| 1. |
- Abdelhamid, Hani Nasser, et al.
(författare)
-
CelloZIFPaper : Cellulose-ZIF hybrid paper for heavy metal removal and electrochemical sensing
- 2022
-
Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 446
-
Tidskriftsartikel (refereegranskat)abstract
- The processing of hierarchical porous zeolitic imidazolate frameworks (ZIF-8) into a cellulose paper using sheet former Rapid-Kothen (R.K.) is reported. The procedure is a promising route to overcome a significant bottleneck towards applying metal-organic frameworks (MOFs) in commercial products. ZIF-8 crystals were integrated into cellulose pulp (CP) or TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-oxidized cellulose nanofibrils (TOCNF) following an in-situ or ex-situ process; the materials were denoted as CelloZIFPaper_In Situ and CelloZIFPaper_Ex Situ, respectively. The materials were applied as adsorbents to remove heavy metals from water, with adsorption capacities of 66.2-354.0 mg/g. CelloZIFPaper can also be used as a stand-alone working electrode for the selective sensing of toxic heavy metals, for instance, lead ions (Pb2+), using electrochemical-based methods with a limit of detection (LOD) of 8 mu M. The electrochemical measurements may advance 'Lab-onCelloZIFPaper' technologies for label-free detection of heavy metal ions.
|
|
| 2. |
- Afewerki, Samson, et al.
(författare)
-
Combined Catalysis : A Powerful Strategy for Engineering Multifunctional Sustainable Lignin-Based Materials
- 2023
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 17:8, s. 7093-7108
-
Tidskriftsartikel (refereegranskat)abstract
- The production and engineering of sustainable materials through green chemistry will have a major role in our mission of transitioning to a more sustainable society. Here, combined catalysis, which is the integration of two or more catalytic cycles or activation modes, provides innovative chemical reactions and material properties efficiently, whereas the single catalytic cycle or activation mode alone fails in promoting a successful reaction. Polyphenolic lignin with its distinctive structural functions acts as an important template to create materials with versatile properties, such as being tough, antimicrobial, self-healing, adhesive, and environmentally adaptable. Sustainable lignin-based materials are generated by merging the catalytic cycle of the quinone-catechol redox reaction with free radical polymerization or oxidative decarboxylation reaction, which explores a wide range of metallic nanoparticles and metal ions as the catalysts. In this review, we present the recent work on engineering lignin-based multifunctional materials devised through combined catalysis. Despite the fruitful employment of this concept to material design and the fact that engineering has provided multifaceted materials able to solve a broad spectrum of challenges, we envision further exploration and expansion of this important concept in material science beyond the catalytic processes mentioned above. This could be accomplished by taking inspiration from organic synthesis where this concept has been successfully developed and implemented.
|
|
| 3. |
- Afewerki, Samson, 1985-, et al.
(författare)
-
Engineering an All-Biobased Solvent- and Styrene-Free Curable Resin
- 2023
-
Ingår i: ACS Polymers Au. - : American Chemical Society (ACS). - 2694-2453. ; 3:6, s. 447-456
-
Tidskriftsartikel (refereegranskat)abstract
- The sustainable production of polymers and materials derived from renewable feedstocks such as biomass is vital to addressing the current climate and environmental challenges. In particular, finding a replacement for current widely used curable resins containing undesired components with both health and environmental issues, such as bisphenol-A and styrene, is of great interest and vital for a sustainable society. In this work, we disclose the preparation and fabrication of an all-biobased curable resin. The devised resin consists of a polyester component based on fumaric acid, itaconic acid, 2,5-furandicarboxylic acid, 1,4-butanediol, and reactive diluents acting as both solvents and viscosity enhancers. Importantly, the complete process was performed solvent-free, thus promoting its industrial applications. The cured biobased resin demonstrates very good thermal properties (stable up to 415 °C), the ability to resist deformation based on the high Young’s modulus of ∼775 MPa, and chemical resistance based on the swelling index and gel content. We envision the disclosed biobased resin having tailorable properties suitable for industrial applications.
|
|
| 4. |
- Albers, Eva, 1966, et al.
(författare)
-
Influence of preservation methods on biochemical composition and downstream processing of cultivated Saccharina latissima biomass
- 2021
-
Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 55
-
Tidskriftsartikel (refereegranskat)abstract
- Saccharina latissima biomass cultivated along the Swedish west coast was subjected to four different scalable preservation methods after harvest; freezing, sun-drying, oven-drying and ensiling. Freeze-drying and freezing at -80 ?C were also included to provide dry and wet references. The effects of the different preservation methods on the composition of Saccharina biomass (on dry weight, DW, basis), and the recovery as well as properties of high-quality protein, alginate and biogas were evaluated. Sun-drying significantly reduced protein, alginate and fatty acid content of the seaweeds and thereby concentrated ash in the biomass compared to the other methods. Protein/amino acids and fatty acids were significantly concentrated in ensiled biomass, while mannitol and laminarin were reduced compared to the other biomasses. Oven-drying and -20 ?C freezing affected the composition the least, with lower ash content and alterations in some specific amino and fatty acids. Sun-drying and ensiling resulted in significantly lower protein solubility at high pH compared to the other biomasses which translated into the lowest total seaweed protein recovery using the pH-shift process. Highest protein yield was obtained with the freeze-dried reference. Ensiling lead to a significant decrease in the molecular weight of alginate, while sun-drying caused a negative effect on alginate by inducing a shift in the guluronic and mannuronic acids composition of alginate. Sun-drying gave the lowest methane yield in the anaerobic digestion experiments while freezing at -80 ?C gave the highest yield, closely followed by freezing at -20 ?C and ensiling. To conclude, preservation methods must be carefully chosen to protect the valuable component in Saccharina latissima, and to achieve an efficient downstream processing ultimately yielding high quality products as part of a seaweed biorefinery.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Albertsson, Ann-Christine, 1945-, et al.
