SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:0969 0239 OR L773:1572 882X "

Sökning: L773:0969 0239 OR L773:1572 882X

  • Resultat 1-50 av 329
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Jansson, Mikael, et al. (författare)
  • Upgrading of wood pre-hydrolysis liquor for renewable barrier design : a techno-economic consideration
  • 2014
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 21:3, s. 2045-2062
  • Tidskriftsartikel (refereegranskat)abstract
    • A techno-economic assessment of an upgrading procedure and outtake of a pre-hydrolysate in a presumed dissolving pulp mill was performed. Pre-hydrolysis of spruce wood chips in pilot scale produced input data for energy and mass balances and was performed with and without subsequent membrane filtration to produce hydrolysate fractions rich in galactoglucomannan and with some lignin. The hydrolysate is a viable raw material for the production of renewable thin oxygen barrier films as demonstrated herein in the formulation of free standing films with very low oxygen permeability at both moderate and high relative humidities. Approximately 50,000 ton dry solid upgraded pre-hydrolysate suitable for production of oxygen barriers could be produced according to the presumed dissolving pulp mill producing about 500,000 air dry ton dissolving pulp per year and applying a liquor to wood ratio of 4:1. Utilization of the pre-hydrolysis liquor hence adds value to and realizes the dissolving plant as a biorefinery. A sensitivity analysis indicates that the market price of the upgraded pre-hydrolysate has the largest positive effect on the return on investment for separation and upgrading of a pre-hydrolysate. Increased investment cost and increased annuity factor show negative effects.
  •  
2.
  • Aaen, Ragnhild, et al. (författare)
  • Combining cellulose nanofibrils and galactoglucomannans for enhanced stabilization of future food emulsions
  • 2021
  • Ingår i: Cellulose. - : Springer Science and Business Media B.V.. - 0969-0239 .- 1572-882X. ; 28:16, s. 10485-10500
  • Tidskriftsartikel (refereegranskat)abstract
    • The use of wood-derived cellulose nanofibrils (CNFs) or galactoglucomannans (GGM) for emulsion stabilization may be a way to obtain new environmentally friendly emulsifiers. Both have previously been shown to act as emulsifiers, offering physical, and in the case of GGM, oxidative stability to the emulsions. Oil-in-water emulsions were prepared using highly charged (1352 ± 5 µmol/g) CNFs prepared by TEMPO-mediated oxidation, or a coarser commercial CNF, less charged (≈ 70 µmol/g) quality (Exilva forte), and the physical emulsion stability was evaluated by use of droplet size distributions, micrographs and visual appearance. The highly charged, finely fibrillated CNFs stabilized the emulsions more effectively than the coarser, lower charged CNFs, probably due to higher electrostatic repulsions between the fibrils, and a higher surface coverage of the oil droplets due to thinner fibrils. At a constant CNF/oil ratio, the lowest CNF and oil concentration of 0.01 wt % CNFs and 5 wt % oil gave the most stable emulsion, with good stability toward coalescence, but not towards creaming. GGM (0.5 or 1.0 wt %) stabilized emulsions (5 wt % oil) showed no creaming behavior, but a clear bimodal distribution with some destabilization over the storage time of 1 month. Combinations of CNFs and GGM for stabilization of emulsions with 5 wt % oil, provided good stability towards creaming and a slower emulsion destabilization than for GGM alone. GGM could also improve the stability towards oxidation by delaying the initiation of lipid oxidation. Use of CNFs and combinations of GGM and CNFs can thus be away to obtain stable emulsions, such as mayonnaise and beverage emulsions. © 2021, The Author(s).
  •  
3.
  • Aaen, Ragnhild, et al. (författare)
  • The potential of TEMPO-oxidized cellulose nanofibrils as rheology modifiers in food systems
  • 2019
  • Ingår i: Cellulose. - : Springer Netherlands. - 0969-0239 .- 1572-882X. ; 26:9, s. 5483-5496
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract: Cellulose nanofibrils (CNFs) have been proposed for use in low-fat food products due to their availability and excellent viscosifying and gel forming abilities. As the CNFs are negatively charged, the presence of other components in foods, such as electrolytes and food additives such as xanthan gum is likely to affect their rheological properties. Hence, the study of these interactions can contribute valuable information of the suitability of CNFs as rheology modifiers and fat replacers. Rheological measurements on aqueous dispersions of TEMPO-oxidized CNFs were performed with variations in concentration of CNFs, concentration of electrolytes and with varying CNF/xanthan ratios. UV–Vis Spectroscopy was used to evaluate the onset of CNF flocculation/aggregation in the presence of electrolytes. The CNF dispersions followed a power-law dependency for viscosity and moduli on CNF concentration. Low electrolyte additions strengthened the CNF network by allowing for stronger interactions, while higher additions led to fibril aggregation, and loss of viscosity, especially under shear. The CNF/xanthan ratio, as well as the presence of electrolytes were shown to be key factors in determining whether the viscosity and storage modulus of CNF dispersions increased or decreased when xanthan was added. Graphical abstract: [Figure not available: see fulltext.].
  •  
4.
  • Agustin, Melissa B., et al. (författare)
  • Lignin nanoparticles as co-stabilizers and modifiers of nanocellulose-based Pickering emulsions and foams
  • 2023
  • Ingår i: Cellulose. - : Springer Nature. - 0969-0239 .- 1572-882X. ; 30:14, s. 8955-8971
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanocellulose is very hydrophilic, preventing interactions with the oil phase in Pickering emulsions. This limitation is herein addressed by incorporating lignin nanoparticles (LNPs) as co-stabilizers of nanocellulose-based Pickering emulsions. LNP addition decreases the oil droplet size and slows creaming at pH 5 and 8 and with increasing LNP content. Emulsification at pH 3 and LNP cationization lead to droplet flocculation and rapid creaming. LNP application for emulsification, prior or simultaneously with nanocellulose, favors stability given the improved interactions with the oil phase. The Pickering emulsions can be freeze–dried, enabling the recovery of a solid macroporous foam that can act as adsorbent for pharmaceutical pollutants. Overall, the properties of nanocellulose-based Pickering emulsions and foams can be tailored by LNP addition. This strategy offers a unique, green approach to stabilize biphasic systems using bio-based nanomaterials without tedious and costly modification procedures.
  •  
5.
  • Alakalhunmaa, Suvi, et al. (författare)
  • Softwood-based sponge gels
  • 2016
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:5, s. 3221-3238
  • Tidskriftsartikel (refereegranskat)abstract
    • Crosslinking-aided gelation was utilized to prepare hydrogels from softwood polysaccharides, with spruce galactoglucomannans (GGM)—a group of largely unexploited hemicelluloses—as the main component, aiming at conversion into sponge-like aerogels. Cellulose nanofibrils were used for the formation of a reinforcing network, which was further crosslinked together with a GGM matrix by ammonium zirconium carbonate, an inorganic salt that is regarded as safe for use in food packaging. The hydrogels were freeze-dried into stiff, low-density aerogels with 98 % of their volume composed of air-filled pores. When immersed in water, the aerogels absorbed water up to 37 times their initial weight, demonstrating elasticity and repeatable and reversible sponge capacity. The developed concept reassembles the wood polysaccharides in a new way, creating interesting possibilities for utilizing the abundant “green gold,” GGM. The obtained biobased materials could find application potential, for example, in the field of food packaging and could contribute in the reduction of the usage of petroleum-based plastics in the future.
  •  
6.
  • Albán Reyes, Diana Carolina, et al. (författare)
  • Is there a diffusion of alkali in the activation of dissolving cellulose pulp at low NAOH stoichiometric excess?
  • 2019
  • Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X. ; 26:2, s. 1297-1308
  • Tidskriftsartikel (refereegranskat)abstract
    • We conducted a quantitative study, following the degree of activation (i.e. the transformation to alkali cellulose, denoted as DoA) over time for dissolving cellulose pulp treated with different [NaOH] at low NaOH/anhydroglucose unit stoichiometric ratio (denoted as (r) ≤ 2.6). Our quantitative approach was based on Raman spectroscopy data, evaluated by partial least squares regression modelling. The results show strong influence of the (r) on DoA (increasing from DoA= 45% at (r) = 0.8, to DoA = 85% at (r) = 2.6), and its complex dependence on [NaOH]. At (r) = 0.8 the highest DoA (DoA ≳ 60%) was found at 30% [NaOH], while at (r) =1.3 it was found at 20% [NaOH] (DoA ≳ 80%). Although activation of cellulose happens in minutes at the studied temperature (30 °C), it was found that the reaction may be slow when a low (r) is used. A gradual increase of the DoA from ≈ 30% to ≈ 70% in time was seen when samples were activated with 30% [NaOH] at (r) = 0.8. At the same (r), a similar increase of DoA from ≈ 30 % to ≈ 60 % was also observed when 40% [NaOH] was used. Slow diffusion of NaOH through poorly swollen cellulose fibres is proposed as an explanation for this phenomenon. Lastly, solid-state CP/MAS NMR measurements suggest that at a fixed temperature, the Na-Cell allomorph mostly depends on [NaOH]. However, in the transition area between Na-Cell I and Na-Cell II, its influence might be affected by (r). 
  •  
7.
