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To overcome challenges such as pickling, desulphurization, and viscosity reduction experienced during the integration of microcapsules into viscose spinning solutions through the wet spinning process, this study employed the interfacial polymerization method. Polyurea (PUA) and polyurethane (PU) were used as shell materials, with sliced paraffin and wormwood essential oil (WEO) as core materials, to construct double-shell multifunctional microcapsules (DM). These microcapsules were then introduced into a viscose spinning solution. A functional regenerated cellulose fiber was prepared by incorporating sodium alginate and carboxymethyl cellulose as thickeners. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to analyze the chemical component and structure of the DM. The morphology remained intact without damage after the spinning process using viscose wet spinning. Differential scanning calorimetry (DSC), along with an antibacterial experiment and aroma test, revealed that the functional regenerated cellulose fibers exhibited an enthalpy of crystallization and melting of 24.5 J/g and 35.4 J/g, respectively, and manifested a remarkable 100% inhibition rate against Escherichia coli. The microcapsule-based regenerated fibers prepared in this study significantly advance the application of microcapsules in functional viscose wet spinning processes. [ABSTRACT FROM AUTHOR]

The potential for using discarded viscose textiles to produce high-quality viscose fibres is limited by the low molecular weight of the cellulose and its continued reduction in the recycling process. Herein, we present a straightforward approach of reprocessing discarded viscose textiles while achieving high-quality recycled viscose fibres. Discarded viscose textile was defibrated and centrifuged, and the resulting fibres were reprocessed under industrially relevant conditions. The produced viscose dope was fluid and resulted in viscose fibres with properties comparable to fibres made from commercial wood cellulose pulp (titer ~2 dtex; dry elongation ~16%, dry tenacity ~15 cN/tex). To explore the potential for a more environmentally friendly production process, the steeping step was performed twice (double-steeping), thereby producing a more homogeneous viscose dope. Through double-steeping, the consumption of carbon disulfide (CS2) could be reduced by 30.5%. The double-steeping method shows to be a suitable approach to reprocess discarded viscose textiles while reducing the environmental impact of the viscose process associated with the use of CS2. Our work demonstrates that discarded viscose textile has the potential to be part of a circular textile value chain. [ABSTRACT FROM AUTHOR]

As an important branch of hydrogen storage materials, adsorptive materials have unique advantages such as high reversibility, fast adsorption rate and mild release conditions, etc. At present, the research on adsorptive hydrogen storage materials mostly focus on the pressure conditions of 30–300 bar, while the atmospheric hydrogen storage performance of adsorptive materials needs to be further enhanced. Based on the sonication-assisted activation process, micro-nano scale synchronous "carving" of viscose fiber was achieved in activation process for viscose fiber after carbonization, and petaloid activated carbon fibers (FL-VACFs) and rod-shaped activated carbon fibers (RL-VACFs) were constructed. Specific surface area of FL-VACFs and RL-VACFs can reach 1085.77 m2 g−1 and 956.81 m2 g−1 respectively, and the ultramicropore relative contents can reach 44% and 52.08% respectively. Under the synergistic action of abundant ultramicropores and oxygen-containing functional groups, FL-VACFs and RL-VACFs exhibit excellent hydrogen storage density of 2.04 wt% at77 K, 1 bar. Additionally, Multisite-Langmuir model (N = 3) model is discovered more suitable for accurate describing the hydrogen adsorption process of FL-VACFs and RL-VACFs under atmospheric pressure. [Display omitted] • Micro-nano scale synchronous "carving" of viscose fiber surface was achieved by sonication-assisted activation process. • Petaloid and rod-shaped activated carbon fibers are constructed with high specific surface area. • It exhibit excellent hydrogen storage density of 2.04 wt% under atmospheric pressure. [ABSTRACT FROM AUTHOR]

The global textile fiber output increased five times from 1975 to 2020. Also, in 2010, the combined demand for man-made and natural fibers was projected to increase by 84% within 20 years. Clothing materials are largely made from cotton or petroleum-based synthetic fibers; both sources, however, have adverse environmental impacts. Thus, cotton requires vast amounts of land, water, fertilizers and pesticides, and synthetic fibers are not biodegradable. This scenario has raised the need for further exploration of cellulose polymers as sustainable sources for the textile industry. Cellulose, the most abundant renewable organic material on earth, is an outstanding polymer that by chemical derivatization or modification can offer a broad range of applications. Dissolving-grade pulp (DGP), which consists of highly pure cellulose, is the most suitable material for manufacturing cellulose derivatives and regenerated fibers. The latter are typically obtained by using the viscose process, which has considerable adverse environmental impacts. Although the textile industry has progressed substantially, further efforts are still needed to make its entire production chain more sustainable. This article provides an in-depth introduction to the potential of fibers with a high cellulose content, known as dissolving-grade pulps. It reviews the properties of DGP, the cooking and purifying methods typically used to obtain it, and the process by which paper-grade pulp can be converted into dissolving-grade pulp. Also, it discusses traditional and recently developed technologies for producing regenerated cellulose fibers. Finally, it examines the potential for recovering cellulose from textile waste as a novel sustainable practice. [ABSTRACT FROM AUTHOR]

Eco-unfriendliness of viscose process − the main producer of tire cord from wood cellulose − does not meet the growing need for creation of "green" tires. Alongside viscose cord fiber, production of a new cord fiber, Lyocell, from wood cellulose by eco-clean NMMO process is developing. Technical fibers were obtained from high-molecular flax cellulose by the method of its solid-phase dissolution in N-methylmorpholine-N-oxide. Comparative studies of the structure and mechanical and thermal properties of flax fibers and industrial cord fibers showed correspondence of their properties and that the stiffness of the flax fiber is almost 30 % higher than that of the cord fiber. Flax fibers are resistant to cyclic deformative actions and their deformation at high temperature is less than that of commercial samples. Water losses by the samples in the process of thermal studies at temperatures up to 170 °C have a reverse nature, which is confirmed by the stability of the mechanical properties of the samples under equilibrium conditions after thermal action. The obtained data set indicates sufficiently high fatigue strength of flax fibers and makes it possible to use them as cord fiber at par with cord fiber from wood cellulose. [ABSTRACT FROM AUTHOR]