(författare)
-
Increased biocompatibility by surface modification
- 2004
-
Ingår i: Abstracts of Papers of the American Chemical Society. - : American Chemical Society (ACS). - 0065-7727. ; 228, s. U508-U508
-
Tidskriftsartikel (populärvet., debatt m.m.)
|
|
| 8. |
- Albertsson, Ann-Christine, 1945-, et al.
(författare)
-
New matrices for controlled drug delivery.
- 2000
-
Ingår i: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY. - : American Chemical Society (ACS).
-
Konferensbidrag (refereegranskat)
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Albertsson, Ann-Christine, 1945-, et al.
(författare)
-
Surface modification of degradable polymers
- 2005
-
Ingår i: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY. - : American Chemical Society (ACS).
-
Konferensbidrag (refereegranskat)
|
|
| 13. |
|
|
| 14. |
- Albertsson, Ann-Christine, 1945-, et al.
(författare)
-
Vedrester blir förnybar råvara
- 2009
-
Ingår i: Miljöforskning. - Stockholm : Formas. - 1650-4925. ; :5, s. 20-21
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Cellulosa används sedan länge i många produkter. Än så länge gäller det främst inom trävaru-, pappers- och massaindustrin. Men veden innehåller även andra ämnen, som idag mest ses som onödiga restprodukter. Aktuell forskning vid KTH visar att sådana produkter i framtiden kan bli användbara i till exempel förpackningar, läkemedelsindustri och jordbruk.
|
|
| 15. |
- Albertsson, Ann-Christine, et al.
(författare)
-
Wood hydrolysates : From fractions to products
- 2015
-
Ingår i: Abstracts of Papers of the American Chemical Society. - : AMER CHEMICAL SOC. - 0065-7727. ; 249
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 16. |
- Alvarado Ávila, María Isabel, et al.
(författare)
-
Cellulose as sacrificial agents for enhanced photoactivated hydrogen production
- 2023
-
Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry (RSC). - 2398-4902. ; 7:8, s. 1981-1991
-
Tidskriftsartikel (refereegranskat)abstract
- The search for new energy sources together with the need to control greenhouse gas emissions has led to continued interest in low-emitting renewable energy technologies. In this context, water splitting for hydrogen production is a reasonable alternative to replace fossil fuels due to its high energy density producing only water during combustion. Cellulose is abundant in nature and as residuals from human activity, and therefore a natural, ecological, and carbon-neutral source for hydrogen production. In the present work, we propose a sustainable method for hydrogen production using sunlight and cellulose as sacrificial agents during the photocatalytic water splitting process. Platinum (Pt) catalyst activates hydrogen production, and parameters such as pH of the system, cellulose concentration, and Pt loading were studied. Using different biomasses, we found that the presence of hemicellulose and xyloglucan as part of the molecular composition considerably increased the H-2 production rate from 36 mu mol L-1 in one hour for rapeseed cellulose to 167.44 mu mol L-1 for acid-treated cellulose isolated from Ulva fenestrata algae. Carboxymethylation and TEMPO-oxidation of cellulosic biomass both led to more stable suspensions with higher rates of H-2 production close to 225 mu mol L-1, which was associated with their water solubility properties. The results suggest that cellulosic biomass can be an attractive alternative as a sacrificial agent for the photocatalytic splitting of water for H-2 production.
|
|
| 17. |
- 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.
|
|
| 18. |
- Choong, Ferdinand X., et al.
(författare)
-
Stereochemical identification of glucans by oligothiophenes enables cellulose anatomical mapping in plant tissues
- 2018
-
Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Efficient use of plant-derived materials requires enabling technologies for non-disruptive composition analysis. The ability to identify and spatially locate polysaccharides in native plant tissues is difficult but essential. Here, we develop an optical method for cellulose identification using the structure-responsive, heptameric oligothiophene h-FTAA as molecular fluorophore. Spectrophotometric analysis of h-FTAA interacting with closely related glucans revealed an exceptional specificity for beta-linked glucans. This optical, non-disruptive method for stereochemical differentiation of glycosidic linkages was next used for in situ composition analysis in plants. Multi-laser/multi-detector analysis developed herein revealed spatial localization of cellulose and structural cell wall features such as plasmodesmata and perforated sieve plates of the phloem. Simultaneous imaging of intrinsically fluorescent components revealed the spatial relationship between cell walls and other organelles, such as chloroplasts and lignified annular thickenings of the trachea, with precision at the sub-cellular scale. Our non-destructive method for cellulose identification lays the foundation for the emergence of anatomical maps of the chemical constituents in plant tissues. This rapid and versatile method will likely benefit the plant science research fields and may serve the biorefinery industry as reporter for feedstock optimization as well as in-line monitoring of cellulose reactions during standard operations.
|
|
| 19. |
|
|
| 20. |
- Edlund, Ulrica, 1972-, et al.
