| 1. |
- Baker, Darren A., et al.
(författare)
-
Opportunities in lignin based carbon fibre
- 2015
-
Ingår i: NWBC 2015. - Espoo : VTT. - 9789513883539 ; , s. 244-251
-
Konferensbidrag (refereegranskat)abstract
- Innventia AB's LignoBoost process enables the extraction of high purity lignin efficiently from the black liquor in kraft mills. A stream of black liquor is taken from the evaporation plant and the lignin is precipitated by acidification and filtered. The filter cake is redispersed and acidified and the resulting slurry is filtered and washed. High purity lignin can be produced at several scales, namely 10g, 1kg, 10kg and over 1,000kg. Innventia has invested significantly to demonstrate the potential of lignin as a viable feedstock for carbon fibre manufacture. Initially, the fibre melt spinning performance of the lignin is assessed using single filament melt extrusion and then melt spinning is performed at the multifilament scale, where fine fibres can be produced for conversion to carbon fibre. Oxidative thermostabilisation of the lignin fibres is carried out so that carbonisation can proceed. The effects of thermal treatment programmes and tensioning have been studied by using either thermomechanical analysis or by using test equipment specially designed to monitor carbonisation profiles with either stress or strain control. In addition, continuous processes for the conversion of lignin fibre to carbon fibre are being developed.
|
|
| 2. |
- Baker, Darren A, et al.
(författare)
-
Structural carbon fibre from kraft lignin
- 2017
-
Ingår i: The 7th Nordic Wood Biorefinery Conference held in Stockholm, Sweden, 28-30 Mar. 2017. - Stockholm : RISE Bioekonomi. - 9789186018207 ; , s. 65-67
-
Konferensbidrag (refereegranskat)abstract
- The GreenLight consortium is working to demonstrate a biobased, renewable and economically viable carbon fibre from lignin. The aim is to provide a basis for commercial production of lignin, lignin filaments, carbon fibre and carbon fibre composites. The most difficult boundary to success in the developing lignin as a precursor for continuous filament carbon fibre has been identified as melt extrusion of lignin. The consortium is working to develop a robust melt spinning platform for use up to the 1,000 filament scale. Methodical studies have been performed to examine lignin separation from differing black liquors derived from both softwood and hardwood and assess their viability in terms of thermal, compositional and structural properties. The move will then be made to pilot scale melt spinning at the 100 filament scale. The characteristics of some kraft lignin fractions obtained from the same Sodra Monsteras softwood kraft black liquor have been studied. The lignins were manufactured in quantities of approximately 10-20kg. Several variations of the LignoBoost process were used to provide lignins with improved melt spinning properties. The lignins were of high purity, each having low carbohydrate, extractives and inorganic contents. All four lignins could be melt spun and converted to carbon fibre.
|
|
| 3. |
- Baker, Darren, et al.
(författare)
-
Lignin-based carbon fiber : effect of softwood kraft lignin separation method on multifilament melt-spinning performance and conversion
- 2019
-
Ingår i: 20th International symposium on wood, fiber, and pulping chemistry.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A reference lignin separated from an industrial softwood kraft black liquor via an improved LignoBoost process was compared to four other lignins derived from the same liquor. The four lignins were produced by using a) pH-fractionation within the LignoBoost process, b) ultrafiltration of black liquor prior to the LignoBoost process, and c) solvent leaching of the reference lignin using methanol and d) ethanol.Lignin compositional characteristics and thermal properties were compared, and monofilament extrusion used to assess their potential for successful melt spinning at the 24 filament scale. The lignin prepared by ethanol leaching of the reference lignin was found to be most appropriate for potential pilot scale fibre production. This was owing to a high purity, lower comparative glass transition temperature (Tg), and good spinning performance.Thermal pretreatments of the ethanol leached lignin gave a selection of enhanced lignins which were characterized for comparison, and melt spun on pilot multifilament equipment. The enhanced lignins could be continuously melt spun giving filaments with diameters as low as 10 μm and with minimal defects. Conversion of selected filaments provided carbon fibres with a tensile strength of 1259 ± 159 MPa, tensile modulus of 67 ± 3 GPa and diameter of 7.3 ± 0.5 μm.
|
|
| 4. |
- Mandalika, A., et al.