(1) Background: It is simpler and more environmentally friendly to use supercritical CO2 fluid technology to process skincare viscose fabrics. Therefore, it is significant to study the release properties of drug-loaded viscose fabrics to choose suitable skincare drugs. In this work, the release kinetics model fittings were investigated in order to clarify the release mechanism and provide a theoretical basis for processing skincare viscose fabrics with supercritical CO2 fluid. (2) Methods: Nine kinds of drugs with different substituent groups, different molecular weights, and different substitution positions were loaded onto viscose fabrics using supercritical CO2 fluid. Then, the drug-loaded viscose fabrics were placed in an ethanol medium, and the release curves were drawn. Finally, the release kinetics were fitted using zero-order release kinetics, the first-order kinetics model, the Higuchi model, and the Korsmeyer–Peppas model. (3) Results: The Korsmeyer–Peppas model was the best-fitting model for all the drugs. Drugs with different substituent groups were released via a non-Fickian diffusion mechanism. On the contrary, other drugs were released via a Fickian diffusion mechanism. (4) Conclusions: In view of the release kinetics, it was found that the viscose fabric can swell when a drug with a higher solubility parameter is loaded onto it using supercritical CO2 fluid, and the release rate is also slower. [ABSTRACT FROM AUTHOR]

Circularity of cellulose-based pre- and post-consumer wastes requires an integrated approach which has to consider the characteristics of the fibre polymer and the presence of dyes and additives from textile chemical processing as well. Fibre-to-fibre recycling is a condition to avoid downcycling of recycled material. For cellulose fibres regeneration via production of regenerated cellulose fibres is the most promising approach. Textile wastes contain dyes and additives, thus a recycling technique has to be robust enough to process such material. In an ideal case the reuse of colorants can be achieved as well. At present nearly 80% of the regenerated cellulose fibre production utilises the viscose process, therefore this technique was chosen to investigate the recycling of dyed material including the reuse of the colorant. In this work, for the first time, a compilation of all required process steps to a complete circular concept is presented and discussed as a model. Indigo-dyed viscose fibres were used as a model to study cellulose recycling via production of regenerated cellulose fibres to avoid downcycling. Indigo was found compatible to the alkalisation and xanthogenation steps in the viscose process and blue coloured cellulose regenerates were recovered from indigo-dyed cellulose. A supplemental addition of reduced indigo to the cellulose solution was also found feasible to adjust colour depth in the regenerated cellulose to the level required for use as warp material in denim production. By combination of fibre recycling and indigo dyeing the conventional yarn dyeing in denim production can be omitted. Model calculations for the savings in water and chemical consumption demonstrate the potential of the process. The proportion of the substitution will depend on the collection rate of denim wastes and on the efficiency of the fibre regeneration process. Estimates indicate that a substitution of more than 70% of the cotton fibres by regenerated cellulose fibres could be achieved when 80% of the pre- and post-consumer denim wastes are collected. Therefore, the introduction of fibre recycling via regenerated cellulose fibres will also make a substantial impact on the cotton consumption for jeans production. [ABSTRACT FROM AUTHOR]

Cellulose dissolution in the viscose process has been facilitated through derivatization by carbon disulphide (CS2) at xanthation stage by converting alkali cellulose (AC) to cellulose xanthate (CX). CX formation has been always accompanied with sulphur based byproducts formation as dictated by the mechanism published in earlier study (Gondhalekar et al. (Cellulose 26 3 1595–1604, 2019)). The sulphur byproducts formed during viscose synthesis are sodium sulphide (Na2S), sodium trithiocarbonate (Na2CS3: TTC) and other minor sulphur compounds. These byproducts continue to form during ripening process as dictated by time and temperature coupled with concentration of free caustic and CS2 present in the system. These byproducts get converted into sodium sulphate (Na2SO4), hydrogen sulphide (H2S), CS2 and other sulphurous compounds during spinning. Overall, uncontrolled ripening without parametric optimization adversely impacts raw material (RM) consumption and creates sustainability challenges. Overall optimization based on viscose process fundamental insights presented in this study will effectively help in achieving operational excellence by reducing rate of undesired reactions to improve RM specific consumption and will compliment overall sustainability efforts in viscose industry. [ABSTRACT FROM AUTHOR]