(författare)
-
Admicellar Polymerization Coating of CNF Enhances Integration in Degradable Nanocomposites
- 2019
-
Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 20:2, s. 684-692
-
Tidskriftsartikel (refereegranskat)abstract
- A water-based one-pot synthesis strategy for converting cellulose nanofibrils (CNF) into a hydrophobic and processable biopolymer grade is devised. CNF was chemically modified through admicellar polymerization, producing fibrils coated with fatty acrylate polymers. The proposed modification targets a change in the interfibrillar interactions and improved CNF compatibility with a degradable plastic composite matrix, poly(butylene adipate-co-terephthalate), PBAT in composites prepared by melt extrusion. CNF had a clear reinforcing effect on PBAT, increasing Young's modulus by at least 35% and 169% at 5 and 20% (w/w) CNF content, respectively. However, unmodified CNF showed aggregation, poor adhesion in the matrix, and severely impaired the ductility of PBAT. CNF modified by admicellar polymerization was homogeneously dispersed in the PBT matrix and showed significantly better preservation of the elongation properties compared to unmodified CNF, especially at 5% (w/w) addition level.
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Edlund, Ulrica, 1972-, et al.
(författare)
-
Covalent VEGF protein immobilization on resorbable polymeric surfaces
- 2011
-
Ingår i: Polymers for Advanced Technologies. - : Wiley. - 1042-7147 .- 1099-1581. ; 22:1, s. 166-171
-
Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor (VEGF) type protein, a potent angiogenic effector molecule, was successfully covalently immobilized onto the surfaces of the resorbable polymers poly(L-lactic acid) (PLLA) and poly(epsilon-caprolactone) through a three-step strategy. The surfaces were first covalently grafted with poly(acrylic acid) using non-destructive and solvent-free vapor-phase grafting. A diamine spacer was coupled to the carboxylic acid pendant groups on the graft chains using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride/N-hydroxysuccinimide chemistry and VEGF was finally covalently attached to the amine linkers. The chemistry and topography of the modified substrates were quantitatively and qualitatively verified with X-ray photoelectron spectroscopy, attenuated total reflectance-Fourier transform infrared spectrometry, UV-VIS, scanning electron microscopy, and enzyme-linked immunosorbent assay
|
|
| 24. |
|
|
| 25. |
- Edlund, Ulrica, 1972-, et al.
(författare)
-
Macroinitiator Halide Effects in Galactoglucomannan-Mediated Single Electron Transfer-Living Radical Polymerization
- 2011
-
Ingår i: Journal of Polymer Science Part A. - : Wiley. - 0887-624X .- 1099-0518. ; 49:19, s. 4139-4145
-
Tidskriftsartikel (refereegranskat)abstract
- Chloro (Cl)- and bromo (Br)-functionalized macroinitiators were successfully prepared from the softwood hemicellulose O-acetylated galactoglucomannan (AcGGM) and then explored and evaluated with respect to their ability and efficiency of initiating single electron transfer-living radical polymerization (SET-LRP). Both halogenated species effectively initiate SET-LRP of an acrylate and a methacrylate monomer, respectively, yielding brushlike AcGGM graft copolymers, where the molecular weights are accurately controlled via the monomer:macroinitiator ratio and polymerization time over a broad range: from oligomeric to ultrahigh. The nature of the halogen does not influence the kinetics of polymerization strongly, however, for acrylate graft polymerization, AcGGM-Cl gives a somewhat higher rate constant of propagation, while methacrylate grafting proceeds slightly faster when the initiating species is AcGGM-Br. For both monomers, the macroinitiator efficiency is superior in the case of AcGGM-Br.
|
|
| 26. |
- Galkin, Maxim V., et al.
(författare)
-
Sustainable sources need reliable standards
- 2017
-
Ingår i: Faraday discussions. - : ROYAL SOC CHEMISTRY. - 1359-6640 .- 1364-5498. ; 202, s. 281-301
-
Tidskriftsartikel (refereegranskat)abstract
- This review discusses the challenges within the research area of modern biomass fractionation and valorization. The current pulping industry focuses on pulp production and the resulting cellulose fiber. Hemicellulose and lignin are handled as low value streams for process heat and the regeneration of process chemicals. The paper and pulp industry have therefore developed analytical techniques to evaluate the cellulose fiber, while the other fractions are given a low priority. In a strive to also use the hemicellulose and lignin fractions of lignocellulosic biomass, moving towards a biorefining concept, there are severe shortcomings with the current pulping techniques and also in the analysis of the biomass. Lately, new fractionation techniques have emerged which valorize a larger extent of the lignocellulosic biomass. This progress has disclosed the shortcomings in the analysis of mainly the hemicellulose and lignin structure and properties. To move the research field forward, analytical tools for both the raw material, targeting all the wood components, and the generated fractions, as well as standardized methods for evaluating and reporting yields are desired. At the end of this review, a discourse on how such standardizations can be implemented is given.
|
|
| 27. |
- Gamiz Gonzalez, Maria Amparo, et al.