  • Albán Reyes, Diana Carolina, et al. (författare)
  • The influence of different parameters on the mercerisation of cellulose for viscose production
  • 2016
  • Ingår i: Cellulose. - : Springer Netherlands. - 0969-0239 .- 1572-882X. ; 23:2, s. 1061-1072
  • Tidskriftsartikel (refereegranskat)abstract
    • A quantitative analysis of degree of transformation from a softwood sulphite dissolving pulp to alkalised material and the yield of this transformation as a function of the simultaneous variation of the NaOH concentration, denoted [NaOH], reaction time and temperature was performed. Samples were analysed with Raman spectroscopy in combination with multivariate data analysis and these results were confirmed by X-ray diffraction. Gravimetry was used to measure the yield. The resulting data were related to the processing conditions in a Partial Least Square regression model, which made it possible to explore the relevance of the three studied variables on the responses. The detailed predictions for the interactive effects of the measured parameters made it possible to determine optimal conditions for both yield and degree of transformation in viscose manufacturing. The yield was positively correlated to the temperature from room temperature up to 45 A degrees C, after which the relation was negative. Temperature was found to be important for the degree of transformation and yield. The time to reach a certain degree of transformation (i.e. mercerisation) depended on both temperature and [NaOH]. At low temperatures and high [NaOH], mercerisation was instantaneous. It was concluded that the size of fibre particles (mesh range 0.25-1 mm) had no influence on degree of transformation in viscose processing conditions, apparently due to the quick reaction with the excess of NaOH.
  •  
8.
  • Aldaeus, Fredrik, et al. (författare)
  • The supramolecular structure of cellulose-rich wood pulps can be a determinative factor for enzymatic hydrolysability
  • 2015
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:6, s. 3991-4002
  • Tidskriftsartikel (refereegranskat)abstract
    • The enzymatic hydrolysability of three industrial pulps, five lab made pulps, and one microcrystalline cellulose powder was assessed using commercial cellulolytic enzymes. To gain insight into the factors that influence the hydrolysability, a thorough characterization of the samples was done, including their chemical properties (cellulose content, hemicellulose content, lignin content, and kappa number), their macromolecular properties (peak molar mass, number-average molar mass, weight-average molar mass, polydispersity, and limiting viscosity) and their supramolecular properties (fibre saturation point, specific surface area, average pore size, and crystallinity). The hydrolysability was assessed by determination of initial conversion rate and final conversion yield, with conversion yield defined as the amount of glucose in solution per unit of glucose in the substrate. Multivariate data analysis revealed that for the investigated samples the conversion of cellulose to glucose was mainly dependent on the supramolecular properties, such as specific surface area and average pore size. The molar mass distribution, the crystallinity, and the lignin content of the pulps had no significant effect on the hydrolysability of the investigated samples.
  •  
9.
  • Alexandrescu, Laura C., et al. (författare)
  • Cytotoxicity tests of cellulose nanofibril-based structures
  • 2013
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 20:4, s. 1765-1775
  • Tidskriftsartikel (refereegranskat)abstract
    • Cellulose nanofibrils based on wood pulp fibres are most promising for biomedical applications. Bacterial cellulose has been suggested for some medical applications and is presently used as wound dressing. However, cost-efficient processes for mass production of bacterial cellulose are lacking. Hence, fibrillation of cellulose wood fibres is most interesting, as the cellulose nanofibrils can efficiently be produced in large quantities. However, the utilization of cellulose nanofibrils from wood requires a thorough verification of its biocompatibility, especially with fibroblast cells which are important in regenerative tissue and particularly in wound healing. The cellulose nanofibril structures used in this study were based on Eucalyptus and Pinus radiata pulp fibres. The nanofibrillated materials were manufactured using a homogenizer without pre-treatment and with 2,2,6,6-tetramethylpiperidine-1-oxy radical as pre-treatment, thus yielding nanofibrils low and high level of anionic charge, respectively. From these materials, two types of nanofibril-based structures were formed; (1) thin and dense structures and (2) open and porous structures. Cytotoxicity tests were applied on the samples, which demonstrated that the nanofibrils do not exert acute toxic phenomena on the tested fibroblast cells (3T3 cells). The cell membrane, cell mitochondrial activity and the DNA proliferation remained unchanged during the tests, which involved direct and indirect contact between the nano-structured materials and the 3T3 cells. Some samples were modified using the crosslinking agent polyethyleneimine (PEI) or the surfactant cetyl trimethylammonium bromide (CTAB). The sample modified with CTAB showed a clear toxic behaviour, having negative effects on cell survival, viability and proliferation. CTAB is an antimicrobial component, and thus this result was as expected. The sample crosslinked with PEI also had a significant reduction in cell viability indicating a reduction in DNA proliferation. We conclude that the neat cellulose nanostructured materials tested in this study are not toxic against fibroblasts cells. This is most important as nano-structured materials based on nanofibrils from wood pulp fibres are promising as substrate for regenerative medicine and wound healing.
  •  
10.
  • Alimadadi, Majid, et al. (författare)
  • 3D-oriented fiber networks made by foam forming
  • 2016
  • Ingår i: Cellulose. - : Springer Netherlands. - 0969-0239 .- 1572-882X. ; 23:1, s. 661-671
  • Tidskriftsartikel (refereegranskat)abstract
    • In industrial applications, such as paper and nonwovens, cellulose fibers are used in the form of a network where the fibers are oriented more or less in the sheet-plane direction. However, in many biological systems, fibers are instead oriented in a three-dimensional (3D) space, creating a wide variety of functionalities. In this study we created a 3D-oriented fiber network on the laboratory scale and have identified some unique features of its structure and mechanical properties. The 3D fiber network sheets were prepared by using foam-forming as well as modifying consolidation and drying procedures. The fiber orientation and tensile/compression behavior were determined. The resulting sheets were extremely bulky (above 190 cm3/g) and had extremely low stiffness (or high softness) compared to the reference handsheets. Despite this high bulk, the sheets retained good structural integrity. We found that a 3D-oriented fiber network requires much less fiber-fiber contact to create a connected (“percolated”) network than a two-dimensionally oriented network. The compression behavior in the thickness direction was also unique, characterized by extreme compressibility because of its extreme bulk and a long initial increase in the compression load as well as high strain recovery after compression because of its fiber reorientation during compression.
  •  
11.
  • Alves, Luis, et al. (författare)
  • Dissolution state of cellulose in aqueous systems. 1. Alkaline solvents
  • 2016
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:1, s. 247-258
  • Tidskriftsartikel (refereegranskat)abstract
    • The understanding of the state of dissolution of cellulose in a certain solvent is a critical step forward in the development of new efficient solvent systems for cellulose. Nevertheless, obtaining such information is not trivial. Recently, polarization transfer solid-state NMR (PTssNMR) was shown to be a very promising technique regarding an efficient and robust characterization of the solution state of cellulose. In the present study, combining PTssNMR, microscopic techniques and X-ray diffraction, a set of alkaline aqueous systems are investigated. The addition of specific additives, such as urea or thiourea, to aqueous NaOH based systems as well as the use of an amphiphilic organic cation, is found to have pronounced effects on the dissolution efficiency of cellulose. Additionally, the characteristics of the regenerated material are strongly dependent on the dissolution system; typically less crystalline materials, presenting smoother morphologies, are obtained when amphiphilic solvents or additives are used.
  •  
12.
  • Amorim, Lúcia F.A., et al. (författare)
  • Sustainable bacterial cellulose production by low cost feedstock : evaluation of apple and tea by-products as alternative sources of nutrients
  • 2023
  • Ingår i: Cellulose. - : Springer Nature. - 0969-0239 .- 1572-882X. ; 30:9, s. 5589-5606
  • Tidskriftsartikel (refereegranskat)abstract
    • The high applicability of Bacterial Cellulose (BC) is often challenging due to its high production costs, which ultimately prevents its widespread use. Therefore, the present study aimed to investigate BC production using alternative feedstock to replace high-cost synthetic carbon and nitrogen sources and to evaluate the physical and structural properties of the produced BC membranes. BC was produced through a microbial consortium from kombucha, and the formulated alternative media sustained promising BC production, especially the association of apple wastes (at 10% (W/V)) with tea mixture, with a yield similar to BC produced on Hestrin–Schramm (HS) control media. Moreover, the BC samples produced in this alternative media also exhibited comparable properties to BC from HS media, with similar water-holding capacity and retention ability, thermal stability, mechanical behavior, and a crystallinity index of 87.61% and 88.08%, respectively. Thus, our findings substantiated that expensive substrates, such as glucose, peptone, and yeast extract, could be successfully replaced by apple wastes, black and green tea, for BC production while maintaining its remarkable physical and structural properties. Furthermore, besides the low-cost advantage, the bioconversion of apple waste also reduces the environmental burden caused by its disposal in landfills.
  •  
13.