Textile filaments were fabricated from a solution obtained from carboxymethylated cellulose dissolved in aqueous NaOH solution, by wet spinning in an acid coagulation bath. Spinning is possible for modified cellulose with a carboxyl group content of at least 1.3 mmol/g cellulose. A post-treatment—heating in the presence of sodium hypophosphite—improved the properties of these filaments. This is a novel process, much more environmentally friendly than the viscose process for the production of rayon, in which most of the chemicals can be reused making it likely that the process is economically viable. After extrusion in an acid bath, filaments containing 1.3 mmol –COOH/g cellulose could be washed with water quite readily, a process very difficult for filaments with carboxyl group content of 1.5–1.7 mmol/g cellulose. The tenacity of the filaments obtained from the modified cellulose with a carboxyl group content of 1.3 mmol/g cellulose was 1.0 cN/dtex, which was higher than that of the filaments with carboxyl group contents of 1.5 mmol/g cellulose (tenacity 0.93 cN/dtex) and 1.7 mmol/g cellulose (tenacity 0.88 cN/dtex). The water absorbency of the filaments made from the modified cellulose with carboxyl group content of 1.3 mmol/g cellulose was 0.54 g water/g filaments which was ~ 2 times and ~ 3.5 times lower than that of the filaments with carboxyl group contents of 1.5 mmol/g cellulose and 1.7 mmol/g cellulose, respectively. The values of tenacity and water absorbency for filaments with 1.3 mmol/g cellulose are extremely promising for textile applications. [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant renewable resource which has found a diverse range of applications. Cellulose dissolution is a significant property for manufacturing man-made cellulosic fiber through viscose process. Crystalline microfibrillar structure and relatively high ordered packing of polymeric chains contribute to recalcitrance and poor reactivity of cellulose. One of the most common methods to improve cellulose dissolution is cellulase treatment. Herein, cellulase treatment at different doses was studied to explore the correlation of cellulose dissolution with crystallinity. Pulp showed improvement in Fock reactivity and other properties related to viscose application. But contrary to previous studies, cellulose crystallinity as determined by XRD and FTIR did not correlate with Fock reactivity at a higher dose of cellulase. The results indicated some complex mechanism to be involved between the cellulose dissolution and crystallinity than a simple negative correlation. Cellulase treatment at 150 HCU/g resulted in the upgraded pulp suitable for viscose application. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to analyze the environmental impact of the viscose fiber/lyocell fiber manufacturing industry and obtain improvement information from China's analysis results. Our main research question is: How will the production of viscose/lyocell fiber affect the environment? Which raw material or process has the most significant impact on the environment? Is it possible for lyocell fiber to replace viscose fiber that has a greater impact on the environment? Methods: For the life cycle assessment (LCA) method, we use the analysis from the raw materials (pulp) to the end of the production (fiber) process. The paper mainly introduces the water consumption, energy utilization, and the production of three industrial wastes in producing the two fibers. The life cycle inventory input and output data were collected from two fiber manufacturers in China (manufacturing viscose fiber and lyocell fiber, respectively). Six impact categories were calculated using eFootprint online platform, including primary energy consumption (PED), non-living resource consumption potential (ADP), Resource depletion–water (WU), global warming potential (GWP), acidification potential (AP), and ecotoxicity (ET). Results and discussion: There is no significant difference between the ADP and WU values of the two processes from a comprehensive comparison. In PED, the value of lyocell fiber is approximately three times that of viscose fiber. Because viscose fiber uses more sulfide; its AP value is about twice that of lyocell fiber. The GWP of lyocell fiber is about two of that of viscose fiber. The ET value of viscose fiber is an order of magnitude higher than that of lyocell fiber. In the viscose fiber process, steam, pulp, ZnSO4, and sulfuric acid are the main contributors to the process's environmental impact. The main contribution rates of steam to PED, WU, GWP, and AP are 23.6%, 16.76%, 43.33%, and 18.99%, respectively. The use of ZnSO4 in viscose fiber resulted in an ET value of more than 90%. Alternatives can be found to reduce the environmental impact further. It is of great significance to study materials that can replace ZnSO4 as additives. In the lyocell fiber process, electricity, pulp, and steam are the main contributors to the process. The main contribution rates of electricity to PED, ADP, GWP, AP, and ET are 57.5%, 62%, 51%, 59.9%, and 69.3%, respectively. At present, this process mainly uses thermal power generation, which makes the environmental impact caused by electricity consumption great. If more economical or cleaner power supply can be considered, the environmental impact will be further improved. [ABSTRACT FROM AUTHOR]

A CO2 switchable solvent system is investigated to find an environmentally friendlier way to produce man‐made cellulose fibers. Cellulose solutions with concentrations from 2 wt% to 8 wt%, based on derivative and non‐derivative dissolution approaches, are investigated. Three different switchable solvent systems are tested. After accessing the stability of the produced cellulose solutions, their regeneration is investigated using different alcoholic coagulation media. In order to find a suitable coagulation medium and stable cellulose solution, a dissolution–regeneration cycle is investigated, while trying to minimize the amount of waste by recovering the employed solvents. The process is optimized and the resulting fibers are characterized by infrared (IR) spectroscopy, optical microscopy, as well as scanning electron microscopy. [ABSTRACT FROM AUTHOR]

We describe the wet and dry‐wet spinning of multifilament cellulosic composite fibers, namely chitin/cellulose fibers. The direct solution process for the two biopolymers based on an ionic liquid as solvent represents an environmentally friendly and alternative technology to the industrially applied viscose and lyocell process. Both cellulose and chitin possess good solubility in 1‐ethyl‐3‐methylimidazolium propionate ([C2C1Im][OPr]) and were spun into multifilament composite fibers. Moreover, for the first time, pure chitin multifilament fibers were obtained by dry‐wet spinning. The effect of chitin addition on the filament properties was investigated and evaluated by microscopic, spectroscopic, and mechanical analyses. [ABSTRACT FROM AUTHOR]