(författare)
-
Synthesis of highly swellable hydrogels of water-soluble carboxymethyl chitosan and poly(ethylene glycol)
- 2017
-
Ingår i: Polymer international. - : WILEY. - 0959-8103 .- 1097-0126. ; 66:11, s. 1624-1632
-
Tidskriftsartikel (refereegranskat)abstract
- Highly swellable hydrogels were produced by crosslinking of high molecular weight carboxymethylated chitosan (CmCHT) with poly(ethylene glycol) (PEG) oligomers. The hydrogel swelling capacity could be controlled via the crosslinking density and ranged from 900% to 5600%. The hydrogels showed good homogeneity with a high interconnected porosity in the swollen state and with nanodomains rich in CmCHT and others rich in PEG diglycidyl ether. Oscillatory frequency sweep analysis showed a storage modulus of 27kPa for the hydrogel with the highest crosslinking density, which together with the exhibited enzyme degradability with lysozyme at 59days indicate that these hydrogels have potential use in delivery systems or soft tissue regeneration.
|
|
| 28. |
- Georgouvelas, Dimitrios, et al.
(författare)
-
All-cellulose functional membranes for water treatment : Adsorption of metal ions and catalytic decolorization of dyes
- 2021
-
Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 264
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we present a facile, one-step method for the manufacturing of all-cellulose, layered membranes containing cellulose nanocrystals (CNC), TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidized cellulose nanofibers (TO-CNF), or zwitterionic polymer grafted cellulose nanocrystals (CNC-gPCysMA) as functional entities in combination with cellulose fibers and commercial grade microfibrillated cellulose. The presence of active sites such as hydroxyl, carbonyl, thioethers, and amines, gave the membranes high adsorption capacities for the metal ions Au (III), Co (II), and Fe (III), as well as the cationic organic dye methylene blue (MB). Furthermore, the membranes served as excellent metal-free catalysts for the decolorization of dyes via hydrogenation. A 3-fold increase of the hydrogenation efficiency for cationic dyes such as rhodamine B (RhB) and methylene blue was obtained in the presence of membranes compared to NaBH4 alone. Water-based processing, the abundance of the component materials, and the multifunctional characteristics of the membranes ensure their potential as excellent candidates for water purification systems.
|
|
| 29. |
- Georgouvelas, Dimitrios, et al.
(författare)
-
In situ modified nanocellulose/alginate hydrogel composite beads for purifying mining effluents
- 2023
-
Ingår i: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 5:21, s. 5892-5899
-
Tidskriftsartikel (refereegranskat)abstract
- Biobased adsorbents and membranes offer advantages related to resource efficiency, safety, and fast kinetics but have challenges related to their reusability and water flux. Nanocellulose/alginate composite hydrogel beads were successfully prepared with a diameter of about 3-4 mm and porosity as high as 99%. The beads were further modified with in situ TEMPO-mediated oxidation to functionalize the hydroxyl groups of cellulose and facilitate the removal of cationic pollutants from aqueous samples at low pressure, driven by electrostatic interactions. The increased number of carboxyl groups in the bead matrix improved the removal efficiency of the adsorbent without compromising the water throughput rate; being as high as 17 000 L h(-1) m(-2) bar(-1). The absorptivity of the beads was evaluated with UV-vis for the removal of the dye Methylene Blue (91% removal) from spiked water and energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) elemental analyses for the removal of Cd2+ from industrial mining effluents. The modified beads showed a 3-fold increase in ion adsorption and pose as excellent candidates for the manufacturing of three-dimensional (3-D) column filters for large-volume, high flux water treatment under atmospheric pressure.
|
|
| 30. |
- Georgouvelas, Dimitrios, et al.
(författare)
-
Residual Lignin and Zwitterionic Polymer Grafts on Cellulose Nanocrystals for Antifouling and Antibacterial Applications
- 2020
-
Ingår i: ACS APPLIED POLYMER MATERIALS. - : American Chemical Society (ACS). - 2637-6105. ; 2:8, s. 3060-3071
-
Tidskriftsartikel (refereegranskat)abstract
- Hybrid materials from nanocellulose, lignin, and surface- grafted zwitterionic poly(sulfobetaine methacrylate) (PSBMA) chains are prepared to attain antifouling bio-based nanomaterials with enhanced antibacterial performance. The grafting of PSBMA from both cellulose and lignocellulose nanocrystals (CNC and LCNC, respectively) is attempted; however, the materials' analysis with FTIR, XPS, and solid-state C-13 NMR reveals that the grafting on LCNC is negligible. Antifouling and antibacterial performances of CNC and LCNC, as well as PSBMA-grafted CNC, are evaluated by using quartz crystal microbalance with dissipation monitoring, confocal microscopy, and the agar diffusion method using bovine serum albumin and E. coli ACTT 8937 as protein model and bacterial model, respectively. The results demonstrate that the grafting of CNC with PSBMA improves the antifouling and antibacterial activity of the material compared to pristine CNC and LCNC.
|
|
| 31. |
|
|
| 32. |
- Ibn Yaich, Anas, 1986-, et al.