  • Andreasson, B., et al. (författare)
  • Determination of fibre pore structure : influence of salt, pH and conventional wet strength resins
  • 2005
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 12:3, s. 253-265
  • Tidskriftsartikel (refereegranskat)abstract
    • It has been shown, in the present investigation, that the two methods used to investigate the pore size distribution of unbleached chemical pulps, i.e. inverse size exclusion chromatography (ISEC) and nuclear magnetic resonance (NMR), give different average pore radius for the pores inside the fibre wall. This is due to the way in which these experiments are performed and the sensitivity of the methods to different types of pores in the cell wall. It was also shown that the two methods gave different results when changing the pH and the ionic strength of the pulp suspension. The pore radius, as detected with ISEC, decreased with both increasing ionic strength and decreasing pH, indicating a loose structure of the exterior of the fibrillar network. However, the pore radius as detected with NMR, was virtually unaffected when increasing the ionic strength, indicating a very rigid structure of the interior of the fibre wall. Decreasing pH though, lead to a decrease in pore radius indicating that upon protonation of the carboxylic groups in the fibre wall, the electrostatic repulsion is diminished and the average pore radius decreases. The NMR technique was also used to study wet strength aid penetration into the fibre wall. It was shown that wet strength aids with a small molecular weight, penetrated the fibre wall, as detected by a decrease in pore radius. It was also shown that addition of different wet strength aids increased the tensile index of the sheet and decreased the fibre strength, measured as zero span-strength of the sheets.
  •  
14.
  • Andreasson, B., et al. (författare)
  • The porous structure of pulp fibres with different yields and its influence on paper strength
  • 2003
  • Ingår i: Cellulose. - 0969-0239 .- 1572-882X. ; 10:2, s. 111-123
  • Tidskriftsartikel (refereegranskat)abstract
    • The porous structure of the interior of papermaking fibres is a well-known important property of the fibres. Changes of this structure will influence tensile and burst strength of paper formed from the fibres and a change in pore size of the pores within the fibre wall is also important for the ability of molecules to diffuse in and out of the fibre wall. Relevant examples of this latter effect are the removal of lignin during cooking and the addition of performance chemicals during papermaking. In this paper, pore sizes and the pore size distribution of unbleached softwood fibres have been studied. A well-characterised fibre material consisting of laboratory cooked spruce and pine pulp of various lignin contents was used. Pore size and pore size distribution were measured by studies of the relaxation behaviour of H-2 in fibres saturated with (H2O)-H-2. Beside this the total and surface charge of the fibres were also measured together with strength properties of papers from unbeaten fibres. For both pulps, there is a maximum in pore radius at a yield around 46%. Calculations of fibre wall volume from water retention values and yield levels show that there is a discontinuity in pore radius as a function of the fibre wall volume around a yield of 51%. It is suggested that this discontinuity is caused by the breakdown of the hemicellulose/ lignin matrix within the fibre wall at this yield level. The strength of the papers formed from the fibres shows a correlation with the surface charge of the fibres. Based on the change in surface charge with yield and the change in total charge with yield, this correlation is suggested to be due to an opening up of the external part of the fibre wall. This stresses the importance of the chemical composition and physical structure of the outer layer of the fibre wall.
  •  
15.
  • Apostolopoulou-Kalkavoura, Varvara, 1988-, et al. (författare)
  • Thermal conductivity of hygroscopic foams based on cellulose nanofibrils and a nonionic polyoxamer
  • 2018
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 25:2, s. 1117-1126
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanocellulose-based lightweight foams are promising alternatives to fossil-based insulation materials for energy-efficient buildings. The properties of cellulose-based materials are strongly influenced by moisture and there is a need to assess and better understand how the thermal conductivity of nanocellulose-based foams depends on the relative humidity and temperature. Here, we report a customized setup for measuring the thermal conductivity of hydrophilic materials under controlled temperature and relative humidity conditions. The thermal conductivity of isotropic foams based on cellulose nanofibrils and a nonionic polyoxamer, and an expanded polystyrene foam was measured over a wide range of temperatures and relative humidity. We show that a previously developed model is unable to capture the strong relative humidity dependence of the thermal conductivity of the hygroscopic, low-density nanocellulose- and nonionic polyoxamer-based foam. Analysis of the moisture uptake and moisture transport was used to develop an empirical model that takes into consideration the moisture content and the wet density of the investigated foam. The new empirical model could predict the thermal conductivity of a foam with a similar composition but almost 3 times higher density. Accurate measurements of the thermal conductivity at controlled temperature and relative humidity and availability of simple models to better predict the thermal conductivity of hygroscopic, low-density foams are necessary for the development of nanocellulose-based insulation materials.
  •  
16.
  • Aulin, Christian, et al. (författare)
  • Oxygen and oil barrier properties of microfibrillated cellulose films and coatings
  • 2010
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 17:3, s. 559-574
  • Tidskriftsartikel (refereegranskat)abstract
    • The preparation of carboxymethylated microfibrillated cellulose (MFC) films by dispersion-casting from aqueous dispersions and by surface coating on base papers is described. The oxygen permeability of MFC films were studied at different relative humidity (RH). At low RH (0%), the MFC films showed very low oxygen permeability as compared with films prepared from plasticized starch, whey protein and arabinoxylan and values in the same range as that of conventional synthetic films, e.g., ethylene vinyl alcohol. At higher RH's, the oxygen permeability increased exponentially, presumably due to the plasticizing and swelling of the carboxymethylated nanofibers by water molecules. The effect of moisture on the barrier and mechanical properties of the films was further studied using water vapor sorption isotherms and by humidity scans in dynamic mechanical analysis. The influences of the degree of nanofibrillation/dispersion on the microstructure and optical properties of the films were evaluated by field-emission scanning electron microscopy (FE-SEM) and light transmittance measurements, respectively. FE-SEM micrographs showed that the MFC films consisted of randomly assembled nanofibers with a thickness of 5-10 nm, although some larger aggregates were also formed. The use of MFC as surface coating on various base papers considerably reduced the air permeability. Environmental scanning electron microscopy (E-SEM) micrographs indicated that the MFC layer reduced sheet porosity, i.e., the dense structure formed by the nanofibers resulted in superior oil barrier properties.
  •  
17.
  • Auvinen, VV, et al. (författare)
  • Nanoparticle release from anionic nanocellulose hydrogel matrix
  • 2022
  • Ingår i: CELLULOSE. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 29:18, s. 9707-9717
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Nanocellulose hydrogels have been shown to be excellent platforms for sustained delivery of drug molecules. In this study, we examine the suitability of anionic nanocellulose hydrogels for the sustained release of various nanoparticles. Systems releasing nanoparticles could produce applications especially for therapeutic nanocarriers, whose life-times in vivo might be limited. Micelles, liposomes and DNA origami nanostructures were incorporated into the nanocellulose hydrogels, and their release rates were measured. Two different hydrogel qualities (with 1% and 2% mass of fiber content) were used for each nanoparticle formulation. We showed that the drug release rates depend on nanoparticle size, shape, and charge. Smaller particles with neutral charge were released faster from 1% hydrogels than from 2% hydrogels. Nanoparticles with cationic labeling were retained in both hydrogels, whereas for the neutral nanoparticles, we were able to determine the cut-off size for released particles for both hydrogels. Rod-shaped DNA origami were released rapidly even though their length was above the cut-off size of spherical particles, indicating that their smaller radial dimension facilitates their fast release. Based on our results, anionic nanocellulose hydrogels are versatile platforms for the sustained release of the chosen model nanoparticles (liposomes, micelles, and DNA origami). Alternatively, for the tightly bound nanoparticles, this could lead to nanoparticle reservoirs within hydrogels, which could act as immobilized drug release systems.
  •  
18.
  • Ayoub, Ali, et al. (författare)
  • Effect of plasticizers and polymer blends for processing softwood kraft lignin as carbon fiber precursors
  • 2021
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 28:2, s. 1039-1053
  • Tidskriftsartikel (refereegranskat)abstract
    • Plasticizers depress the glass transition temperature (T-g) of polymers and produce a flowable material at lower temperatures. The use of plasticizers to depress T-g of lignin is important, since at high processing temperatures lignin crosslinks, making it intractable. The goal of this study was to assess plasticizers and polymer blends for the ability to retard a commercial softwood kraft lignin from crosslinking and also serve as thermal and rheological property modifiers during thermal processing in the attempt to produced moldable and spinnable lignin for lignin and carbon fiber products. The T-g of the lignin and the lignin mixed with various amounts of plasticizers and with different thermo-mechanical mixing were determined using differential scanning calorimetry. The T-g and the change in heat capacity at the glass transition (Delta C-p) decreased and increased, respectively, about linearly within this plasticizers range with increased plasticizer weight percentage. Gel permeation chromatography results for extruded lignin as well as extruded lignin-plasticizer blends with glycerol, N-allyurea, citric acid with and without sodium hypophosphite, and oleic acid indicate that the presence of these materials reduced the rate of molecular weight increase at temperatures between 100 and 200 degrees C. Continuous, homogenous films and fibers could be produced by thermal processing with plasticized lignin samples and plasticized lignin-polymer blends, but not with lignin alone. These fibers could be carbonized, yielding up to about 50% of carbon. The present findings have shown the advantages of plasticizers in thermally processing a commercial softwood kraft lignin.
  •  
19.
