of a viscose cellulose film loaded with CuS hollow nanospheres. The CuS/cellulose composite film, fabricated by a solvothermal method process, serves as an efficient solar absorber (>94%), vapor channel, and thermal insulator (the thermal conductivity is 0.06 W m−1 K−1), leading to an efficiency of 85% under solar irradiation (1.0 kW m−2), which represents a concrete step for solar steam generation to alleviate the global water scarcity.

Development of biopolymer-based menstrual pad and quality analysis against commercial merchandise

BackgroundManaging menstrual hygiene in the least developed countries represents a significant obstacle for women and girls. Commonly dirty stuffs are used to control the menstrual cycle which causes many diseases, while disposable hygiene-absorbent material during menstruation is an essential requirement. Most local commercial sanitary napkins offer high absorptiveness and flexibility; however, most of them, due to the use of synthetic superabsorbent polymer (SAP) within the core layer, are not biodegradable and harmful to human skin. This research aims to create a sanitized and biodegradable pad in order to replace SAP with environmentally sound biopolymer that give rural poor women competent performance and characteristics.ResultFor the construction of the model, some of the current sanitary pads from the local market are examined. Six models are designed using various biopolymers such as cotton, viscose, wood pulp, sodium alginate and carboxy methyl cellulose (CMC) in different proportions as the core absorbent layer to boost requirements such as absorption, fluid retention strength, coziness and cost reduction. The sanitized pads have gone through various investigations such as antimicrobial activity, wicking ability and water retention capacity to standardize vital features and value. The experimental results show the use of sodium alginate and CMC is a possible replacement for SAP as the best comparable result is observed in template consuming sodium alginate, CMC and cellulosic fibre. Non-woven fabric treated with neem extract forming the outer layer of sanitary napkin serving with antimicrobial activity of more than 90% against both gram-positive and gram-negative bacteria.ConclusionOutcomes recommend significant advancement and cost-effectiveness of the newly designed archetype. Sanitary napkins without SAP can be a safe disposal solution and can therefore have a sustainable environmental impact.

For ionic liquids, the time is now

On Finnish Independence Day in December 2018, Finland’s first lady, Jenni Haukio, wore a dress made from birch trees. No, she wasn’t covered in bark and leaves. The garment was woven from fibers made using a process, called Ioncell, developed by Aalto University and the University of Helsinki. The process uses ionic liquids such as 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enium acetate ([mTBDH][OAc]) to dissolve cellulose and extract it from wood pulp. The natural polymer is spun into fibers. Making fibers out of cellulose isn’t new. Viscose cellulose has been made since the 19th century in a cumbersome process requiring the harsh chemicals sodium hydroxide, carbon disulfide, and sulfuric acid. Ioncell, according to Herbert Sixta, a professor in Aalto’s Department of Bioproducts and Biosystems, is a simpler, closed-loop process with no chemical discharges. Aalto is building a pilot plant that will produce 10 kg of fiber per day when it opens

In Situ Synthesis of Au Nanoparticles on Viscose Cellulose Sponges for Antibacterial Activities.

Antibacterial viscose cellulose sponges (VCSs) were fabricated by heating cellulose xanthogenate (viscose) containing HAuCl4·nH2O. Viscose was used as the reducing agent and stabilizer for the in situ synthesis of Au nanoparticles (AuNPs) onto the VCSs. The morphology, structures, thermal properties, mechanical performance, and antibacterial activities of the sponges were investigated. Results indicate that AuNPs were uniformly immobilized in the VCSs, and the resulting complexes (AuNPs@VCSs) showed enhanced thermal stability and mechanical properties. Additionally, the AuNPs@VCSs exhibited remarkable antibacterial activities, with zone of inhibition diameter of 35.7 and 37.1 mm for Staphylococcus aureus and Escherichia coli, respectively. The process is simple and applicable at the industrial level and can be applied to the fields of cleaning and sanitation.

Recycling of pre-consumer viscose waste fibers for the removal of cationic dye from aqueous solution

Recycling of textile waste materials has attracted significant attention for fabrication low-cost dye adsorbent from aqueous solutions. Viscose cellulosic waste fibers are supposed to give an answer to the finding low-cost adsorbent materials. In this research work, viscose waste fibers (VF) were modified by selective oxidation to improve the ability to absorb cationic dyes during wastewater treatment. For this purpose, different treatment parameters were investigated such as sodium periodate concentration, and time of selective oxidation with sodium chlorite. Then, unmodified and oxidized viscose fibers (OVF) were ball milled to produce viscose powder (VP) and oxidized viscose powder (OVP), respectively. The morphology of obtained viscose powders was characterized by scanning electron microscopy. Furthermore, methylene blue adsorption onto viscose cellulose fiber waste (VF) and oxidized viscose fibers (OVF) was studied as a function of contact time (0–80 min), adsorbent dosage (1–9 g/L), MB solution initial pH (3–9) and MB initial concentration (20–80 mg/L). The results showed that MB adsorption onto VF and OVF is a rapid favorable chemisorption process that can be well described by the Langmuir model. The higher adsorption capacity of OVF than VF was related to the increase of the carboxylic group. The oxidized viscose fiber can be used as a potential adsorbent for water treatment.