(författare)
-
Transfer of Biomatrix/Wood Cell Interactions to Hemicellulose-Based Materials to Control Water Interaction
- 2017
-
Ingår i: Chemical Reviews. - : AMER CHEMICAL SOC. - 0009-2665 .- 1520-6890. ; 117:12, s. 8177-8207
-
Forskningsöversikt (refereegranskat)abstract
- The family of hemicelluloses stands out as a very promising natural resource that can be utilized as a biobased materials feedstock. An in-depth understanding of the hemicellulose inherent structural and property features as well as the structure property relationships induced by the specific supramolecular hierarchical organization of lignocellulosic biopolymers will be a key enabling technology in the emerging biorefinery sector. This Review aims to give a perspective on these issues and demonstrate how the transfer of molecular wood cell interactions into hemicellulose-based materials may offer new design principles for material formulations.
|
|
| 33. |
- Imam, Mohammad, et al.
(författare)
-
Dendronized Supramolecular Polymers Self-Assembled from Dendritic Ionic Liquids
- 2009
-
Ingår i: Journal of Polymer Science Part A. - : Wiley-Blackwell. - 0887-624X .- 1099-0518. ; 47:16, s. 4165-4193
-
Tidskriftsartikel (refereegranskat)abstract
- The synthesis, structural, and retrostructural analysis of a library of self-assembling dendrons containing triethyl and tripropyl ammonium, pyridinium and 3-methylimidazolium chloride, tetrafluoroborate, and hexafluorophosphate at their apex are reported. These dendritic ionic liquids self-assemble into supramolecular columns or spheres which self-organize into 21) hexagonal or rectangular and 31) cubic or tetragonal liquid crystalline and crystalline lattices. Structural analysis by X-ray diffraction experiments demonstrated the self-assembly of supramolecular dendrimers containing columnar and spherical nanoscale ionic liquid reactors segregated in their core. Both in the supramolecular columns and spheres the noncovalent interactions mediated by the ionic liquid provide a supramolecular polymer and therefore, these assemblies represent a new class of dendronized supramolecular polymers.
|
|
| 34. |
- Karkkainen, Elina, et al.
(författare)
-
Optotracing for live selective fluorescence-based detection of Candida albicans biofilms
- 2022
-
Ingår i: Frontiers in Cellular and Infection Microbiology. - : Frontiers Media SA. - 2235-2988. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Candida albicans is the most common fungal pathogen in humans, implicated in hospital-acquired infections, secondary infections in human immunodeficiency virus (HIV) patients, and is a significant contributor to the global antimicrobial resistance (AMR) burden. Early detection of this pathogen is needed to guide preventative strategies and the selection and development of therapeutic treatments. Fungal biofilms are a unique heterogeneous mix of cell types, extracellular carbohydrates and amyloid aggregates. Perhaps due to the dominance of carbohydrates in fungi, to date, few specific methods are available for the detection of fungal biofilms. Here we present a new optotracing-based method for the detection and analysis of yeast and biofilms based on C. albicans SC5314 as a model. Using commercial extracts of cell wall carbohydrates, we showed the capability of the optotracer EbbaBiolight 680 for detecting chitin and beta-glucans. The sensitivity of this tracer to these carbohydrates in their native environment within fungal cells enabled the visualization of both yeast and hyphal forms of the microbe. Analysis of optotracer fluorescence by confocal laser scanning microscopy revealed extensive staining of fungi cell walls as well as the presence of intracellular amyloid aggregates within a subpopulation of cells within the biofilm. Further analysis of the photophysical properties of bound tracers by spectroscopy and spectral imaging revealed polymorphisms between amyloid aggregates within yeast and hyphal cells and enabled their differentiation. With exceptional spatial and temporal resolution, this assay adds a new technique that facilitates future understanding of fungal biofilms and their formation, and enables direct, unbiased diagnostics of these medically relevant biofilms, as well as the development of antifungal strategies.
|
|
| 35. |
- Kinnby, Alexandra, et al.
(författare)
-
Ocean acidification reduces thallus strength in a non-calcifying foundation seaweed
- 2023
-
Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 33:18, s. 941-942
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change is causing unprecedented changes in terrestrial and aquatic ecosystems through the emission of greenhouse gases, including carbon dioxide (CO2). Approximately 30% of CO2 is taken up by the ocean (‘ocean acidification’, OA)1, which has profound effects on foundation seaweed species. Negative physical effects on calcifying algae are clear2, but studies on habitat-forming fleshy seaweeds have mainly focused on growth and less on thallus strength3,4. We exposed the habitat-forming brown seaweed Fucus vesiculosus to OA corresponding to projected climate change effects for the year 2100, and observed reduced apical thallus strength and greater loss of exposed individuals in the field. The tissue contained less calcium and magnesium, both of which are important for creating structural alginate matrices. Scanning electron microscopy (SEM) revealed tissue voids in the OA samples that were not present in seaweeds grown under ambient pCO2. We conclude that under OA, weakened F. vesiculosus will be at a significantly higher risk of physical damage and detachment.
|
|
| 36. |
- Krivánková, Nikola, et al.