  • Bardet, Raphael, et al. (författare)
  • Substitution of nanoclay in high gas barrier films of cellulose nanofibrils with cellulose nanocrystals and thermal treatment
  • 2015
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:2, s. 1227-1241
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study is to design a nanocellulose based barrier film. For this purpose, cellulose nanofibrils (CNFs) are used as a matrix to create an entangled nanoporous network that is filled with two different nanofillers: nanoclay (reference), i.e. the mineral montmorillonite (MMT) and the bio-based TEMPO-oxidized cellulose nanocrystal (CNC-T), to produce different types of nanocelluloses and their main physical and chemical features were assessed. As expected, films based on neat CNFs exhibit good mechanical performance and excellent barrier properties at low moisture content. The introduction of 32.5 wt% of either nanofiller results in a significant improvement of barrier properties at high moisture content. Finally, thermal treatment of a dried CNF/CNC-T film results in a decrease of the oxygen permeability even at high moisture content (>70 %). This is mainly attributed to the hornification of nanocellulose. A key result of this study is that the oxygen permeability of an all-nanocellulose film in 85 % relative humidity (RH), is similar to CNF film with mineral nanoclay (MMT), i.e. 2.1 instead of 1.7 cm3 µm m−2 day−1 kPa−1, respectively.
  •  
20.
  • Bengtsson, Jenny, et al. (författare)
  • Revealing pore size distribution in cellulose and lignin-cellulose man-made fibers – effect of draw ratio and lignin content
  • 2024
  • Ingår i: Cellulose. - : Springer Science and Business Media B.V.. - 0969-0239 .- 1572-882X.
  • Tidskriftsartikel (refereegranskat)abstract
    • There are limited methods available for measurement of the porosity of cellulose fibers, even more so for obtaining a pore size distribution. Conventional pore analysis methods require dry samples, with intact pores. However, pores in cellulose fibers collapse when dried from water and thus present a challenge for sample analysis. Furthermore, the pore collapse is partially irreversible which should be accounted for in the analysis. In this study, analysis of pore structure was carried out in the wet state with thermoporometry and also for critical point dried samples, analyzed with N2 sorption. This study determines the effect of fiber lignin content and certain spinning parameters on the pore size distribution of spun fibers before and after drying. It could also be concluded that solvent exchange, drying from a non-polar solvent will result in an altered pore size distribution, with a total pore volume greater than if dried from water, however not representative of the never-dried state. It is concluded that thermoporometry together with the water retention value (WRV) measurement is a powerful combination to acquire insights to the pore size distribution of spun fiber. 
  •  
21.
  • Bergenstrahle-Wohlert, Malin, et al. (författare)
  • On the anomalous temperature dependence of cellulose aqueous solubility
  • 2016
  • Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X. ; 23:4, s. 2375-2387
  • Tidskriftsartikel (refereegranskat)abstract
    • The solubility of cellulose in water-based media is promoted by low temperature, which may appear counter-intuitive. An explanation to this phenomenon has been proposed that is based on a temperature-dependent orientation of the hydroxymethyl group. In this paper, this hypothesis is investigated using molecular dynamics computer simulations and NMR spectroscopy, and is discussed in conjunction with alternative explanations based on solvent–solute and solvent–solvent hydrogen bond formation respectively. It is shown that neither simulations nor experiments lend support to the proposed mechanism based on the hydroxymethyl orientation, whereas the two alternative explanations give rise to two distinct contributions to the hydration free energy of cellooligomers.
  •  
22.
  • Bergenstråhle-Wohlert, Malin, et al. (författare)
  • Concentration enrichment of urea at cellulose surfaces : results from molecular dynamics simulations and NMR spectroscopy
  • 2012
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 19:1, s. 1-12
  • Tidskriftsartikel (refereegranskat)abstract
    • A combined solid-state NMR and Molecular Dynamics simulation study of cellulose in urea aqueous solution and in pure water was conducted. It was found that the local concentration of urea is significantly enhanced at the cellulose/solution interface. There, urea molecules interact directly with the cellulose through both hydrogen bonds and favorable dispersion interactions, which seem to be the driving force behind the aggregation. The CP/MAS (13)C spectra was affected by the presence of urea at high concentrations, most notably the signal at 83.4 ppm, which has previously been assigned to C4 atoms in cellulose chains located at surfaces parallel to the (110) crystallographic plane of the cellulose I beta crystal. Also dynamic properties of the cellulose surfaces, probed by spin-lattice relaxation time (13)CT (1) measurements of C4 atoms, are affected by the addition of urea. Molecular Dynamics simulations reproduce the trends of the T (1) measurements and lends new support to the assignment of signals from individual surfaces. That urea in solution is interacting directly with cellulose may have implications on our understanding of the mechanisms behind cellulose dissolution in alkali/urea aqueous solutions.
  •  
23.
  • Berglund, Jennie, et al. (författare)
  • The structure of galactoglucomannan impacts the degradation under alkaline conditions
  • 2018
  • Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X.
  • Tidskriftsartikel (refereegranskat)abstract
    • Galactoglucomannan (GGM) from sprucewas studied with respect to the degradation behavior inalkaline solution. Three reference systems includinggalactomannan from locust bean gum, glucomannanfrom konjac and the linear water-soluble carboxymethylcellulose were studied with focus onmolecular weight, sugar composition, degradationproducts, as well as formed oligomers, to identifyrelative structural changes in GGM. Initially allmannan polysaccharides showed a fast decrease inthe molecular weight, which became stable in the laterstage. The degradation of the mannan polysaccharidescould be described by a function corresponding to thesum of two first order reactions; one slow that wasascribed to peeling, and one fast that was connectedwith hydrolysis. The galactose side group wasstable under conditions used in this study (150 min,90 C, 0.5 M NaOH). This could suggest that, apartfrom the covalent connection to C6 in mannose, thegalactose substitutions also interact non-covalentlywith the backbone to stabilize the structure againstdegradation. Additionally, the combination of differentbackbone sugars seems to affect the stability of thepolysaccharides. For carboxymethyl cellulose thedegradation was linear over time which furthersuggests that the structure and sugar composition playan important role for the alkaline degradation. Moleculardynamics simulations gave details about theconformational behavior of GGM oligomers in watersolution, as well as interaction between the oligomersand hydroxide ions.
  •  
24.
  • Berglund, Linn, et al. (författare)
  • Switchable ionic liquids enable efficient nanofibrillation of wood pulp
  • 2017
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 24:8, s. 3265-3279
  • Tidskriftsartikel (refereegranskat)abstract
    • Use of switchable ionic liquid (SIL) pulp offers an efficient and greener technology to produce nanofibers via ultrafine grinding. In this study, we demonstrate that SIL pulp opens up a mechanically efficient route to the nanofibrillation of wood pulp, thus providing both a low cost and chemically benign route to the production of cellulose nanofibers. The degree of fibrillation during the process was evaluated by viscosity and optical microscopy of SIL treated, bleached SIL treated and a reference pulp. Furthermore, films were prepared from the fibrillated material for characterization and tensile testing. It was observed that substantially improved mechanical properties were attained as a result of the grinding process, thus signifying nanofibrillation. Both SIL treated and bleached SIL treated pulps were fibrillated into nanofibers with fiber diameters below 15 nm thus forming networks of hydrophilic nature with an intact crystalline structure. Notably, it was found that the SIL pulp could be fibrillated more efficiently than traditional pulp since nanofibers could be produced with more than 30% less energy when compared to the reference pulp. Additionally, bleaching reduced the energy demand by further 16%. The study demonstrated that this switchable ionic liquid treatment has considerable potential in the commercial production of nanofibers due to the increased efficiency in fibrillation.
  •  
25.
  • Bergström, L, et al. (författare)
  • Spectroscopic ellipsometry characterisation and estimation of the Hamaker constant of cellulose
  • 1999
  • Ingår i: Cellulose. - 0969-0239 .- 1572-882X. ; 6, s. 1-13
  • Tidskriftsartikel (refereegranskat)abstract
    • Calculations of Hamaker constants using Lifshitz theory require the availability of accurate dielectric data, especially in the visible-ultraviolet region. We present spectroscopic ellipsometry data on well defined cellulose films of a limited thickness range (100–140 layers) deposited on an oxidised and hydrophobised silicon substrate. The spectral data, representing measurements from a perpendicular orientation to the fibre deposition direction, was used for estimates of the necessary spectral parameters, i.e. the oscillator strengths and characteristic frequencies in the UV-range. Our calculations show that cellulose has a relatively low Hamaker constant in air (58 zJ) and water (8.0 zJ). The implications for the surface energy estimates of cellulose and colloidal interactions between cellulose and various types of fillers and coating colours were discussed.
  •  
26.