Lyocell fibers have received increased attention during the recent years. This is due to their high potential to satisfy the rising market demand for cellulose-based textiles in a sustainable way. Typically, this technology adopts a dry-jet wet spinning process, which offers regenerated cellulose fibers of excellent mechanical properties. Compared to the widely exploited viscose process, the lyocell technology fosters an eco-friendly process employing green direct solvents that can be fully recovered with low environmental impact. N-methylmorpholine N-oxide (NMMO) is a widely known direct solvent that has proven its success in commercializing the lyocell process. Its regenerated cellulose fibers exhibit higher tenacities and chain orientation compared to viscose fibers. Recently, protic superbase-based ionic liquids (ILs) have also been found to be suitable solvents for lyocell-type fiber spinning. Similar to NMMO, fibers of high mechanical properties can be spun from the cellulose-IL solutions at lower spinning temperatures. In this article, we study the different aspects of producing regenerated cellulose fibers using NMMO and relevant superbase-based ILs. The selected ILs are 1,5-diazabicyclo[4.3.0]non-5-ene-1-ium acetate ([DBNH]OAc), 7-methyl-1,5,7-triazabicyclo[4.4.0] dec-5-enium acetate ([mTBDH]OAc) and 1,8-diazabicyclo[5.4.0]undec-7-enium acetate ([DBUH]OAc). All ILs were used to dissolve a 13 wt% (PHK) cellulose pulp. The study covers the fiber spinning process, including the rheological characterization of the various cellulose solutions. Moreover, we discuss the properties of the produced fibers such as mechanical performance, macromolecular properties and morphology. [ABSTRACT FROM AUTHOR]

Alkali extraction of cellulose material is a common treatment for several industrial processes—especially the viscose process, which produces fibers for textile applications. This study investigated different generic dissolving wood pulps by means of alkali extraction (10–18 wt% aq. NaOH at 20–50 °C). The regenerated residue of the pulps was characterized for its chemical composition, molecular structure, and cellulose conformation. The investigated pulps had in common that glucan was most intensely extracted at low temperature and low concentration of aqueous alkali, xylan was most intensely extracted at high temperature and high concentration of aqueous alkali, and mannan was most intensely extracted at a concentration of aqueous alkali > 14 wtwt% at all temperatures applied. The degree of transformation via alkali cellulose to cellulose II as determined with Raman spectroscopy was found to be maximized for all pulps at high alkali concentration and temperature had no major influence. Maximum yield for all investigated pulps was found when extraction was done with 18 wt% aq. NaOH. The importance of temperature differed for the investigated pulps. The reason for the differences in extraction behavior or different absolute levels of resulting properties was found to be related to differences in the homogeneity and purity of the pulps. A conclusion of interest for industrial applications was that extracting the pulps with 18 wt% aq. NaOH led to an optimal alkalization result for yield, purity, and conversion. The steeping temperature chosen was found to be important to balance the yield and the purity of xylan-containing pulps. [ABSTRACT FROM AUTHOR]

Regenerated cellulose fibers manufactured using Lyocell and Viscose processes exhibit differences in their structural response to mechanical deformation. Here, we study the effect of stretching and stress relaxation on the orientation of crystal and amorphous phases. Our results show that on stretching, orientation in both crystal and amorphous phases increases linearly with strain, correlating with the increase in stress and with the stretching of the crystalline unit cell along the c-axis. On holding after stretching to a particular strain, the stress relaxes logarithmically in time, correlating with a decrease in the strain along the c-axis of the crystal unit cell. The stress relaxation is also correlated with a logarithmic increase in amorphous orientation, while crystalline orientation stays constant. We attribute the stress development during stretching to deformation of the crystal unit cell, while crystal reorientation in the fiber direction results in increase in the crystalline orientation parameter. On holding the fiber at a fixed total strain, the stress relaxes as strain is transferred from crystal to amorphous regions. Thus, the strain on the unit cell c-axis decreases and amorphous orientation increases. There are quantitative differences between the rate of increase in amorphous phase orientation during stress relaxation for Lyocell and Viscose fibers. For dry fibers, Lyocell shows a slower increase in orientation during stress relaxation. On wetting the fibers, their structural response changes qualitatively. We combine wide angle x ray diffraction and birefringence experiments with our model to infer that that on stretching the wet fiber, the crystalline phase is neither strained nor oriented. However, orientation develops in the amorphous phase. During stress relaxation in wet condition, Lyocell fibers shows a faster increase in amorphous orientation than Viscose fibers, in line with the comparison of relaxation time spectra for wet Viscose and Lyocell fibers. [ABSTRACT FROM AUTHOR]

Recent years have witnessed an increasing interest in man-made cellulosic fibers, whose production generally requires cellulose dissolution and regeneration. Cellulosic fibers are difficult to dissolve. Thus, the recalcitrance of wood pulp can be an estimate of its reactivity. Pulp reactivity is usually assessed via complex and time-consuming laboratory simulations of the viscose process. This study proposes a faster and more convenient approach. The dissolution-based torque reactivity (DTR) test measures the evolution of the rheological properties of a pulp suspension under dissolution in cupriethylenediamine. Reactivity is quantified in terms of initial dissolution rates (IDR) and dissolution times (DT). This study describes the measurement protocol for the DTR test and its application to some commercial pulps and a series of pulps hornified to different extents. The IDR and DT values were compared with other pulp features, including degree of polymerization, molecular weight distribution, specific surface area and water retention value. The DTR test proved to be reasonably precise and fast to carry out. [ABSTRACT FROM AUTHOR]

Enhancing the fire-retardant and antibacterial properties of viscose fabric through a simple strategy is crucial and urgent. In this study, an aminoazole-based cyclotriphosphazene (HATA) was designed and synthesized through nucleophilic substitution between hexachlorocyclotriphosphazene and 3-amino-1,2,4-triazole. The application of a rapid dipping strategy and the use of 10 wt% HATA aqueous solution significantly increased the limiting oxygen index of the viscose fabric from 19.3 % to 28.4 %. In addition, the HATA-treated fabric exhibited self-extinguishing properties in vertical flame testing. The peak heat release rate of HATA-treated fabric, according to pyrolysis combustion flow calorimetry, significantly decreased by over 83 %. The scanning electron microscope images revealed the original woven fabric structure after burning. The thermogravimetric infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed that the introduction HATA in viscose hindered the release of combustible gas and facilitated the formation of a protective char layer. In addition, 10 % HATA-viscose exhibited remarkable antimicrobial properties, achieving 99.96 % and 99.84 % antibacterial rates against Staphylococcus aureus and Escherichia coli , respectively. Furthermore, HATA-treated viscose fabric exhibited favorable mechanical performance, whiteness, and air permeability. This research provides a simple and effective flame-retardant and antibacterial treatment strategy for viscose fabric. • Aminoazole-based cyclotriphosphazene was synthesized as a high-efficiency flame-retardant antibacterial agent. • An eco-friendly and expeditious immersing process endows viscose with notable flame retardancy and antibacterial efficacy. • The finishing process remains the tensile strength and breathability of viscose. [ABSTRACT FROM AUTHOR]