(författare)
-
Copper-mediated synthesis of temperature-responsive poly(N-acryloyl glycinamide) polymers : a step towards greener and simple polymerisation
- 2023
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 13:42, s. 29099-29108
-
Tidskriftsartikel (refereegranskat)abstract
- Stimuli-responsive materials with reversible supramolecular networks controlled by a change in temperature are of interest in medicine, biomedicine and analytical chemistry. For these materials to become more impactful, the development of greener synthetic practices with more sustainable solvents, lower energy consumption and a reduction in metallic catalysts is needed. In this work, we investigate the polymerisation of N-acryloyl glycinamide monomer by single-electron transfer reversible-deactivation radical polymerisation and its effect on the cloud point of the resulting PNAGA polymers. We accomplished 80% conversion within 5 min in water media using a copper wire catalyst. The material exhibited a sharp upper critical solution temperature (UCST) phase transition (10–80% transition within 6 K). These results indicate that UCST-exhibiting PNAGA can be synthesized at ambient temperatures and under non-inert conditions, eliminating the cost- and energy-consuming deoxygenation step. The choice of copper wire as the catalyst allows the possibility of catalyst recycling. Furthermore, we show that the reaction is feasible in a simple vial which would facilitate upscaling.
|
|
| 37. |
- Le Normand, Myriam, et al.
(författare)
-
SPRUCE BARK HEMICELLULOSES AND PECTINS : EXTRACTION AND CHARACTERIZATION
- 2011
-
Ingår i: 16TH INTERNATIONAL SYMPOSIUM ON WOOD, FIBER AND PULPING CHEMISTRY, PROCEEDINGS, VOLS I & II. - : CHINA LIGHT INDUSTRY PRESS. ; , s. 103-106
-
Konferensbidrag (refereegranskat)abstract
- In industrial spruce bark, up to 20 % of the dry mass consists of non-cellulosic polysaccharides. These polysaccharides can easily be extracted with pressurized hot water and have a large potential as a starting polymeric biomass for functional materials development. In this study, spruce bark was collected directly after the debarking process. The different steps of extraction were performed in an Accelerated Solvent Extractor (ASE). Bark was first extracted with acetone at 100 degrees C to remove extractives. Spruce bark polysaccharides could then be extracted with pressurized water at 100-460 degrees C with the highest yield at 140 degrees C. They were mainly composed of glucose, arabinose and galacturonic acid units which revealed the presence of pectic substances, starch and arabinose-rich hemicelluloses, e.g. arabinans. Molecular weight estimations showed the presence of rather large polysaccharides with a Mw varying between 10 to 30 kDa, depending of the extraction conditions.
|
|
| 38. |
- Maleki, Laleh, et al.
(författare)
-
Synthesis of full interpenetrating hemicellulose hydrogel networks
- 2017
-
Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 170, s. 254-263
-
Tidskriftsartikel (refereegranskat)abstract
- Two methods with different cross-linking mechanisms for designing hemicellulose-based full interpenetrating polymer networks (IPNs) were developed through the sequential synthesis of full IPNs from O-acetyl-galactoglucomannan (AcGGM) utilizing free-radical polymerization and a thiol-ene click reaction. A faster swelling rate was observed for all IPN formulations compared with the single-network gels. The highly porous structure of the IPNs with small interconnected pores was verified using scanning electron microscopy. A rheological analysis revealed that the AcGGM IPNs fabricated by the free-radical polymerization of acrylamide and N-N'-methylenebisacrylamide (cross-linker) had shear storage modulus (G') values approximately 5 and 2.5 times higher than that of the corresponding precursor single networks of AcGGM. IPNs achieved through thiol-ene reactions between thiolated AcGGM and polyethylene glycol diacrylate had G' values 35-40 times higher than the single-network reference hydrogels.
|
|
| 39. |
- Mietner, J. Benedikt, et al.
(författare)
-
3D printing of a bio-based ink made of cross-linked cellulose nanofibrils with various metal cations
- 2021
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, we present an approach to cross-link cellulose nanofibrils (CNFs) with various metallic cations (Fe3+, Al3+, Ca2+, and Mg2+) to produce inks suitable for three-dimensional (3D) printing application. The printability of each hydrogel ink was evaluated, and several parameters such as the optimal ratio of Mn+:TOCNF:H2O were discussed. CNF suspensions were produced by mechanical disintegration of cellulose pulp with a microfluidizer and then oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Finally, metal cations were introduced to the deprotonated TEMPO-oxidized CNF (TOCNF) suspension to cross-link the nanofibrils and form the corresponding hydrogels. The performances of each gel-ink were evaluated by rheologica I measurements and 3D printing. Only the gels incorporated with divalent cations Ca2+ and Mg2+ were suitable for 3D printing. The 3D printed structures were freeze-dried and characterized with Fourier transform infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). The better interaction of the TOCNFs with the divalent metallic cations in terms of printability, the viscoelastic properties of the inks, and the variation trends owing to various metal cations and ratios are discussed.
|
|
| 40. |
- Navarro, J. R. G., et al.