  • Bialik, Marta, et al. (författare)
  • Design, optimization and modelling of a chemical recovery system for wet spinning of cellulose in sodium carbonate solutions
  • 2020
  • Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X. ; 27, s. 8681-8693
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study is to present the design, optimization and modelling of a chemical recovery system for a novel CS2-free viscose-type process that entails dissolution of pre-treated dissolving pulp in a continuous-flow reactor in cold alkali and wet spinning of cellulose in sodium carbonate solutions. Technologies already known to other industries for the recovery and reuse of chemicals, such as causticizing, recalcination, recarbonization and freeze-separation, were used. Chemical equilibria simulations were performed with OLI Studio 9.5, with the purpose to select experimental conditions which avoid undesired precipitations in each unit operation. Synthetic solutions mimicking the spent coagulation liquor were used in the laboratorial experiments. The proposed chemical recovery system was shown to be technically feasible and reduce chemical make-ups to a minimum of 45 kg/ton of NaOH and 4 kg/ton of H2SO4. Small amounts of Zn are expected to precipitate during recarbonization of the coagulation liquor at 30 °C and causticizing at 98 °C. Thus, a filter for ZnO particles should be included in the design of the recarbonization unit and a continuous purge of lime mud and input of fresh lime make-up should be needed to keep burnt lime availability at an acceptable level. Overall, the results presented in this study portray a solution to reduce operating costs and the environmental impact of novel viscose-type processes with alkaline spin dopes and wet spinning of cellulose in sodium carbonate solutions. © 2020, The Author(s).
  •  
27.
  • Bondeson, Daniel, et al. (författare)
  • Optimization of the Isolation of Nanocrystals from Microcrystalline Cellulose by Acid Hydrolysis
  • 2006
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 13:2, s. 171-180
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this work was to find a rapid, high-yield process to obtain an aqueous stable colloid suspension of cellulose nanocrystals/whiskers. Large quantities are required since these whiskers are designed to be extruded into polymers in the production of nano-biocomposites. Microcrystalline cellulose (MCC), derived from Norway spruce (Picea abies), was used as the starting material. The processing parameters have been optimized by using response surface methodology. The factors that varied during the process were the concentration of MCC and sulfuric acid, the hydrolysis time and temperature, and the ultrasonic treatment time. Responses measured were the median size of the cellulose particles/whiskers and yield. The surface charge as calculated from conductometric titration, microscopic examinations (optical and transmission electron microscopy), and observation of birefringence were also investigated in order to determine the outcome (efficiency) of the process. With a sulfuric acid concentration of 63.5% (w/w), it was possible to obtain cellulose nanocrystals/whiskers with a length between 200 and 400 nm and a width less than 10 nm in approximately 2 h with a yield of 30% (of initial weight).
  •  
28.
  • Bozic, Mojca, et al. (författare)
  • Enzymatic phosphorylation of cellulose nanofibers to new highly-ions adsorbing, flame-retardant and hydroxyapatite-growth induced natural nanoparticles
  • 2014
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 21:4, s. 2713-2726
  • Tidskriftsartikel (refereegranskat)abstract
    • This study confirms the enzyme-mediated phosphorylation of cellulose nanofibers (CNF) by using hexokinase and adenosine-5’-triphosphate (ATP) in the presence of Mg-ions, resulting in a phosphate group’s creation predominantly at C-6-O positioned hydroxyl groups of cellulose monomer rings. A proof-of-concept is provided using 12C CPMAS, 31P MAS NMR, ATR-FTIR and XPS analyzing methods. The degree of substitution is determined for the first time by ATR-FTIR spectroscopy being in a correlation with XPS and potentiometric titration results. From the thermal degradation measurements using TGA, the C-6-O phosphorylation was found to noticeably prevent the CNF derivatives from weight loss in the pyrolysis process, thus, providing them flame-resistance functionality. Furthermore, phosphorylation significantly enhanced adsorption capacity of Fe3+ ions making them interesting for fabrication of biobased filters and membranes. Finally, the biomimetic growth of Ca-P crystals (hydroxyapatite) in simulated body fluid was characterized by SEM and showing further practicability for biomedical materials.
  •  
29.
  • Brandberg, August, 1990-, et al. (författare)
  • Compression failure in dense non-woven fiber networks
  • 2020
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 27:10, s. 6065-6082
  • Tidskriftsartikel (refereegranskat)abstract
    • Investigating the compression properties of randomly ordered fiber networks experimentally is difficult which has resulted in ongoing disputes as to the mechanisms controlling the compression strength in such materials. In this work, we investigated compression properties of randomly oriented fiber networks with a special emphasis on cellulose products such as paperboard. We numerically reconstructed the conditions of the short span compression test widely used to quantify the compression strength of paperboard. We found that the phenomenological failure mode of such networks is elasto-plastic buckling. The x-shaped failure mode observed in physical experiments appears when test specimen restraints are included in the model. The most significant improvements to sheet strength can be obtained by improving the elastic properties while the strain to failure is increased most by an improvement of the plastic yield and hardening properties of individual fibers. Bond breaks were confirmed to have a smaller influence on the overall response. Fiber level microscopic buckling was investigated in depth, providing quantitative estimates of the fraction of mass likely to buckle at the microscopic level. The analysis indicated that only a low to moderate number of load carrying fibers can be expected to buckle. The inherent strength reserve in non-ordered fiber networks was investigated by introducing hinge mechanisms throughout the network, and the effect was shown to be small for a small to moderate number of hinges.
  •  
30.
  • Brännvall, Elisabet, 1961-, et al. (författare)
  • Analysis of entrapped and free liquor to gain new insights into kraft pulping
  • 2021
  • Ingår i: Cellulose. - : Springer Science and Business Media B.V.. - 0969-0239 .- 1572-882X. ; 28, s. 2403-2418
  • Tidskriftsartikel (refereegranskat)abstract
    • Most of our knowledge on kraft pulping comes from studies on dissolved lignin in the freely drainable black liquor and isolated residual lignin in pulp. However, entrapped liquor in the delignified chips has been shown to differ significantly from the free liquor. The present study has compared three liquor fractions: free, lumen and fiber wall liquor. The free liquor was obtained by draining the delignified chips, the lumen liquor was separated by centrifugation and the fiber wall liquor by subsequent leaching. The liquor in the fiber wall had the lowest concentration of lignin and hydrosulfide ions and the highest concentration of monovalent cations. The dissolved lignin in the fiber wall liquor had the highest molar mass and the highest content of xylan. The highest concentration of dissolved lignin was in the liquor filling the lumen cavities. The lignin in the free liquor had the lowest molar mass and the lowest content of lignin structures containing β-O-4 linkages and aliphatic hydroxyl groups. The lowest mass transfer rate of dissolved lignin was from the lumen liquor to the free liquor probably restricted by the tortuosity of the chip. 
  •  
31.
  • Brännvall, Elisabet, 1961-, et al. (författare)
  • Changes in the cellulose fiber wall supramolecular structure during the initial stages of chemical treatments of wood evaluated by NMR and X-ray scattering
  • 2021
  • Ingår i: Cellulose. - : Springer Science and Business Media B.V.. - 0969-0239 .- 1572-882X. ; 28, s. 3951-3965
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of initial stages of pulping of spruce, resembling prehydrolysis and alkaline cooking was studied using CP/MAS 13C-NMR, X-ray scattering, FSP and carbohydrate composition in order to study the impact of the pre-treatments on the fiber wall nanostructure. Removal of fiber wall components, hemicellulose and lignin, increased the fiber wall porosity and induced cellulose fibril aggregation. The effect of temperature and pH in the treatment on cellulose fibril aggregate size appears to be secondary. It is the removal of hemicellulose that has a profound effect on the supramolecular structure of the cellulose fiber wall. As the amount of hemicellulose dissolved from wood increases, the fibril aggregate size determined by NMR increases as well, ranging from 16 to 28 nm. Specifically, a good correlation between the amount of glucomannan in the fiber wall and the fibril aggregate size is seen. The lower the amount of glucomannan, the larger the aggregate size. Glucomannan thus seems to prevent aggregation as it acts as a very efficient spacer between fibrils. Elemental fibril size determined by NMR, was quite similar for all samples, ranging from 3.6 to 4.1 nm. By combining measurement methods, a more well-resolved picture of the structural changes occurring during was obtained. © 2021, The Author(s).
  •  
32.
  • Brännvall, Elisabet, 1961-, et al. (författare)
  • CNFs from softwood pulp fibers containing hemicellulose and lignin
  • 2022
  • Ingår i: Cellulose. - : Springer Science and Business Media B.V.. - 0969-0239 .- 1572-882X.
  • Tidskriftsartikel (refereegranskat)abstract
    • The energy demand to produce cellulose nanofibrils, CNFs, is high and additionally the cost of the starting material, the pulp, is substantial as high purity cellulose dissolving pulp is generally used. Pulps aimed for board and paper are produced at higher yield as they contain hemicelluloses and, in the case of unbleached pulp, lignin, and would be a more economical starting material for CNFs. It is of interest to understand how the presence of hemicellulose and lignin affects the fibrillation process and CNF properties. Kraft cooks of softwood were performed as well as kraft cooks with addition of polysulfide to increase the hemicellulose content. Part of the pulps were bleached to remove residual lignin, thus making it possible to compare pulps with and without lignin. Higher amount of hemicellulose had an obstructive effect on the enzymatic pre-treatment whereas lignin had no adverse effect on enzyme accessibility. Increased amount of charged groups improved the accessibility for enzymes. Both hemicellulose and lignin were carboxymethylated when pre-treatment by carboxymethylation was employed. However, carboxymethylation partly dissolved hemicelluloses. The tensile strength of CNF films was independent of the chemical composition of the pulp and the pre-treatment strategy. However, since the enzymatic pre-treatment decreased the cellulose DP more, CNF films from enzymatically pre-treated pulps had generally lower tensile strength. © 2022, The Author(s).
  •  
33.