(författare)
-
Potential of natural-origin loblolly pine tree fractions as a bioenergy feedstock
- 2019
-
Ingår i: Wood and Fiber Science. - : Society of Wood Science and Technology. - 0735-6161. ; 51:1, s. 26-40
-
Tidskriftsartikel (refereegranskat)abstract
- Chemical characterization was performed on 10 different samples of loblolly pine (Pinus taeda L.), representing the various woody components of trees (bole, slab, tops and branches, and precommercial stem-only) harvested from two naturally regenerated forests in southern Arkansas. Ultimate analysis, proximate analysis using thermogravimetry, and the energy content of the samples were determined to help evaluate their bioenergy utility. Elemental analysis revealed no significant differences between the pine tree fractions, whereas differences were observed in the proximate analysis, particularly in regard to the fixed carbon content. Generally, proximate analyses did not show significant differences between the slabwood and bolewood samples, although the “tops and branches†and “whole stem†samples contained the lowest volatile matter amounts and the greatest amounts of fixed carbon and ash content. In terms of the calorific value, the “tops and limbs†sample reported the lowest energy content, whereas the “whole stem†sample was among the highest reported value with statistical significance. These results indicate that whole stem samples may be an attractive prospect for bioenergy applications such as gasification, pelletization, and combustion, owing to favorable heating content values and relatively low ash content. Although a number of logistical challenges exist in their acquisition and processing, slabs, topwood, and branches offer opportunities for bioenergy applications that can increase the utilization of forest residues without threatening more traditional uses of wood in lumber, panels, and paper. Finally, we then briefly consider the silvicultural implications of these results for naturally regenerated southern pine €“dominated forests.
|
|
| 5. |
- Nowak, Andrzej, et al.
(författare)
-
Lignin-based carbon fibers for renewable and multifunctional lithium-ion battery electrodes
- 2018
-
Ingår i: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 72:2, s. 81-90
-
Tidskriftsartikel (refereegranskat)abstract
- Lignin-based carbon fibers (LCFs) from the renewable resource softwood kraft lignin were synthesized via oxidative thermostabilization of pure melt-spun lignin and carbonization at different temperatures from 1000 degrees C to 1700 degrees C. The resulting LCFs were characterized by tensile testing, scanning electron microscopy (SEM), X-ray diffraction (XRD) and confocal Raman spectroscopy. The microstructure is mainly amorphous carbon with some nanocrystalline domains. The strength and stiffness are inversely proportional to the carbonization temperature, while the LCFs carbonized at 1000 degrees C exhibit a strength of 628 MPa and a stiffness of 37 GPa. Furthermore, the application potential of LCFs was evaluated as negative electrodes in a lithium-ion battery (LIB) by electrochemical cycling at different current rates in a half-cell setup. The capacity drops with the carbonization temperature and the LCFs carbonized at 1000 degrees C have a capacity of 335 mAh g(-1). All LCFs showed good cycling stability. Because of the mechanical integrity and conductivity of the LCFs, there is no need to apply current collectors, conductive additives or binders. The advantage is an increased gravimetric energy density compared to graphite, which is the most common negative electrode material. LCFs show a promising multifunctional behavior, including good mechanical integrity, conductivity and an ability to intercalate lithium for LIBs.
|
|
| 6. |
- Schlee, Philipp, et al.
(författare)
-
Free-standing supercapacitors from kraft lignin nanofibers with remarkable volumetric energy density
- 2019
-
Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6539. ; 10:10, s. 2980-2988
-
Tidskriftsartikel (refereegranskat)abstract
- We have discovered a very simple method to address the challenge associated with the low volumetric energy density of free-standing carbon nanofiber electrodes for supercapacitors by electrospinning Kraft lignin in the presence of an oxidizing salt (NaNO3) and subsequent carbonization in a reducing atmosphere. The presence of the oxidative salt decreases the diameter of the resulting carbon nanofibers doubling their packing density from 0.51 to 1.03 mg cm−2 and hence doubling the volumetric energy density. At the same time, the oxidative NaNO3 salt eletrospun and carbonized together with lignin dissolved in NaOH acts as a template to increase the microporosity, thus contributing to a good gravimetric energy density. By simply adjusting the process parameters (amount of oxidizing/reducing agent), the gravimetric and volumetric energy density of the resulting lignin free-standing carbon nanofiber electrodes can be carefully tailored to fit specific power to energy demands. The areal capacitance increased from 147 mF cm−2 in the absence of NaNO3 to 350 mF cm−2 with NaNO3 translating into a volumetric energy density increase from 949 μW h cm−3 without NaNO3 to 2245 μW h cm−3 with NaNO3. Meanwhile, the gravimetric capacitance also increased from 151 F g−1 without to 192 F g−1 with NaNO3.
|
|
| 7. |
- Schlee, Philipp, et al.