A method of physicochemical treatment of the wood pulp based on cold refining

We develop a universal method of physicochemical refining of the market wood pulp to the level given by the requirements of State standards for fibrous semi-finished products for deep chemical processing into various functional derivatives and artificial materials (Na-CMC, colloxylin, pyroxylin, viscose and cordage fibers). An experimental laboratory modular setup was designed and manufactured at the Semenov Institute of Chemical Physics (RAS). The modification includes the following stages: preparation of the raw materials, chemical modification, washing, and drying of the final product. At the first stage the original market pulp was dispersed to obtain a homogeneous suspension, cleaned and dried. After washing, the refined cellulose was dried in two stages: i) microwave drying to a moisture content of 45 - 50%; ii) convective drying with warm air to a moisture content of 5 - 9%. The basis of chemical modification is the stage of cold refining. Compared to other methods of refining wood pulp (acid-alkali treatment, hot refining) cold refining does not require special equipment which operate at elevated temperature and pressure. The developed procedure of physicochemical modification of the market wood pulp is universal, since it has no restrictions on the brand of the initial raw material. Depending on the quality requirements to the final product, the proposed method provides obtaining all brand of cellulose for chemical processing — viscose cellulose, acetate cellulose, cord cellulose. Mass fraction of the alpha-cellulose in the final product ranges from 93 to 99%.

Influence of cellulose/[Bmim]Cl solution on the properties of fabricated NIPS PVDF membranes

In this study, composite membranes were prepared from mixed solution of polyvinylidene fluoride (PVDF) and cellulose via the non-solvent-induced phase separation (NIPS) method. N, N-dimethylacetamide (DMAc) and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) were used as the solvent for PVDF and cellulose, respectively. SEM and in situ scanning techniques were used to investigate the morphology of the prepared membranes. The results showed that viscose cellulose/[Bmim]Cl solution acted as a porogenic agent during the membrane preparation process. Hydrophilicity of the composites was evaluated by water contact angle, moisture regain and equilibrium water uptake, which demonstrated that the wettability of the membranes was associated with the hydrophilic group and the roughness of the surface. Most importantly, the α → β transformation in PVDF matrix was demonstrated from the results of WAXD, FT-IR and DSC. The quantitative analysis indicated that the β-phase content in PVDF reached 90.1% when cellulose content was 5%, which is higher than many published references and was ascribed to the cooperation of cellulose and ionic liquid. Besides, the crystallinity, thermal stability and mechanical properties of the composite membranes were studied as well.

Chitosan nanoparticles as a potential drug delivery system attached to viscose cellulose fibers

Chitosan and its water-soluble N,N,N-trimethyl derivative were attached to cellulose fibers in the form of nanoparticle dispersions. The attachment of the chitosan nanoparticles to the fiber surface was studied by evaluation of the quantity of chitosan amino groups using a conventional spectrophotometric method supported by X-ray photoelectron spectroscopy. The desorption kinetics of the chitosan nanoparticles from the fiber surface was also examined indirectly by the spectrophotometric method. Additionally, a model drug was incorporated into the optimal chitosan nanoparticles for subsequent attachment to fibers to create a potential fibrous drug delivery system aimed at gynecological use, i.e., tampons as antimicrobial agents themselves or as drug reservoirs.

Preparation of Hydrophobic Viscose Fabric Using Nitrogen DBD and Copper Ions Sorption

Plasma treatment of viscose cellulose fabric was performed using the atmospheric pressure dielectric barrier discharge (DBD) in nitrogen. Samples were treated using nonthermal plasma, and change of sorption properties with plasma energy density was investigated. It was found that using low energy of discharge, modified viscose samples become less hydrophilic and their wettability is significantly reduced. The observed hydrophobic effect was investigated and confirmed throughout series of experiments, by measuring a change in wetting time and in the level of aqueous liquid repellency. Structural changes were monitored using SEM, AFM, and XPS. It was established that increase of roughness combined with removal of hydrophilic polar groups from the surface of cellulose using plasma represents a novel approach to impart hydrophobicity onto hydrophilic textile. An additional binding of copper ions to nitrogen DBD treated cellulose produces a cross‐linking effect, i.e., an occupation of remaining hydrophilic groups on the fabric surface and provides so called “petal effect” where drops of water stick to the fabric surface when the fabric is tilted for 180°. This novel procedure for obtaining hydrophobic cellulose could be used for a preparation of special protective textile materials with cost and time effective methods and chemicals.