  • Butchosa, Nuria, et al. (författare)
  • Stronger cellulose microfibril network structure through the expression of cellulose-binding modules in plant primary cell walls
  • 2019
  • Ingår i: Cellulose. - : SPRINGER. - 0969-0239 .- 1572-882X. ; 26:5, s. 3083-3094
  • Tidskriftsartikel (refereegranskat)abstract
    • Cellulose-binding modules (CBMs) are non-catalytic domains typically occurring in glycoside hydrolases. Their specific interaction with diverse polysaccharides assists hydrolysis by the catalytic subunits. In this work, we have exploited the interactions between a CBM from family 3 (CBM3) and cell wall polysaccharides to alter the structure and mechanical properties of cellulose microfibrils from BY-2 tobacco cell suspension cultures. A CBM3 from Clostridium thermocellum was overexpressed in the cells using Agrobacterium-mediated transformation. Water suspensions of cellulose microfibrils were prepared by the removal of the non-cellulosic components of the primary cell walls, followed by mild disintegration using sonication. The morphology of the microfibrils was characterized by transmission electron microscopy and atomic force microscopy. These cellulose microfibrils were further hydrolyzed with 64wt% sulfuric acid to produce cellulose nanocrystals (CNCs). The average length of CNCs prepared from the CBM3-transformed cells was 201nm, higher than that from the wild-type cells (122nm). In addition, the mechanical properties and deformation mechanism of nanopapers prepared from suspensions of cellulose microfibrils were investigated. The nanopapers obtained from the CBM3-transformed cells exhibited enhanced tensile strength and work of fracture, 40% and 128% higher than those prepared from wild-type tobacco cells, respectively. [GRAPHICS] .
  •  
34.
  • Butchosa, Núria, et al. (författare)
  • Water redispersible cellulose nanofibrils adsorbed with carboxymethyl cellulose
  • 2014
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 21:6, s. 4349-4358
  • Tidskriftsartikel (refereegranskat)abstract
    • Cellulose nanofibrils (CNFs) are difficult to redisperse in water after they have been completely dried due to the irreversible agglomeration of cellulose during drying. Here, we have developed a simple process to prepare water-redispersible dried CNFs by the adsorption of small amounts of carboxymethyl cellulose (CMC) and oven drying. The adsorption of CMC onto CNFs in water suspensions at 22 and 121 °C was studied, and the adsorbed amount of CMC was measured via conductimetric titration. The water-redispersibility of dried CNFs adsorbed with different amounts of CMC was characterized by sedimentation test. Above a critical threshold of CMC adsorption, i.e. 2.3 wt%, the oven dried CNF–CMC sample was fully redispersible in water. The morphology, rheological, and mechanical properties of water-redispersed CNF–CMC samples were investigated by field emission scanning electron microscopy, viscosity measurement, and tensile test, respectively. The water-redispersed CNFs preserved the original properties of never dried CNFs. This new method will facilitate the production, transportation and storage, and large-scale industrial applications of CNFs.
  •  
35.
  • Bågenholm-Ruuth, Edvin, et al. (författare)
  • Transforming post-consumer cotton waste textiles into viscose staple fiber using hydrated zinc chloride
  • 2024
  • Ingår i: Cellulose. - : Springer Science and Business Media B.V.. - 0969-0239 .- 1572-882X. ; 31:2, s. 737-748
  • Tidskriftsartikel (refereegranskat)abstract
    • Large amounts of cellulose-based waste textiles are generated every year, yet little is done to recycle this waste. Alternatives such as fiber-to-fiber recycling, where a significant part of the value of the waste textiles is recovered, are attractive possibilities. In this study, we have investigated the viability of using hydrated zinc chloride (ZnCl2·4H2O) as a solvent and swelling agent to convert cotton waste textiles (the most abundant cellulose-based waste textile) into a dissolving pulp that can be used as raw material for the production and spinning of viscose fibers. The solvent produced an accessible dissolving pulp and exhibited excellent recyclability, maintaining good dissolving power even after repeated recycling. The dissolving pulp was subsequently used to produce viscose dope, a spinning solution which was spun and cut into viscose staple fibers. The viscose dope exhibited good properties (moderate filter clogging value and gamma number), and the resulting staple fibers were strong and of good quality (high linear density, elongation, and tenacity). These results illustrate the potential of using hydrated zinc chloride for the production of viscose grade dissolving pulp from cotton waste textiles. 
  •  
36.
  • Cárdenas Bates, Ilse Ileana, et al. (författare)
  • Cellulose reinforced electrospun chitosan nanofibers bio-based composite sorbent for water treatment applications
  • 2021
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; :28, s. 4865-4885
  • Tidskriftsartikel (refereegranskat)abstract
    • Electrospun chitosan-polyethylene oxide/TEMPO-oxidized cellulose (CS-PEO/TOC) bio-based composite was fabricated for the first time for water treatment applications. This new concept allows cellulose and chitosan to be combined in a simpler and efficient way, avoiding the use of harmful solvents, compared to previously published related work. The Sandwich-like material is composed of a porous oxidized cellulosic fibers central core (TOC handsheet) and a thin layer of electrospun CS-PEO nanofibers on both sides of the core. Average diameters for CS-PEO and TOC were 159.3 +/- 33.7 nm and 21.7 +/- 5.1 mu m, respectively. Fourier Transform Infrared Spectroscopy (FTIR) was carried out on the bio-based composite. Results suggest that no covalent bonds are involved but rather electrostatic interactions occur which allows bonding of the electrospun nanofiber layers on TOC core and no delamination. CS-PEO electrospinning time was varied to study the effect of nanofiber's coating weight on strength, permeability and adsorption capacity of the bio-based material. Mechanical properties of the composite were improved over the electrospun nanofiber mat. The CS-PEO provides greater elasticity (strain%) and the TOC provides a higher tensile strength to the material. However, tensile index was reduced by 48% with electrospinning time, while burst index was almost constant. The best conditions were achieved for 2 h electrospinning time. Under these conditions, a high permeable material (290.13 L/m(2) hbar) was developed. The adsorption capacity for Cu (II) ions reached up to 27% with only 12 mg of chitosan onto the CS-PEO/TOC (12.42 mg/g). The data fit better to the pseudo-second order model, suggesting chemisorption as the main mechanism involved for copper adsorption. This study opens-up potential opportunities for the development of a robust material for wastewater applications at an industrial scale.
  •  
37.
  • Carlsson, Linn, et al. (författare)
  • Surface characteristics of cellulose nanoparticles grafted by surface-initiated ring-opening polymerization of epsilon-caprolactone
  • 2015
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:2, s. 1063-1074
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, surface-initiated ring-opening polymerization has been employed for the grafting of epsilon-caprolactone from cellulose nanoparticles, made by partial hydrolysis of cellulose cotton linters. A sacrificial initiator was employed during the grafting reactions, to form free polymer in parallel to the grafting reaction. The degree of polymerization of the polymer grafts, and of the free polymer, was varied by varying the reaction time. The aim of this study was to estimate the cellulose nanoparticle degree of surface substitution at different reaction times. This was accomplished by combining measurement results from spectroscopy and chromatography. The prepared cellulose nanoparticles were shown to have 3.1 (+/- 0.3) % of the total anhydroglucose unit content present at the cellulose nanoparticle surfaces. This effectively limits the amount of cellulose that can be targeted by the SI-ROP reactions. For a certain SI-ROP reaction time, it was assumed that the resulting degree of polymerization (DP) of the grafts and the DP of the free polymer were equal. Based on this assumption it was shown that the cellulose nanoparticle surface degree of substitution remained approximately constant (3-7 %) and seemingly independent of SI-ROP reaction time. We believe this work to be an important step towards a deeper understanding of the processes and properties controlling SI-ROP reactions occurring at cellulose surfaces.
  •  
38.
  • Cervin, Nicholas Tchang, et al. (författare)
  • Ultra porous nanocellulose aerogels as separation medium for mixtures of oil/water liquids
  • 2012
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 19:2, s. 401-410
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel type of sponge-like material for the separation of mixed oil and water liquids has been prepared by the vapour deposition of hydrophobic silanes on ultra-porous nanocellulose aerogels. To achieve this, a highly porous (> 99%) nanocellulose aerogel with high structural flexibility and robustness is first formed by freeze-drying an aqueous dispersion of the nanocellulose. The density, pore size distribution and wetting properties of the aerogel can be tuned by selecting the concentration of the nanocellulose dispersion before freeze-drying. The hydrophobic light- weight aerogels are almost instantly filled with the oil phase when selectively absorbing oil from water, with a capacity to absorb up to 45 times their own weight in oil. The oil can also be drained from the aerogel and the aerogel can then be reused for a second absorption cycle.
  •  
39.