(författare)
-
Surface-Initiated Controlled Radical Polymerization Approach to in Situ Cross-Link Cellulose Nanofibrils with Inorganic Nanoparticles
- 2020
-
Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 21:5, s. 1952-1961
-
Tidskriftsartikel (refereegranskat)abstract
- This paper investigates a strategy to convert hydrophilic cellulose nanofibrils (CNF) into a hydrophobic highly cross-linked network made of cellulose nanofibrils and inorganic nanoparticles. First, the cellulose nanofibrils were chemically modified through an esterification reaction to produce a nanocellulose-based macroinitiator. Barium titanate (BaTiO3, BTO) nanoparticles were surface-modified by introducing a specific monomer on their outer-shell surface. Finally, we studied the ability of the nanocellulose-based macroinitiator to initiate a single electron transfer living radical polymerization of stearyl acrylate (SA) in the presence of the surface-modified nanoparticles. The BTO nanoparticles will transfer new properties to the nanocellulose network and act as a cross-linking agent between the nanocellulose fibrils, while the monomer (SA) directly influences the hydrophilic-lipophilic balance. The pristine CNF and the nanoparticle cross-linked CNF are characterized by FTIR, SEM, and solid-state 13C NMR. Rheological and dynamic mechanical analyses revealed a high dregee of cross-linking.
|
|
| 41. |
- Ogonowski, Martin, et al.
(författare)
-
Multi-level toxicity assessment of engineered cellulose nanofibrils in Daphnia magna
- 2018
-
Ingår i: Nanotoxicology. - : Taylor & Francis. - 1743-5390 .- 1743-5404. ; 12:6, s. 509-521
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanofibril (CNF)-based materials are increasingly used in industrial and commercial applications. However, the impacts of CNF on aquatic life are poorly understood, and there are concerns regarding their potential toxicity. Using a combination of standard ecotoxicological tests and feeding experiments, we assessed the effects of CNF exposure (0.206-20.6 mg/L) on the feeding (food uptake and gut residence time) and life-history traits (growth and reproduction) in the cladoceran Daphnia magna. No mortality was observed in a 48 h acute exposure at 2060 mg/L. Moreover, a 21-day exposure at low food and moderate CNF levels induced a stimulatory effect on growth, likely driven by increased filtration efficiency, and, possibly, partial assimilation of the CNF by the animals. However, at low food levels and the highest CNF concentrations, growth and reproduction were negatively affected. These responses were linked to caloric restriction caused by dilution of the food source, but not an obstruction of the alimentary canal. Finally, no apparent translocation of CNF past the alimentary canal was detected. We conclude that CNF displays a low toxic potential to filter-feeding organisms and the expected environmental risks are low.
|
|
| 42. |
- Olsson, Joakim, 1988, et al.
(författare)
-
Cultivation conditions affect the monosaccharide composition in Ulva fenestrata
- 2020
-
Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 32, s. 3255-3263
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years, the interest in using seaweed for the sustainable production of commodities has been increasing as seaweeds contain many potentially worthwhile compounds. Thus, the extraction and refining processes of interesting compounds from seaweeds is a hot research topic but has been found to have problems with profitability for novel applications. To increase the economic potential of refining seaweed biomass, the content of the compounds of interest should be maximized, which can potentially be achieved through optimization of cultivation conditions. In this study, we studied how the monosaccharide composition of the green seaweed species Ulva fenestrata is influenced by the abiotic factors; irradiance, temperature, nitrate, phosphate, and pCO(2). It was evident that lower nitrate concentration and cultivation at elevated temperature increased monosaccharide contents. A 70% increase in iduronic acid and a 26% increase in rhamnose content were seen under elevated irradiance and temperature conditions, though the absolute differences in monosaccharide concentration were small. Irradiance and nitrate impacted the ratio between iduronic and rhamnose, which is an indicator of the ulvan structure. These results could potentially be utilized to coax the ulvan towards specific bioactivities, and thus have a considerable impact on a potential biorefinery centered around Ulva.
|
|
| 43. |
|
|
| 44. |
|
|
| 45. |
- Persson, Johanna, et al.
(författare)
-
Modification of birch xylan by lactide-grafting
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 27:3, s. 518-524
-
Tidskriftsartikel (refereegranskat)abstract
- 4-O-methylglucuronoxylan, isolated by ultrafiltration from a birch kraft cooking liquor, was delignified and subsequently modified by grafting lactide-chains onto the hydroxyl groups via ring opening polymerization with L-lactide. The structures and average molar masses of the lactide-grafted xylan polymers were characterised by NMR and SEC respectively. By varying the lactide-to-xylan feed ratio, graft polymers with different graft levels were synthesized. The degree of substitution of the hydroxyls in the xylan back-bone ranged from 0.7 to 1.7 with lactide side-chains having an average length of 1.2 to 2.5 lactide units. The side-chain length and degree of substitution influenced the hydrophobicity, thermal properties and tensile strength properties. A glass transition could be detected for lactide-grafted xylan polymers with lactide chains longer than 1.8 lactide units. Solution-cast thin films prepared from lactide-grafted xylans exhibited strong tensile strength and high modulus with decreasing strength and increasing elongation at break as the lactide chain length was increased.