Synthesis and application of a formaldehyde-free flame retardant for bamboo viscose fabric

A formaldehyde-free flame retardant (EFFR) for bamboo viscose fabric was synthesized by raw materials of silanol, phosphorus pentoxide, and diethanolamine. The flame retardant had the dual function of imparting fire resistance and softness to bamboo viscose fabric; moreover, it had no halogen and free formaldehyde, and wouldn’t release formaldehyde during processing and end-use. The experimental results about choice of cross-linker stated that the cross-linker played a significant role in decreasing the flammability of bamboo viscose fabrics and improving durability of flame retardance. Cross-linkers of hexamethylol melamine (HMM) or dimethylol dihydroxy ethylene urea (DMDHEU) or water-soluble isocyanate-terminated (WIT) not only cross-linked with flame retardant and bamboo viscose cellulose to enhance durability of inflaming retarding, but also had nitrogen to improve nitrogen–phosphorus synergism. However, HMM and DMDHEU can release free formaldehyde. WIT is a kind of cross-linker which has no formaldehyde. The experimental results showed that the Limiting Oxygen Index (LOI) value of Vis-EFFR–WIT treated fabric was basically above 30%, and the handle of the finished fabric was ameliorated greatly because of its organosilyl constituent part, even after 30 laundry cycles, the fabric still had some flame retardancy and soft feeling.

Prospective study on burns treated with Integra®, a cellulose sponge and split thickness skin graft: Comparative clinical and histological study—Randomized controlled trial

BackgroundThe aim of this study was to compare three different methods to cover excised burn wounds in a randomized controlled trial. MethodsFascially excised burn wounds, measuring 10cm×5cm, were covered with Integra®, split thickness skin graft (STSG), and a viscose cellulose sponge Cellonex™ in each of ten adult patients. Integra® and Cellonex™ treated areas were covered with thin STSG on day 14. Biopsies were taken 3, 7, 14, and 21 days, 3 months, and 12 months after surgery, and samples were subjected to a range of immunohistochemical stains, in addition to hematoxylin and eosin (HE). Scar assessment was performed 3 and 12 months post-operatively with the Vancouver Scar Scale (VSS). ResultsInflammation was not substantial in any of the study areas, but Cellonex™ had the most neutrophils, histiocytes, and lymphocytes with significant differences on days 7 and 14. Complete vascularization of Integra® seemed to occur later compared to the other materials. STSG had the most myofibroblasts on day 14 (p=0.012). In VSS the quality of the scar improved in all materials from 3 to 12 months. ConclusionsThe final results for all treatments after 12 months demonstrate equal clinical appearance, as well as histological and immunohistochemical findings.

MMP-13 regulates growth of wound granulation tissue and modulates gene expression signatures involved in inflammation, proteolysis, and cell viability.

Proteinases play a pivotal role in wound healing by regulating cell-matrix interactions and availability of bioactive molecules. The role of matrix metalloproteinase-13 (MMP-13) in granulation tissue growth was studied in subcutaneously implanted viscose cellulose sponge in MMP-13 knockout (Mmp13 −/−) and wild type (WT) mice. The tissue samples were harvested at time points day 7, 14 and 21 and subjected to histological analysis and gene expression profiling. Granulation tissue growth was significantly reduced (42%) at day 21 in Mmp13 −/− mice. Granulation tissue in Mmp13 −/− mice showed delayed organization of myofibroblasts, increased microvascular density at day 14, and virtual absence of large vessels at day 21. Gene expression profiling identified differentially expressed genes in Mmp13 −/− mouse granulation tissue involved in biological functions including inflammatory response, angiogenesis, cellular movement, cellular growth and proliferation and proteolysis. Among genes linked to angiogenesis, Adamts4 and Npy were significantly upregulated in early granulation tissue in Mmp13−/− mice, and a set of genes involved in leukocyte motility including Il6 were systematically downregulated at day 14. The expression of Pdgfd was downregulated in Mmp13 −/− granulation tissue in all time points. The expression of matrix metalloproteinases Mmp2, Mmp3, Mmp9 was also significantly downregulated in granulation tissue of Mmp13 −/− mice compared to WT mice. Mmp13 −/− mouse skin fibroblasts displayed altered cell morphology and impaired ability to contract collagen gel and decreased production of MMP-2. These results provide evidence for an important role for MMP-13 in wound healing by coordinating cellular activities important in the growth and maturation of granulation tissue, including myofibroblast function, inflammation, angiogenesis, and proteolysis.

Modification of Softwood Bleached Pulp Suitable for Viscose Cellulose with High Liquid Water

Softwood pulp was used to prepare dissolving pulp suitable for viscose fiber by three procedures (liquid hot water, sodium hypochlorite oxidation and alkali extraction). The impacts of main factors, such as temperature, reaction time, concentration and chlorine loading on the methylcellulose content and the polymerization degree were investigated. Firstly, the pulp was pretreated by liquid hot water, Under the optimized conditions (concentration 9.0%, temperature 180°C, treating time 40min), the methylcellulose content and the polymerization degree of pulp were 88.47% and 768, respectively. Secondly, the treated pulp was oxidized by sodium hypochlorite. Under the optimized conditions (chlorine loading 2.0%, treating temperature 50°C, treating time 1h), the methylcellulose content and the polymerization degree were 91.54% and 528, respectively. Finally, the oxidized pulp was treated by sodium hydroxide（ alkali loading 13%）under 20°C for 1h. After these procedures, the methylcellulose content and polymerization degree were 95.85% and 536, respectively. The quality of cellulose fiber can meet the utilization requirement for viscose fiber production.

Viscose material functionalized by chitosan as a potential treatment in gynecology

This paper presents the functionalization of viscose cellulose material with chitosan for potential application in cellulose tampons for everyday use that would not display negative side effects, such as irritation of the vaginal wall, toxic shock syndrome, etc. The technological parameters of tampons, amount of amino groups due to chitosan adsorption, and the antimicrobial activity of the tampons were analyzed. Aqueous chitosan solutions buffered with lactic or acetic acid were sprayed on viscose fibers, from which tampons were prepared and dried at 40°C in an air chamber or at room temperature. Adsorption of chitosan was determined by conductometric titration. The absorptivity and antimicrobial activity of the tampons were determined by standard methods. It is concluded that tampons prepared in this way possess the following new properties: maintenance of the physiological pH of the vagina together with its moisturizing effect, good technical properties, and antimycotic, as well as antibacterial, activity.

Understanding and adding value to Eucalyptus fibre

Eucalyptus wood has become one of the most important hardwood resources for pulp mills worldwide. Furthermore, bleached Eucalyptus pulp is used extensively both in paper-making globally where it is included in such diverse products as tissue, packaging, as well as printing papers and in chemical cellulose products such as viscose, acetate and microcrystalline cellulose. This paper investigates and highlights the physical and chemical attributes of the wood and pulp fibre from Eucalyptus that contribute to its popularity in the pulp and paper-making industries and to suggest how these can be enhanced or conserved in the manufacturing process to add maximum value. The fibre properties of macerated wood samples from a range of Eucalyptus species used commercially in South Africa are compared with those of North American hardwoods such as birch, maple and aspen. In comparison to the American hardwoods, the Eucalyptus species were found to have short and thin fibres (on average, fibre length from 0.6 to 0.8 mm and fibre width between 15 and 17 μm, compared with 0.6–1.4 mm and 17–30 μm, respectively, for the American hardwoods. This particular combination of dimensions for the Eucalyptus fibre produces a low fibre coarseness, which is a highly desirable attribute for products such as coated and uncoated papers. The Eucalyptus fibre is therefore reasonably fragile and this makes it particularly vulnerable to damage during the pulp and bleaching processes. Fibre damage occurs throughout the pulp process but is most severe in the mechanical sections such as digester blowing, high shear mixers, medium- and high-consistency pumps as well as low-consistency refining. These areas are highlighted in this paper and possibilities for fibre conservation are discussed.

Electrical capacitance of fibrous carbon composites in supercapacitors

The aim of this work was the application of active carbon composites as electrode material for supercapacitors. We have produced and investigated composites from viscose cellulose fibers impregnated with novolak and resolic resins. Composition and porous structure of the composites were described and electrochemical properties determined by galvanostatic and potentiodynamic methods. Dependence of electrical capacitance on treatment procedure and some of the structural parameters was confirmed. The use of novolak resin for activation with carbon dioxide was more advantageous. Positive electrode revealed better performance in acidic conditions (185 F/g) while negative electrode in alkaline conditions (160 F/g).