(författare)
-
From waste to wealth : From kraft lignin to free-standing supercapacitors
- 2019
-
Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 145, s. 470-480
-
Tidskriftsartikel (refereegranskat)abstract
- Pure eucalyptus Kraft lignin derived carbon fiber mats were produced based on a model workflow. It covers the preparation and characterization of the lignin precursor and the carbon materials and its testing in the final application (supercapacitor). Sequential solvent extraction was employed to produce a eucalyptus Kraft lignin precursor which could be electrospun into lignin fibers without any additives. The fiber formation from low molecular weight lignin is assigned to strong intermolecular interactions via hydrogen bonding and π-π-stacking between individual lignin macromolecules which gives rise to association complexes in the electrospinning solution. By stabilization in air, carbonization in N2 and an activation step in CO2, free-standing microporous carbon fiber mats could be produced. These fiber mats possess mainly basic oxygen functional groups which proved to be beneficial when tested as free-standing electrodes in symmetric supercapacitors. Consequently, the CO2-activated fiber mats showed a high specific gravimetric capacitance of 155 F/g at 0.1 A/g, excellent rate capability with 113 F/g at 250 A/g and good capacitance retention of 94% after 6000 cycles when tested in 6 M KOH electrolyte. Therefore, we conclude that lignin itself is a promising precursor to produce microporous, oxygen functionalized carbon fibers serving as free-standing electrodes in aqueous supercapacitors.
|
|
| 8. |
- Schweinebarth, Hannah, et al.
(författare)
-
Lignin: evaluation of properties for applications
- 2015
-
Ingår i: NWBC 2015. - Espoo : VTT. - 9789513883539 ; , s. 387-388
-
Konferensbidrag (refereegranskat)abstract
- Utilization of abundant lignin-rich natural resources will provide new revenue streams for today’s kraft pulp mills. Owing to its phenol-rich structure, Lignin is very versatile and has much potential for application in many areas, for example: as a foundation for bulk chemical production, for conversion to fuel products, a binder material, a fertilizer, anti-oxidant, as a precursor for carbon fibres and nanofibres and for activated carbons.
|
|
| 9. |
- Tempest, Nicola, et al.
(författare)
-
Histological 3D reconstruction and in vivo lineage tracing of the human endometrium
- 2020
-
Ingår i: Journal of Pathology. - : WILEY. - 0022-3417 .- 1096-9896. ; 251:4, s. 440-451
-
Tidskriftsartikel (refereegranskat)abstract
- Regular menstrual shedding and repair of the endometrial functionalis is unique to humans and higher-order primates. The current consensus postulates endometrial glands to have a single-tubular architecture, where multi-potential stem cells reside in the blind-ending glandular-bases. Utilising fixed samples from patients, we have studied the three-dimensional (3D) micro-architecture of the human endometrium. We demonstrate that some non-branching, single, vertical functionalis glands originate from a complex horizontally interconnecting network of basalis glands. The existence of a multipotent endometrial epithelial stem cell capable of regenerating the entire complement of glandular lineages was demonstrated byin vivolineage tracing, using naturally occurring somatic mitochondrial DNA mutations as clonal markers. Vertical tracking of mutated clones showed that at least one stem-cell population resides in the basalis glands. These novel findings provide insight into the efficient and scar-less regenerative potential of the human endometrium. (c) 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
|
|
| 10. |
- Uhlin, Anders, et al.
(författare)
-
Kraft lignin based carbon fibres
- 2017
-
Ingår i: The 7th Nordic Wood Biorefinery Conference held in Stockholm, Sweden, 28-30 Mar. 2017. - Stockholm : RISE Bioekonomi. - 9789186018207 ; , s. 258-259
-
Konferensbidrag (refereegranskat)abstract
- Research has been carried out at RISE Bioeconomy into converting lignin to carbon fibres, focusing on melt spinning of kraft lignin to filaments, which were subsequently converted to carbon fibres. New equipment has been installed to improve the properties of the lignin based carbon fibres and now it is possible to produce carbon fibres with equal or even better properties compared with published data on lignin based carbon fibres. For a melt spun softwood kraft lignin that was converted to carbon fibres, the tensile strength had an average value of 952MPa, while the Young's modulus average value was 69GPa. A toy car demonstrator has been produced in a project financed by the Bioinnovation, a research programme by VINNOVA, Formas and the Swedish Energy Agency. The existing roof of the car was replaced with one consisting of a carbon fibre composite, in which the carbon fibres were made of 100% softwood kraft lignin. A lithium ion battery as also installed into the toy car, having a negative electrode containing lignin based carbon fibres
|
|