|
|
| 46. |
- Rostami, Jowan
(författare)
-
Functional Low-Density Materials from Cellulose Fibers and Fibrils
- 2024
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cellulose-based aerogels are emerging bio-based materials for a range of applications in the quest toward a circular and carbon-neutral society. Owing to their lightweight nature, high porosity, high specific surface area, biocompatibility, and biodegradability, cellulose aerogels are suitable for packaging, insulation, wound care products, hygiene products, and water purification. However, their commercial use is hampered by complicated time- and energy-consuming fabrication processes. Hence, industrially relevant processes with upscaling opportunities need to be developed for cellulose-based aerogels to reach their full potential. This thesis explores different scalable and simple methods for preparing and designing highly porous aerogels with high wet integrity using cellulose-rich fibers and cellulose nanofibrils (CNFs). As wet integrity is crucial for specific applications and enables further functionalization of the aerogels using water-based chemistry, different methods were developed to achieve wet integrity without complicated crosslinking procedures. The effects of the raw materials and processing methods on the final material properties were also carefully studied to optimize the performance for the targeted applications. Moreover, the role of the network-forming ability of CNFs in the development of functional materials with structural integrity was explored by incorporating small amounts of CNFs in aerogel systems based on macroscopic cellulose-rich fibers and nanosized metal-organic frameworks. Finally, the potential of the different developed cellulose-based or cellulose-reinforced aerogels with high wet integrity was demonstrated in applications for which the aerogels’ structural integrity and physical and mechanical properties are highly advantageous, such as biomedical applications, gas storage and separation, flame retardancy, and hygiene products. As demonstrated in this thesis, these functional aerogel materials could be a bio-based alternative for today’s fossil-based materials.
|
|
| 47. |
- Rostami, Jowan, et al.
(författare)
-
Zwitterionic acetylated cellulose nanofibrils
- 2019
-
Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 24:17
-
Tidskriftsartikel (refereegranskat)abstract
- A strategy is devised to synthesize zwitterionic acetylated cellulose nanofibrils (CNF). The strategy included acetylation, periodate oxidation, Schiff base reaction, borohydride reduction, and a quaternary ammonium reaction. Acetylation was performed in glacial acetic acid with a short reaction time of 90 min, yielding, on average, mono-acetylated CNF with hydroxyl groups available for further modification. The products from each step were characterized by FTIR spectroscopy, ζ-potential, SEM-EDS, AFM, and titration to track and verify the structural changes along the sequential modification route.
|
|
| 48. |
- Ryberg, Y. Z., et al.
(författare)
-
Renewable barrier films from wood hydrolysates
- 2012
-
Ingår i: NWBC 2012 - 4th Nordic Wood Biorefinery Conference. - : VTT Technical Research Centre of Finland. ; , s. 382-383
-
Konferensbidrag (refereegranskat)abstract
- To study, develop and enable industrially feasible utilization of wood hydrolysates (WHs), a Hansen’s Solubility Parameter (HSP) model was developed. The model aims to design formulations based on WH for efficient oxygen barrier films and coatings. Analyses such as Position Annihilation Lifetime Spectroscopy (PALS) and oxygen permeability (OP) tests strongly supported the model.
|
|
| 49. |
- Saadatmand, Soheil, et al.
(författare)
-
Design of new bioresource packaging from wood hydrolysates
- 2012
-
Ingår i: NWBC 2012 - 4th Nordic Wood Biorefinery Conference. - : VTT Technical Research Centre of Finland. ; , s. 378-379
-
Konferensbidrag (refereegranskat)abstract
- Two types of hemicellulose-based spruce wood hydrolysates were upgraded through ultrafiltration and diafiltration to separate the higher molecular weight fraction of the wood hydrolysates. Upgraded wood hydrolysates were thereafter used, together with different co-components to produce films with very good oxygen barrier properties and acceptable mechanical properties.
|
|
| 50. |
- Schmidt, Alina E. M., et al.
(författare)
-
Defibrillated Lignocellulose Recovery Guided by Plant Chemistry and Anatomy – A Pioneering Study with Lupinus angustifolius
- 2024
-
Ingår i: Advanced Sustainable Systems. - : Wiley. - 2366-7486 .- 2366-7486.
-
Tidskriftsartikel (refereegranskat)abstract
- The strive toward sustainability increases the demand for bio-based material production, forcing expansion of the biorefinery feedstock supply from forest wood to non-woody materials such as agricultural residues. As a model organism for legume crops, the aptness of agricultural lupins as a lignocellulose feedstock is investigated. Principle chemical analysis combined with optotracing, in which the fluorescent tracer molecule Carbotrace 680 generates a visual map of the native tissues’ lignocellulose anatomy at sub-cellular resolution, enables informed design of a mild recovery process. A streamlined conversion approach is then designed, yielding lignin-containing microfibrillated cellulose. By monitoring defibrillation and delignification throughout the extraction process, the use of optotracing for non-destructive fiber analytics at unprecedented details across all hierarchical structures of lignocellulosic materials is demonstrated. This crop valorization is a prime illustration of a holistic use of lupin biomass, with seeds serving as plant-based food sources, and other parts as sources for lignocellulose-based materials, thereby expanding both the biorefinery concept and feedstock supply.
|
|