The cellulose reactivity is a critical parameter in the manufacturing process of viscose rayon with dissolving pulp. In this study, an ultrasonic treatment, which is considered as an environmentally friendly pretreatment technology, was applied to a softwood prehydrolysis kraft-based dissolving pulp for enhancement of accessibility/reactivity in terms of viscose rayon production through cavitation of ultrasound. Results show that the ultrasonic treatment can lead to the decrease of cellulose crystallinity, the increase of specific surface area and average pore diameter in fibers, and the increase of water retention value due to the release of energy induced by the collapse of the gas/vapor bubbles. As a consequence, the Fock reactivity and viscose filterability of dissolving pulp is enhanced significantly after ultrasonic treatment. Other parameters, such as intrinsic viscosity and fiber morphology were also determined. [ABSTRACT FROM AUTHOR]

Viscose staple fibres are produced by multi-stage chemical intensive unit operations. Low pulp reactivity is the main reason for higher consumption of chemicals, especially CS2 and NaOH. Electron beam irradiation (EBI) is one potential way to reduce chemical consumption by improving the pulp reactivity. In the present study, pulp reactivity improves from 28.73 to 33.87 and 39.85 for pulp irradiated at 2 kGy and 5 kGy, respectively, as compared to non-irradiated pulp. The viscose dope prepared from the irradiated pulp shows improvement in filterability (kw) and ripening index. This indicates improved mass transfer through EBI treatment by providing pulp accessibility towards NaOH and CS2. [ABSTRACT FROM AUTHOR]

Abstract The goal of this study was to assess the environmental impact of cellulose carbamate fiber production, using discarded cotton textiles as raw material, and compare the results to reference cotton and viscose fibers. Life cycle inventory and assessment was conducted for two production process scenarios within a cradle-to-gate system. Carbon footprint, water use, and water scarcity footprint were assessed. The results show that the carbon footprint of a cellulose carbamate factory integrated with a pulp mill, and that recycles water and chemicals in energy-intensive operations, is comparable to viscose production in Europe. Cellulose carbamate fiber production consumes less than 2% and 25% of the water consumed by cotton and viscose fiber production, respectively. For a factory located in Äänekoski in Finland, the water scarcity footprint was 15 m3 water eq. per 1000 kg carbamate fiber. For Augsburg, Germany, a likely alternative location, the water scarcity footprint was 18 m3 water eq. per 1000 kg carbamate fiber. Carbon footprint and local impact of water use give information that can be utilized to determine optimal locations for a carbamate factory. The study also indicated that discarded cotton textiles can be used as a cellulosic feedstock without increasing the carbon footprint and water use compared to the commercial viscose process. Additionally, by using cellulose carbamate technology, occupational health risks and the environmental burden of carbon disulfide and hydrogen sulfide emissions from viscose process vents can be avoided. Graphical abstract Image 10201538 Highlights • Carbon footprint of carbamate fibers is close to viscose produced in a modern mill. • Fiber spinning has the largest contribution to the carbon footprint. • Circulation of chemicals and water reduces the carbon footprint. • Water use of cellulose carbamate fiber production is 2% compared to cotton. • Use of discarded textiles as raw material lowers the use of natural resources. [ABSTRACT FROM AUTHOR]

Regenerated cellulose fibers are produced using two industrially dominant technologies: the viscose and lyocell processes. Here, we compare commercially available fibers, prepared using the viscose and lyocell processes. Single fibers are subjected to a variety of mechanical deformations to obtain stress–strain, stress relaxation and stress recovery data. These are fitted to a phenomenological model, whose parameters are interpreted in terms of the fiber semicrystalline microstructure. This simple model does not incorporate the complexities of semicrystalline microstructure. Rather, it represents structure in a semicrystalline polymer fiber in terms of an elastic crystalline phase that coexists with a viscoelastic Voigt-like glassy amorphous phase. Lyocell fibers are characterized by higher values of crystalline modulus relative to viscose. Lyocell fibers also have a higher amorphous phase modulus and a wider relaxation spectrum than viscose, suggesting that amorphous and crystalline phases are dispersed in close connectivity in lyocell. Viscose and lyocell fibers exhibit qualitative similarities in their mechanical response. On stretching, there is a transition in the stress–strain curve from a low strain elastic response at a critical value of strain. This critical strain has been incorrectly attributed to yielding of the fiber. We establish that this critical value corresponds to an apparent yield. When subjected to strains higher than this apparent yield point, the fibers develop a memory of the mechanical deformation. This memory decays slowly, logarithmically with time and is lost over about a day as the fiber structure transitions back to the original as spun fiber. Finally, we demonstrate that on wetting the fibers with water, there is an increase in the apparent yield strain for viscose fibers, but not for lyocell. We interpret these results in terms of the semicrystalline microstructure of the fibers. [ABSTRACT FROM AUTHOR]

Abstract: Xanthation reaction in viscose process is heterogeneous reaction (gaseous CS2-wet alkaline cellulose) complicated with side reactions. Commercial requirement of CS2 in viscose process is 32-34%, which is significantly higher than the stoichiometric requirement (23.5% w/w of the cellulose) due to formation of byproducts. Detailed xanthation reaction kinetics study was performed to understand the xanthate and by-products formation mechanism along with effect of mass transfer and its possible impact on CS2 consumption. Heterogeneous nature of the xanthation reaction offers significant mass transfer resistance and was hypothesized to be driven by CS2 partitioning into wet alkali cellulose and its unstable complex (DTC—dithiocarbonate) formation with alkali. Xanthation reaction mechanism in the form of physico-chemical process steps has been proposed with experimental justification.Graphical abstract: [ABSTRACT FROM AUTHOR]

Changes in the molecular-weight distributions of low-molecular-weight and alkali cellulose after the processes of γ-irradiation and mercerization of cellulose have been studied. The features of the dissolution of irradiated cellulose in an alkaline solution during mercerization have been revealed. It has found that the alkali cellulose produced from the irradiated polymer has increased homogeneity of the molecular-weight distribution. The γ-irradiation of cellulose before mercerization leads to an increase in the reactivity of the polymer in the xanthogenation reaction by 30–50%. An optimum range of absorbed doses for the radiation pretreatment of cellulose prior to a viscose production process has been determined. [ABSTRACT FROM AUTHOR]

The highest single fiber tenacity obtained from the proof-of-concept trials exceeded 2 cN/dtex, however variation in properties from fiber to fiber was large and thus, the average values were moderate. The water absorption capacity of Biocelsol fibers is superior compared to cotton, viscose and lyocel fibers. This is most probably due to high porosity of the Biocelsol fiber structure [9] which is also suggested to be responsible for more efficient dyeing ability of the Biocelsol fibers compared to cotton and viscose fibers [10]. [Extracted from the article]

Many previous studies have found that transabdominal ultrasound may allow precise measurement of gastric emptying of liquid meals. However, the clinical use of this technique has been hampered by the limitation that transabdominal ultrasound might not accurately measure gastric emptying of solid meals. It is more important to measure gastric emptying of solids instead of liquids, as gastric emptying of solids is more often delayed than gastric emptying of liquids in gastric motility disorders. Recently, transabdominal ultrasound after oral administration of a cellulose-based gastric contrast agents (TUS-OSCA) has been suggested to be effective in initial screening of gastric lesions. The aim of this study was to explore the accuracy of TUS-OSCA in the evaluation of gastric emptying of a semisolid meal. Twenty healthy young patients (10 males and 10 females aged 25.5 ± 2.5 y) were studied. Concurrent measurements of gastric emptying by scintigraphy and TUS-OSCA were performed after ingestion of 350 mL semisolid ultrasound agent labeled with 20 MBq 99mTc-sulfur colloid. There was no significant difference in the overall curves for gastric emptying time between scintigraphy and TUS-OSCA. There was a good correlation between the gastric 50% emptying times determined by scintigraphy (89.4 ± 1.8 min) and TUS-OSCA (92.5 ± 1.7 min). The correlation coefficient was r = 0.922 (p = 0.000). Current results indicate that TUS-OSCA is accurate, and the results are similar to those obtained by scintigraphy for gastric emptying of a semisolid meal. [ABSTRACT FROM AUTHOR]

Nanoclays are among the more important industrial minerals. They are inexpensive, widely available in nature, and environment friendly. Nano kaolin (NK) is used to impart additional values of viscose fabrics. The mentioned fabrics were treated with different concentrations of NK using pad-dry cure technique. The surface morphology and surface chemical elements of treated as well as untreated fabrics were investigated using scanning electron microscopy and dispersive X-ray spectroscopy, respectively. Tensile strength and elongation, thickness, bending length, moisture regain and antimicrobial activity of the treated fabrics were evaluated. New colouring material (Thiazolidin), direct and reactive dyes were used for dyeing the treated and untreated fabrics. K/S and washing fastness of the dyed fabrics were assessed and statistically compared using t test. The effect of treatment and dying on performance properties of garments were evaluated by calculating quality factor for each fabric. [ABSTRACT FROM AUTHOR]

In this work, the pilling behaviour of polyester blended fabrics was studied and analysed statistically. Two different groups of blends were selected, namely polyester/cotton (P/C) and polyester/viscose blends (P/V). All the fabrics were assessed for pilling performance using ICI pill box, and two-way ANOVA was conducted to analyse the effect of the number of revolutions and type of fibres on the pilling behaviour of the fabrics. The analysis was further narrowed down by conducting a series of ANOVA, by segregating the number of revolutions into two stages and blend proportions into three stages for group I fabrics. Similarly for group II fabrics, both the, number of revolutions and blend proportions were segregated into two stages each. It was found that the type of component fibre used to produce the fabric loses its significance as the number of revolutions increases. [ABSTRACT FROM AUTHOR]

The flame retardancy of flame retardant viscose (FRV) fiber can be significantly further improved by simple blending with alginate (A) fiber, even though with the content of 10 wt%. Cone calorimeter results showed that longer time to ignition (TTI), lower peak heat release rate (PHRR) and total heat release (THR) can be achieved in FRV after mixing with A. For example, the TTI of FRV can be raised from 10 s to 41 s after blended with only 10 wt% A. The mechanism of the effective suppression of flammability mentioned above was put forward by thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) and pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS). It was found that the content of released CO 2 for FRV/A was higher than that of pure FRV, and the content of the flammable gases for FRV/A, such as hydrocarbons, aldehydes, ethers and alcohols, was lower than that of FRV. In this way, the flame retardancy of FRV was effectively enhanced after blending with A. [ABSTRACT FROM AUTHOR]

In this work, using cotton pulps and urea as raw materials, cellulose carbamates (CCs) were successfully prepared by liquid-solid phase in the high-boiling aprotic and polar solvent (DMAc). Regenerated cellulose (RC) fibers were successfully spun from cellulose carbamate in a NaOH aqueous solution by wet spinning on a conventional viscose filament device. And the structures and properties of products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), Thermal gravimetric analysis (TG) and Scanning electron microscopy (SEM), rheology measurement and dye testing. The results showed that the CC can be quickly dissolved in 9%NaOH solution. RC fibers exhibited a bright surface and an approximately circular cross section. There was no lobulate shape and contained obvious pores and voids in the internal sections. RC fibers demonstrated a typical cellulose II crystal structure and a good thermal stability. And tensile strength of the RC fibers was 1.4 cN/dtex, and their elongation at break was 6.8%. Furthermore, the RC fibers showed excellent dyeing properties compared with viscose rayon and Yingli Lyocell. So, the described carbamate pathway provided a simple and environmentally friendly method to overcome the environmental drawbacks of the traditional viscose process. [ABSTRACT FROM AUTHOR]

We report a novel manufacturing method for bio renewable regenerated cellulose fibres modified with curcumin, a molecule is known for its medicinal properties. Ionic liquid namely 1-Ethyl 3-Methyl Imidazolium diethyl phosphate (emim DEP) was found to be capable of dissolving cellulose as well as curcumin. Regenerated cellulose/curcumin composites fibres with curcumin concentration ranging from 1 to 10 wt% were manufactured using dry jet wet fibres spinning process using three different winding speeds. All the cellulose and curcumin composite fibres showed distinct yellow colour imparted by curcumin. The resultant fibres were characterised using scanning electron microscopy (SEM), infrared spectroscopy, mechanical testing, and X-Ray diffraction studies. Scanning electron microscopy of cellulose/curcumin fibres cross-section did not show curcumin aggregates in cellulose fibres indicating uniform dispersion of curcumin in cellulose matrix. The cellulose chain alignment in cellulose/curcumin composite fibres resulted in tensile strength ranging from 223 to 336 MPa and Young’s modulus ranging from 13 to 14.9 GPa. The mechanical properties of cellulose/curcumin composite fibres thus obtained are better than some of the commercially available regenerated cellulose viscose fibres. The wide-angle X-ray diffraction analysis of cellulose/curcumin composite fibres showed good alignment of cellulose chains along the fibre axis. Thus, our findings are a major step in manufacturing strong cellulose fibres with a pharmacologically potent drug curcumin which in future could be used for medicinal, cosmetic and food packaging applications. [ABSTRACT FROM AUTHOR]

Silver containing activated carbon fiber (Ag/ACF) has excellent adsorption properties for removing dyes. Silver particles are loaded onto ACF after carbonization and activation at present, and the fibers have low washing resistance and impurities are introduced onto ACF. In this research, pre-treatment techniques were used. Nano-silver solution with a particle size about 10 nm was prepared by using β-cyclodextrin as a stabilizer and reducer, and then the nano-silver solution was used as pretreatment liquid for modifying viscose fiber. Nano-silver particles with functional groups have high activity and can be readily adsorbed on the surface of viscose fibers. Ag/ACF was successfully prepared by carbonizing and activating the Ag-containing viscose fiber. The number and content of nano-silver particles on the surface of ACF was controlled by changing the concentration of nano-silver solution. The results show that the Ag/ACF have a high washing resistance and more efficiently remove methyl orange (MO) and methylene blue (MB) than ACF. [ABSTRACT FROM AUTHOR]

Functional finishing of viscose knitted fabrics was realized through layer-by-layer assembly with graphene oxide and reduction treatment of hydrazine hydrate. Due to the introduction of graphene, viscose fabrics became conductive, and exhibited enhanced anti-ultraviolet properties and hydrophobicity. Scanning electron microscopy results demonstrated that graphene could form thin films on the surface of viscose fibers, and with an increase in dipping-drying cycles, partial peeling of the thin films was observed. Electrical resistivity tests indicated that the volume resistance could reach to 128 Ω·cm and 96 Ω·cm when the courses and wales of the viscose fabrics treated for thirty dipping-drying cycles. In addition, ultraviolet protection factor of the viscose fabrics was 100+ and the water contact angle of the viscose fabrics treated for twelve cycles was 125° compared with 18° for the original fabrics. These multifunctional fabrics have potential applications in conductive devices, water treatment systems and smart textiles. [ABSTRACT FROM AUTHOR]

The focus of the work was to clarify the influence of the cross section shape of the viscose fibers and additives on the carbonization process and the resulting carbon fiber properties. Overall, the shape of cross section of carbon fibers produced was determined by the initial fiber morphology of the precursor viscose fibers. The carbon yield was independent of the geometric structure of the viscose fibers and a certain degree of shrinkage was observed for all types of fibers due to the loss of water, hydrocarbons and other volatile products. Several additives, such as carbon black, a nitrogen containing carbohydrate and lignin, were homogenously incorporated into the precursor fiber and resulted in slight increase of the carbon yield. Carbon black particles became distinctive and visible on the surface of the carbon fibers. In particular, the thermal and chemical course of the carbonization was altered by the nitrogen containing additive, while the structure and properties of the carbonized fibers remained basically unchanged. [ABSTRACT FROM AUTHOR]

A type of antibacterial bacterial cellulose (BC) film was prepared for potential uses as wound dressing. In order to obtain a high antibacterial effect, some forms of BC films, including the wet and dried ones were utilized as the template to in situ synthesize silver nanoparticles (AgNPs). The effects of drying methods including freeze-drying, heat drying and air drying, on the microstructures and physical properties of BC, as well as the silver contents and the antibacterial performances of the BC/AgNPs composites were investigated. It was found that the AgNPs impregnated on the dried BC films were inclined to achieve a faster silver releasing rate than the wet one, which was suitable for acute traumas treatment. [ABSTRACT FROM AUTHOR]

The optimum surface and frictional properties of textiles depend on their specific application. In this study, we examined the frictional behaviour of medical wipes against 15 mechanical near skin equivalents using synthetic leather material and bovine leather. The frictional behaviour characteristics, both static and kinetic, were evaluated at four different normal loads. It was seen that the static and kinetic frictional coefficients decrease with an increasing normal load for all the reference candidates studied. Higher friction was experienced for the movement of the cotton and viscose wipe against leather than that for synthetic polyurethane (PU) and silicone material.The friction of the wipe against any equivalent skin material was found to be dependent on its surface nature and the morphology of the material against which it is in contact and moves. Friction is necessary in real-time use for a wipe to have an inherent frictional resistance for movement against skin during use. [ABSTRACT FROM AUTHOR]

The main aim of this work is to investigate gas–oil relative permeability curves as the main flow function in different gas injection scenarios, immiscible and near miscible in case of highly fractured reservoirs. In this research, some experiments have been done on the reservoir core sample selected from sandstone formation in one of the Iranian naturally fractured oil reservoirs. The core is saturated with oil sample and CO 2 is injected into oil saturated core sample. Experiments have been performed on both of the sandstone and artificial fractured sandstone, represented as no fractured and highly fractured reservoirs, based on incremental pressure algorithm approaching into near miscible condition. Inverse modeling method has been used to calculate relative permeability curves. By comparing the relative permeability curves in immiscible and near-miscible conditions, the results show that in sandstone core type this change is considerable, but in highly artificial fractured sandstone with a high ratio of artificial fractured to sandstone absolute permeability ( K ef / K s ) is not substantial. Moreover the results show that in the described case of artificial fractured core type so simple conventional relative permeability methods have the same results compared to a sophisticated inverse modeling method. The other main result is the lack of miscibility activation in near miscible injection through the highly fractured reservoirs leading to viscose dominant flow rather than capillary. Finally by considering this changing behavior, a better knowledge of gas front movement through highly fractured reservoirs in low IFT regions can be obtained. [ABSTRACT FROM AUTHOR]

The process of producing dissolving pulp with SuperBatch cooking was introduced. The factors that affected the quality of the dissolving pulp and the corresponding operations were investigated. [ABSTRACT FROM AUTHOR]

A simple method for preparation of magnetic cellulose fibers by coating (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized viscose with oleic-acid-coated or uncoated, freshly prepared magnetic nanoparticles (MNp) is presented. MNp attachment was facilitated by chemical activation of the cellulose fibers through introduction of negatively charged carboxylic groups using the well-established TEMPO-mediated oxidation protocol. The resulting composite materials preserved the intrinsic properties of the cellulose fibers, but gained notable specific features due to the presence of magnetic nanoparticles. The obtained composite materials were characterized using spectral (Fourier-transform infrared spectroscopy) and microscopic (scanning electron microscopy) methods. Thermogravimetric analyses were carried out to evaluate the thermal stability of the magnetic fibers. The magnetic properties were evaluated using vibrating-sample magnetometry. [ABSTRACT FROM AUTHOR]

Flexible conductive devices were successfully fabricated through the layer-by- layer assembly of graphene oxide on the surface of viscose fibers followed by the reduction of graphene oxide to graphene. Viscose fibers with regions of low crystallinity played an important role in the distribution of reduced graphene oxide on the fiber surfaces. Scanning electron microscopy results demonstrated that graphene oxide could form uniform coatings with fewer cycles (<12), but exhibits the coating peeling or faulting over a greater number of cycles (>30). Owing to the presence of conductive coatings, the average volume resistivity value of the fabrics with fifty cycles could reach 33.31 Ω cm in the weft direction and 19.17 Ω cm in the warp direction, in contrast to the original fabric, which showed very little conductivity. Meanwhile, electrical resistivity tests of the fabrics under stretching and folding showed that minor changes in volume resistivity were observed when the change in the elongation rate of the fabrics was in the 0-15 % range and the folding angle of the fabrics was between 0° and 180°. Furthermore, such viscose fabrics with reduced graphene oxide layers showed improved hydrophobicity. For the fabric treated for five cycles, a water contact angle of 133.3° was achieved. The assembly of graphene oxide on the surface of viscose fibers provides an easy approach for the fabrication of flexible conductive devices with potential applications in solar cells, seawater desalination, wearable electronics, etc. [ABSTRACT FROM AUTHOR]

The upturn of viscose fiber market has triggered an augmented dissolving pulp usage over the last decade. Dissolving pulp is feasible to obtain from kraft pulp after two essential steps including hemicellulose removal and subsequent pulp activation. Prerequisite of conversion being hemicellulose reduction can be gently done by using xylanase treatment prior to alkali extraction. Herein, the significance of xylanase treatment and the optimum xylanase dose required in conjunction with subsequent alkali extraction was investigated. An increase in xylanase dose prior to alkali extraction had no significant effect on pentosans while the Fock reactivity and viscosity both improved at the dose of 50 AXU/g. Also, alkali extraction without xylanase pretreatment resulted in decreased Fock reactivity, alpha cellulose, brightness and viscosity of paper grade pulp. A moderate dose of xylanase prior to alkali extraction can thus be used to facilitate the hemicellulose removal while simultaneously protecting the native structure of cellulose. [ABSTRACT FROM AUTHOR]

An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions. [ABSTRACT FROM AUTHOR]