  • Changqing, Ruan, et al. (författare)
  • A green and simple method for preparation of an efficient palladium adsorbent based on cysteine functionalized2,3-dialdehyde cellulose
  • 2016
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:4, s. 2627-2638
  • Tidskriftsartikel (refereegranskat)abstract
    • A green and efficient adsorbent for adsorption of palladium ions was prepared from 2,3-dialdehyde cellulose (DAC) originating from nanocellulose from the green algae Cladophora. The DAC was functionalized with cysteine via reductive amination in a convenient one-pot procedure to provide the adsorbent. The adsorption properties for adsorbing palladium(II) ions, including capacity, adsorption isotherm and kinetics, were studied. The successful reductive amination of cysteine with 2,3-dialdehyde cellulose was confirmed by FT-IR, elemental analysis and XPS. The adsorbent was characterized by SEM, XRD, gas adsorption and TGA. The adsorbent had a high adsorption capacity (130 mg palladium per gram adsorbent) and enabled fast adsorption of palladium(II) ions from solution (80 % of maximum capacity reached in 2 h). Adsorbent materials suitable for both filters (fibrous) and column matrixes (spherical particles) could be obtained in an efficient manner by controlling the degree of oxidation while producing the DAC material.
  •  
40.
  • Chen, Pan, et al. (författare)
  • Alternative hydrogen bond models of cellulose II and IIII based on molecular force-fields and density functional theory
  • 2015
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:3, s. 1485-1493
  • Tidskriftsartikel (refereegranskat)abstract
    • Alternative hydrogen-bond structures were found for cellulose II and IIII based on molecular dynamics simulations using four force fields and energy optimization based on density functional theory. All the modeling results were in support to the new hydrogen-bonding network. The revised structures of cellulose II and IIII differ with the fiber diffraction models mainly in the orientation of two hydroxyl groups, namely, OH2 and OH6 forming hydrogen-bond chains perpendicular to the cellulose molecule. In the alternative structures, the sense of hydrogen bond is inversed but little difference can be seen in hydrogen bond geometries. The preference of these alternative hydrogen bond structures comes from the local stabilization of hydroxyl groups with respect to the beta carbon. On the other hand when simulated fiber diffraction patterns were compared with experimental ones, the current structure of cellulose II with higher energy and the alternative structure of cellulose IIII with lower energy were in better agreement.
  •  
41.
  • Chen, Pan, et al. (författare)
  • I alpha to I beta mechano-conversion and amorphization in native cellulose simulated by crystal bending
  • 2018
  • Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X. ; 25:8, s. 4345-4355
  • Tidskriftsartikel (refereegranskat)abstract
    • The bending of rod-like native cellulose crystals with degree of polymerization 40 and 160 using molecular dynamics simulations resulted in a deformation-induced local amorphization at the kinking point and allomorphic interconversion between cellulose I alpha and I beta in the unbent segments. The transformation mechanism involves a longitudinal chain slippage of the hydrogen-bonded sheets by the length of one anhydroglucose residue ( 0.5 nm), which alters the chain stacking from the monotonic (I alpha) form to the alternating I beta one or vice versa. This mechanical deformation converts the I alpha form progressively to the I beta form, as has been experimentally observed for ultrasonication of microfibrils. I beta is also able to partially convert to I alpha-like organization but this conversion is only transitory. The qualitative agreement between the behavior of ultrasonicated microfibrils and in silico observed I alpha -> I beta conversion suggests that shear deformation and chain slippage under bending deformation is a general process when cellulose fibrils experience lateral mechanical stress.
  •  
42.
  • Chen, P., et al. (författare)
  • Quantifying the influence of dispersion interactions on the elastic properties of crystalline cellulose
  • 2021
  • Ingår i: Cellulose. - : Springer Nature. - 0969-0239 .- 1572-882X. ; 28:17, s. 10777-10786
  • Tidskriftsartikel (refereegranskat)abstract
    • Dispersion and electrostatic interactions both contribute significantly to the tight assembly of macromolecular chains within crystalline polysaccharides. Using dispersion-corrected density functional theory (DFT) calculation, we estimated the elastic tensor of the four crystalline cellulose allomorphs whose crystal structures that are hitherto available, namely, cellulose Iα, Iβ, II, IIII. Comparison between calculations with and without dispersion correction allows quantification of the exact contribution of dispersion to stiffness at molecular level.
  •  
43.
  • Choong, Ferdinand X., et al. (författare)
  • Stereochemical Identification of Glucans by a Donor-Acceptor-Donor Conjugated Pentamer Enables Multi-Carbohydrate Anatomical Mapping in Plant Tissues
  • 2019
  • Ingår i: Cellulose. - : Springer Netherlands. - 0969-0239 .- 1572-882X. ; 26:7, s. 4253-4264
  • Tidskriftsartikel (refereegranskat)abstract
    • Optotracing is a novel method for analytical imaging of carbohydrates in plant and microbial tissues. This optical method applies structure-responsive oligothiophenes as molecular fluorophores emitting unique optical signatures when bound to polysaccharides. Herein, we apply Carbotrace680, a short length anionic oligothiophene with a central heterocyclic benzodithiazole (BTD) motif, to probe for different glucans. The donor-acceptor-donor type electronic structure of Carbotrace680 provides improved spectral properties compared to oligothiophenes due to the possibility of intramolecular charge-transfer transition to the BTD motif. This enables differentiation of glucans based on the glycosidic linkage stereochemistry. Thus -configured starch is readily differentiated from -configured cellulose. The versatility of optotracing is demonstrated by dynamic monitoring of thermo-induced starch remodelling, shown in parallel by spectrophotometry and microscopy of starch granules. Imaging of Carbotrace680 bound to multiple glucans in plant tissues provided direct identification of their physical locations, revealing the spatial relationship between structural (cellulose) and storage (starch) glucans at sub-cellular scale. Our work forms the basis for the development of superior optotracers for sensitive detection of polysaccharides. Our non-destructive method for anatomical mapping of glucans in biomass will serve as an enabling technology for developments towards efficient use of plant-derived materials and biomass.
  •  
44.
  • Ciftci, Göksu Cinar, et al. (författare)
  • Tailoring of rheological properties and structural polydispersity effects in microfibrillated cellulose suspensions
  • 2020
  • Ingår i: Cellulose. - : Springer Science+Business Media B.V.. - 0969-0239 .- 1572-882X. ; 27:16, s. 9227-9241
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract: Industrial production of low-charge microfibrillated cellulose (MFC) typically results in wide fibril size distributions. This polydispersity influences viscosity, overall colloidal stability, and rheological properties of MFC suspensions and gels in aqueous systems. In this work, a systematic rheological analysis is performed for industrially prepared MFC and fractions of different size distributions. Gel formation and flow characteristics (e.g., shear-thinning) of each fraction are examined under neutral and acidic conditions and compared with the unfractionated MFC suspension. The effects of size, aspect ratio, and surface charge on the rheology of semi-dilute MFC suspensions are discussed. The results demonstrate that particle size and aspect ratio distribution control the viscoelasticity and shear-thinning properties of MFC suspensions. An increased fraction of small diameter nanofibrils, by ex situ addition of the fine particles with high aspect ratio or removal of the coarsest particles (with lower aspect ratio) by fractionation, significantly enhances the storage modulus and the yield stress of the complex mixture, compared to the properties of the coarser fractions. New insights are also reported on the tailoring of the rheology of highly polydisperse fibrillar mixtures, where the rheological contributions of each fraction are discussed. Graphic abstract: [Figure not available: see fulltext.].
  •  
45.
  • Colic, Miodrag, et al. (författare)
  • Cytocompatibility and immunomodulatory properties of wood based nanofibrillated cellulose
  • 2015
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 22:1, s. 763-778
  • Tidskriftsartikel (refereegranskat)abstract
    • Cellulose nanofibrils (CNFs), unique and promising natural materials have gained significant attention recently for biomedical applications, due to their special biomechanical characteristics, surface chemistry, good biocompatibility and low toxicity. However, their long bio-persistence within organisms may provoke chronic immune reactions and this aspect of CNFs has not been studied to date. Therefore, the aim of this work was to examine and compare the biocompatibility and immunomodulatory properties of CNFs in vitro. CNFs (diameters of 10-70nm; lengths of a few microns) were prepared from Norway spruce (Picea abies) by mechanical fibrillation and high pressure homogenisation. L929 cells, rat thymocytes or human peripheral blood mononuclear cells (PBMNCs) were cultivated with CNFs. None of the six concentrations of CNFs (31.25µg/ml – 1mg/ml) induced cytotoxicity and oxidative stress in the L929 cells, nor induced necrosis and apoptosis of the thymocytes and PBMNCs. Higher concentrations (250µg/ml – 1mg/ml) slightly inhibited the metabolic activities of the L929 cells as a consequence of inhibited proliferation. The same concentrations of CNFs suppressed the proliferation of PBMNCs to phytohemaglutinine, a T-cell mitogen, and the process was followed by down-regulation of interleukin-2 (IL-2) and interferon-γ (IFN-γ) production. The highest concentration of CNFs inhibited IL-17A but increased IL-10 and IL-6 production. The secretions of the inflammatory cytokines, IL-1β and the tumor necrosis factor-α (TNF-α) as well as Th2 cytokine (IL-4), remained unaltered. In conclusion, the results suggest that these CNFs are biocompatible, non-inflammatory and non-immunogenic nanomaterial. Higher concentrations seem to be tollerogenic to the immune system, a characteristic very desirable for implantable biomaterials.
  •  
46.