The effect of transforming growth factor- β1, released from a bioabsorbable self-reinforced polylactide pin, on a bone defect

Transforming growth factor-beta 1 (TGF- β1)is a polypeptide growth factor which has been shown to increase bone formation in experimental studies. In this study it was combined to a bioabsorbable self-reinforced poly- ld-lactic acid fracture fixation pin. To assess the effect of TGF- β1 on the healing of a bone defect, the pins were implanted in the rat distal femur next to a bone defect filled with a viscose cellulose sponge. The pins used in the study group (13 rats) contained 50 μg of TGF- β1, whereas in the control group of nine rats an identical pin without the growth factor was used. In the histologic examination at 1, 3 and 6 weeks no difference was detected in the amount of bone inside the viscose cellulose sponge between the rats treated with TGF- β1 and those with no added growth factor. At 3 weeks there was more fibroblast-rich mesenchymal tissue inside the viscose cellulose sponge in the rats treated with TGF- β1. In the radiographic examination at 3 weeks there was an increase in the amount of new periosteal bone on the bone defect in the TGF- β1-treated rats.

Sucrose has no beneficial effects on wound healing in rats.

To evaluate the effects of sucrose treatment on the formation of granulation tissue in a standard wound model. Animal study. University hospital, Finland. 32 male Sprague-Dawley rats divided into 4 groups. Implantation of viscose cellulose sponge subcutaneously, and daily injection of three concentrations of sucrose (0.01, 0.1 or 1 M) or vehicle for 7 days. The amount of granulation tissue measured by chemical analysis and histology. The amount and distribution of types I and III collagen assayed by immunofluorescence. None of the three concentrations altered the amounts of DNA, RNA, hydroxyproline, nitrogen, hexosamines, and uronic acids in granulation tissue. Neither improvement nor deterioration was seen in the growth of granulation tissue in histological specimens. The amount and distribution of types I and III collagen was similar in controls and sucrose-treated rats. Type III collagen was most abundant near newly-formed vessels. Neither sucrose nor fructose was found in wound fluid while the concentration of glucose was significantly lower in all test groups than in controls. Sucrose solution had neither beneficial nor deleterious effects on the amount of developing granulation tissue in an experimental wound model. The amount and distribution of types I and III collagens were also not altered by sucrose treatment.

Expression and activity of matrix metalloproteinase‐2 and ‐9 in experimental granulation tissue

The restoration of functional connective tissue is a major goal of the wound healing process which is probably affected by matrix-modifying enzymes. To evaluate the spatial and temporal expression of matrix metalloproteinases (MMP) MMP-2 and MMP-9 and to study the regulation of MMP-2 in wound healing, subcutaneously implanted viscose cellulose sponges in rats were used to induce granulation tissue formation for up to 3 months. MMP-2 mRNA expression was seen throughout the experiment and it was highest after 2 months. MMP-9 gene expression was low between days 8-21 and increased after 4 weeks of granulation tissue formation. Membrane-type 1 MMP (MT1-MMP) mRNA was upregulated early and tissue inhibitor 2 of MMP (TIMP-2) mRNA later during wound healing. In in situ hybridization the expression of MMP-2 mRNA was seen mostly in fibroblast-like cells and MMP-9 mRNA in macrophage-like cells. MMP-9 immunoreactivity was detected in the polymorphonuclear leukocytes and macrophage-like cells on days 3-8. MMP-9 proteolytic activity was observed only on days 3-8. The active form of the MMP-2 increased up to day 14, whereafter it remained at a constant level, whereas latent MMP-2 did not show any apparent changes during the experimental period. We conclude that MMP-2 is important during the prolonged remodelling phase, whereas the gelatinolytic activity of MMP-9 was demonstrated only in early wound healing, and the MMP-9 gene is upregulated when the granulation tissue matures.

Is cellulose sponge degradable or stable as implantation material? An in vivo subcutaneous study in the rat.

The long-term behaviour of cellulose sponge implants, 10 x 10 x 5 mm in size, and tissue reactions in and around them were examined in the subcutaneous tissue of the rat from 1 to 60 weeks after implantation. The cellulose sponge used was filled up with connective tissue 4 to 8 weeks after implantation. Histologically, moderate foreign body tissue reaction inside the implant, the appearance of cracks and fissures, spotty colouration, and softening of the pore walls were observed up to 16 weeks after implantation. Later, the foreign body reaction inside the sponge became milder, the spotty colouration disappeared and micropores enlarged in the viscose cellulose matrix. Histomorphometrically, the cross-sectional area of the implants and the size of the pore wall fragments decreased, and the number of pore wall fragments increased significantly. The cellulose sponge used can be regarded as a slowly degradable implantation material. However, the time needed for the total disappearance of the cellulose sponge from subcutaneous tissue is longer than the 60 weeks.