  • Colombani, A., et al. (författare)
  • In vitro synthesis of (1→3)-β-D-glucan (callose) and cellulose by detergent extracts of membranes from cell suspension cultures of hybrid aspen
  • 2004
  • Ingår i: Cellulose. - 0969-0239 .- 1572-882X. ; 11:3-4, s. 313-327
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this work was to optimize the conditions for in vitro synthesis of (1 --> 3)-beta-D-glucan (callose) and cellulose, using detergent extracts of membranes from hybrid aspen (Populus tremula x tremuloides) cells grown as suspension cultures. Callose was the only product synthesized when CHAPS extracts were used as a source of enzyme. The optimal reaction mixture for callose synthesis contained 100 mM Mops buffer pH 7.0, 1 mM UDP-glucose, 8 mM Ca2+, and 20 mM cellobiose. The use of digitonin to extract the membrane-bound proteins was required for cellulose synthesis. Yields as high as 50% of the total in vitro products were obtained when cells were harvested in the stationary phase of the growth curve, callose being the other product. The optimal mixture for cellulose synthesis consisted of 100 mM Mops buffer pH 7.0, 1 mM UDP-glucose, 1 mM Ca2+, 8 mM Mg2+, and 20 mM cellobiose. The in vitro beta-glucans were identified by hydrolysis of radioactive products, using specific enzymes. C-13-Nuclear magnetic resonance spectroscopy and transmission electron microscopy were also used for callose characterization. The (1-->3)-beta-D-glucan systematically had a microfibrillar morphology, but the size and organization of the microfibrils were affected by the nature of the detergent used for enzyme extraction. The discussion of the results is included in a short review of the field that also compares the data obtained with those available in the literature. The results presented show that the hybrid aspen is a promising model for in vitro studies on callose and cellulose synthesis.
  •  
47.
  • Correia, Viviane da Costa, et al. (författare)
  • Grinding process for the production of nanofibrillated cellulose based on unbleached and bleached bamboo organosolv pulp
  • 2016
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:5, s. 2971-2987
  • Tidskriftsartikel (refereegranskat)abstract
    • Nanofibrillated cellulose (NFC) is a type of nanomaterial based on renewable resources and produced by mechanical disintegration without chemicals. NFC is a potential reinforcing material with a high surface area and high aspect ratio, both of which increase reinforcement on the nanoscale. The raw materials used were unbleached and bleached bamboo organosolv pulp. Organosolv pulping is a cleaner process than other industrial methods (i.e. Kraft process), as it uses organic solvents during cooking and provides easy solvent recovery at the end of the process. The NFC was produced by treating unbleached and bleached bamboo organosolv pulps for 5, 10, 15 and 20 nanofibrillation cycles using the grinding method. Chemical, physical and mechanical tests were performed to determine the optimal condition for nanofibrillation. The delamination of the S2 layer of the fibers during nanofibrillation contributed to the partial removal of amorphous components (mainly lignin), which have low polarity and improved the adhesion of the fibers, particularly the unbleached cellulose. The transverse modulus of elasticity of the unbleached NFC was highest after 10 nanofibrillation cycles. Further treatment cycles decreased the modulus due to the mechanical degradation of the fibers. The unbleached NFC produced by 10 cycles have a greater transverse modulus of elasticity, the crystallite size showed increase with the nanofibrillation, and after 5 nanofibrillation cycles, no differences are observed in the morphology of the fibers.
  •  
48.
  • Cui, Sheng, et al. (författare)
  • Preparation of magnetic MnFe2O4-Cellulose aerogel composite and its kinetics and thermodynamics of Cu(II) adsorption
  • 2018
  • Ingår i: Cellulose. - : SPRINGER. - 0969-0239 .- 1572-882X. ; 25:1, s. 735-751
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a MnFe2O4-Cellulose magnetic composite aerogel (MnCA) with high adsorption capacity was fabricated by in situ incorporating MnFe2O4 to regenerated cellulose hydrogel matrix, followed by CO2 supercritical drying. A green synthetic strategy was performed by using renewable cellulose materials, environmentally benign cellulose solvents and facile synthetic conditions. The results showed that the obtained magnetic cellulose aerogel had a continuous and tiered three dimensional network with interconnected fibrils of about 30 nm in width, which was similar to those of cellulose aerogel prepared from NaOH/urea solution via CO2 supercritical drying. Meanwhile, they had high specific surface areas of 236-288 m(2)/g and total pore volume of 0.55-0.88 cm(3)/g. In addition, the hybrid aerogel showed superparamagnetism with maximum saturation magnetization reaching up to 18.53 emu/g. The magnetic nanocomposite aerogel could be used for biological and environmental applications. The adsorption test showed that MnCA had rapid adsorption rate and excellent adsorption ability of removing heavy metal ions in aqueous solution which could attain to 63.3 mg/g within 100 min. Moreover, all the composite aerogels exhibited good reusability and could be easily reused from the water after adsorption.
  •  
49.
  • Cunha, Ana Gisela, et al. (författare)
  • Topochemical acetylation of cellulose nanopaper structures for biocomposites : mechanisms for reduced water vapour sorption
  • 2014
  • Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 21:4, s. 2773-2787
  • Tidskriftsartikel (refereegranskat)abstract
    • Moisture sorption decreases dimensional stability and mechanical properties of polymer matrix biocomposites based on plant fibers. Cellulose nanofiber reinforcement may offer advantages in this respect. Here, wood-based nanofibrillated cellulose (NFC) and bacterial cellulose (BC) nanopaper structures, with different specific surface area (SSA), ranging from 0.03 to 173.3 m(2)/g, were topochemically acetylated and characterized by ATR-FTIR, XRD, solid-state CP/MAS C-13-NMR and moisture sorption studies. Polymer matrix nanocomposites based on NFC were also prepared as demonstrators. The surface degree of substitution (surface-DS) of the acetylated cellulose nanofibers is a key parameter, which increased with increasing SSA. Successful topochemical acetylation was confirmed and significantly reduced the moisture sorption in nanopaper structures, especially at RH = 53 %. BC nanopaper sorbed less moisture than the NFC counterpart, and mechanisms are discussed. Topochemical NFC nanopaper acetylation can be used to prepare moisture-stable nanocellulose biocomposites.
  •  
50.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 329
Typ av publikation
tidskriftsartikel (324)
forskningsöversikt (4)
konferensbidrag (1)
Typ av innehåll
refereegranskat (326)
övrigt vetenskapligt/konstnärligt (2)
populärvet., debatt m.m. (1)
Författare/redaktör
Wågberg, Lars (23)
Syverud, Kristin (21)
Larsson, Per Tomas (20)
Oksman, Kristiina (18)
Mathew, Aji P. (14)
Westman, Gunnar, 196 ... (12)
visa fler...
Ek, Monica (11)
Lindström, Tom (10)
Salmen, Lennart (9)
Naderi, Ali (9)
Stevanic Srndovic, J ... (8)
Chinga-Carrasco, Gar ... (8)
Nypelö, Tiina, 1982 (7)
Brännvall, Elisabet, ... (7)
Oksman, Kristiina, 1 ... (7)
Wågberg, Lars, 1956- (7)
Gatenholm, Paul, 195 ... (6)
Hasani, Merima, 1978 (6)
Bernin, Diana, 1979 (6)
Bergström, Lennart (6)
Strømme, Maria, 1970 ... (6)
Berglund, Lars A. (6)
Olsson, Ulf (6)
Wohlert, Jakob (6)
Zhou, Qi (6)
Pettersson, Torbjörn (5)
Theliander, Hans, 19 ... (5)
Nordstierna, Lars, 1 ... (5)
Fredriksson, Maria (5)
Aulin, Christian (5)
Kulachenko, Artem, 1 ... (5)
Kulachenko, Artem (5)
Rigdahl, Mikael, 195 ... (5)
Sevastyanova, Olena (5)
Köhnke, Tobias (5)
Skrifvars, Mikael (4)
Berglund, Linn (4)
Lindman, Björn (4)
Sundman, Ola (4)
Berglund, Lars, 1956 ... (4)
Xu, Chunlin (4)
Medronho, Bruno (4)
Kádár, Roland, 1982 (4)
Gentile, Luigi (4)
Larsson, Per A., 198 ... (4)
Lindh, Jonas, 1977- (4)
Wohlert, Jakob, 1976 ... (4)
Brelid, Harald, 1960 (4)
Larsson, Per A. (4)
Esteves, Claudia (4)
visa färre...
Lärosäte
Kungliga Tekniska Högskolan (136)
RISE (98)
Chalmers tekniska högskola (46)
Luleå tekniska universitet (38)
Lunds universitet (24)
Mittuniversitetet (23)
visa fler...
Uppsala universitet (14)
Stockholms universitet (13)
Linköpings universitet (9)
Umeå universitet (8)
Högskolan i Borås (5)
Karlstads universitet (5)
Karolinska Institutet (5)
Sveriges Lantbruksuniversitet (4)
Göteborgs universitet (3)
Högskolan i Skövde (3)
Malmö universitet (2)
Örebro universitet (1)
Linnéuniversitetet (1)
visa färre...
Språk
Engelska (329)
Forskningsämne (UKÄ/SCB)
Teknik (241)
Naturvetenskap (103)
Lantbruksvetenskap (14)
Medicin och hälsovetenskap (3)
Samhällsvetenskap (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy