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Kwan, I., Rietzler, B. & Ek, M. (2023). Emulsions of cellulose oxalate from Norway spruce (Picea abies) bark and dissolving pulp. Holzforschung, 77(7), 554-565
Open this publication in new window or tab >>Emulsions of cellulose oxalate from Norway spruce (Picea abies) bark and dissolving pulp
2023 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 77, no 7, p. 554-565Article in journal (Refereed) Published
Abstract [en]

Tree bark is normally a side-stream product but by an integrated bark biorefinery approach, valuable compounds may be recovered and used to replace fossil-based products. Norway spruce bark was extracted to obtain cellulose, which was chemically treated to produce cellulose oxalate (COX) which was homogenized to yield nanocellulose. The nanocellulose was used to produce Pickering emulsions with almond oil and hexadecane as organic phases. COX from dissolving pulp was used to study the effect of various raw materials on the emulsifying properties. The COX samples of bark and dissolving pulp contained a significant amount of hemicelluloses, which affected the viscosity results. The emulsion properties were affected by the organic phases and the aspect ratio. Emulsions using hexadecane were more stable than the emulsions using almond oil. Since the aspect ratio of bark was lower than that of the dissolving pulp, the emulsifying properties of the COX dissolving pulp was better. It has been shown that nanocellulose from cellulose oxalate of both spruce bark and dissolving pulp is a promising substitute for petroleum-based emulsifiers and surfactants. By utilizing bark, value-added products can be produced which may be economically beneficial for various industries in the future and their aim for climate-neutral products.

Place, publisher, year, edition, pages
Walter de Gruyter GmbH, 2023
Keywords
biorefinery, nanocellulose, Norway spruce bark, Pickering emulsion
National Category
Paper, Pulp and Fiber Technology Nano Technology
Identifiers
urn:nbn:se:kth:diva-337224 (URN)10.1515/hf-2022-0191 (DOI)000999094000001 ()2-s2.0-85160846840 (Scopus ID)
Note

QC 20231002

Available from: 2023-09-28 Created: 2023-09-28 Last updated: 2023-10-02Bibliographically approved
Zhao, Y., Li, J., Yu, Q., Li, K. D., Li, Q., Zhou, R., . . . Ostrikov, K. K. (2023). Fabrication of multidimensional bio-nanomaterials from nanocellulose oxalate. Cellulose, 30(4), 2147-2163
Open this publication in new window or tab >>Fabrication of multidimensional bio-nanomaterials from nanocellulose oxalate
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2023 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 30, no 4, p. 2147-2163Article in journal (Refereed) Published
Abstract [en]

Nanocelluloses and cellulose nanomaterials derived from natural resources are a group of ideal platform materials for advanced applications. However, their synthesis through sustainable and facile processes to achieve the required properties are still challenging. Here, we prepare the nanocellulose oxalate (n-COX) from cotton with outstanding physicochemical properties by defining the optimal oxalic acid pretreatment conditions. Thus-obtained n-COX with unique 1D nanofiber shape as a platform material is further processed to various high-performance multidimensional bio-nanomaterials through several simple yet effective strategies. First, 2D n-COX films prepared through a casting-drying method show comparable or even better transparency and tensile strength than those made from other types of nanocelluloses. Second, 3D n-COX hydrogels/aerogels fabricated by a molding-crosslinking approach demonstrate good shape stability, well-preserved nanoporous networks, and qualified mechanical properties. Third, n-COX-derived bioinks display improved printability and fidelity, resulting in better size-preserving and shape-control of the 3D-bioprinted scaffolds. We expect this work could offer new insights on engineering natural cellulose and using n-COX as a platform material for further advanced fabrication, and thus, open up application potentials of this new nanocellulose.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Cellulose-based functional biomaterials, Multidimensional nanomaterials, Nanocellulose, Nanocellulose oxalate
National Category
Polymer Technologies Biomaterials Science
Identifiers
urn:nbn:se:kth:diva-330097 (URN)10.1007/s10570-022-05019-1 (DOI)000906118000002 ()2-s2.0-85145161655 (Scopus ID)
Note

QC 20230626

Available from: 2023-06-26 Created: 2023-06-26 Last updated: 2023-06-26Bibliographically approved
Chen, L., Wei, X., Wang, H., Yao, M., Zhang, L., Gellerstedt, G., . . . Min, D. (2022). A modified ionization difference UV-vis method for fast quantitation of guaiacyl-type phenolic hydroxyl groups in lignin. International Journal of Biological Macromolecules, 201, 330-337
Open this publication in new window or tab >>A modified ionization difference UV-vis method for fast quantitation of guaiacyl-type phenolic hydroxyl groups in lignin
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2022 (English)In: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 201, p. 330-337Article in journal (Refereed) Published
Abstract [en]

An ionization difference UV-Vis method (Delta epsilon-spectrum method) is the most potentially simple method for fast quantitation of phenolic hydroxyl groups (ph-OH) in lignin. However, the underestimated results were calculated from the conventional Delta epsilon-spectrum method using one- or two-point wavelengths measurement. In this study, a modified Delta epsilon-spectrum method using multi-point wavelengths measurement was developed and the negative absorbance was also considered. Four main typical lignin models, e.g. vanilla alcohol, 5-5 biphenyl, stilbenoid and vanillin, were applied as the guaiacyl-type (G-type) phenolic models for the determination of ph-OH by the modified Delta epsilon-spectrum method. The 2-methoxyethanol/water/acetic acid = 8/2/0.2 (V/V/V) was used as the acidic solvent system and the 2-methoxyethanol/0.2 M NaOH solution = 1/9 (V/V) was used as the alkaline solvent system. The ph-OH contents in the spruce milled wood lignin (SMWL) and the spruce Kraft lignin (SKL) were respectively quantified by the modified Delta epsilon-spectrum method as 1.078 and 4.348 mmol/g, which were comparable to the counterparts determined by P-31 Nuclear Magnetic Resonance Spectroscopy (P-31 NMR). The results revealed that the modified Delta epsilon-spectrum method can provide more accurate and reliable results compared to the conventional method.

Place, publisher, year, edition, pages
Elsevier BV, 2022
Keywords
Ionization difference UV-vis method, Phenolic hydroxyl groups, G-type phenolic models
National Category
Organic Chemistry Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-315832 (URN)10.1016/j.ijbiomac.2022.01.035 (DOI)000821287200003 ()35032489 (PubMedID)2-s2.0-85122701219 (Scopus ID)
Note

QC 20220721

Available from: 2022-07-21 Created: 2022-07-21 Last updated: 2022-07-21Bibliographically approved
Kwan, I., Huang, T., Ek, M., Seppänen, R. & Skagerlind, P. (2022). Bark from Nordic tree species: A sustainable source for amphiphilic polymers and surfactants. Nordic Pulp & Paper Research Journal, 37(4), 566-575
Open this publication in new window or tab >>Bark from Nordic tree species: A sustainable source for amphiphilic polymers and surfactants
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2022 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 37, no 4, p. 566-575Article in journal (Refereed) Published
Abstract [en]

Many of the amphiphilic molecules, or surfactants, are produced from fossil-based raw materials. With the increasing awareness of the climate situation, focus has shifted toward more environmentally friendly solutions to replace fossil-based products. This has led to more interest towards the forest. The circular bioeconomy is focused on making use of residues and waste and on optimizing the value of biomass over time via cascading. Nowadays, bark is seen as a waste product by industries and mainly incinerated as solid fuel. The bark contains interesting compounds but some of these are only available in low amounts, less than 1 % in the bark, while other components are present in several percentages. However, some of these components are potential candidates for the manufacture of amphiphiles and there seems to be a strong match between bark availability and surfactant demand. The global amount of bark available is approximately 359 million m3 and more than 10 million m3 of industrial bark are generated annually in Sweden and Finland. The bark of Norway spruce, Scots pine and silver birch contains approximately 25-32 % of extractives and part of these extractives has a potential as a surfactant backbone. This matches the global surfactant demand of about 15.6 million tons. Therefore, industrial bark has a significant potential value as a raw material source for amphiphilic molecules and polymers. This review focuses on betulin, condensed tannin and suberin. These compounds have been studied on individually and methods to extract them out from the bark are well investigated, but to utilize them as amphiphilic compounds has not been explored. With this review, we want to emphasis the potential of using bark, what today is seen as a waste product, as a raw material for production of amphiphiles. Moreover, a techno-economic analysis has been performed on betulin, tannins and suberin. 

Place, publisher, year, edition, pages
Walter de Gruyter GmbH, 2022
Keywords
Amphiphiles, bark, betulin, suberin, tannin, Components, Molecules, Polymers, Production, Review, Wastes, Economic analysis, Flavonoids, Fuels, Wood, Amphiphilic molecules, Amphiphilic polymers, Amphiphilic surfactants, Finland, Solid fuels, Tree species, Waste products, Tannins
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-327250 (URN)10.1515/npprj-2022-0003 (DOI)000852794200001 ()2-s2.0-85138236438 (Scopus ID)
Note

QC 20230524

Available from: 2023-05-24 Created: 2023-05-24 Last updated: 2023-05-24Bibliographically approved
Bengtsson, A., Landmer, A., Norberg, L., Yu, S., Ek, M., Brännvall, E. & Sedin, M. (2022). Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process. FIBERS, 10(12), Article ID 108.
Open this publication in new window or tab >>Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process
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2022 (English)In: FIBERS, ISSN 2079-6439, Vol. 10, no 12, article id 108Article in journal (Refereed) Published
Abstract [en]

In recent years, there has been extensive research into the development of cheaper and more sustainable carbon fiber (CF) precursors, and air-gap-spun cellulose-lignin precursors have gained considerable attention where ionic liquids have been used for the co-dissolution of cellulose and lignin. However, ionic liquids are expensive and difficult to recycle. In the present work, an aqueous solvent system, cold alkali, was used to prepare cellulose-lignin CF precursors by wet spinning solutions containing co-dissolved dissolving-grade kraft pulp and softwood kraft lignin. Precursors containing up to 30 wt% lignin were successfully spun using two different coagulation bath compositions, where one of them introduced a flame retardant into the precursor to increase the CF conversion yield. The precursors were converted to CFs via batchwise and continuous conversion. The precursor and conversion conditions had a significant effect on the conversion yield (12-44 wt%), the Young's modulus (33-77 GPa), and the tensile strength (0.48-1.17 GPa), while the precursor morphology was preserved. Structural characterization of the precursors and CFs showed that a more oriented and crystalline precursor gave a more ordered CF structure with higher tensile properties. The continuous conversion trials highlighted the importance of tension control to increase the mechanical properties of the CFs.

Place, publisher, year, edition, pages
MDPI AG, 2022
Keywords
bio-based, carbon fiber, cellulose, cold alkali, lignin
National Category
Paper, Pulp and Fiber Technology Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-323226 (URN)10.3390/fib10120108 (DOI)000900718200001 ()2-s2.0-85144640702 (Scopus ID)
Note

QC 20230125

Available from: 2023-01-25 Created: 2023-01-25 Last updated: 2023-01-25Bibliographically approved
Rietzler, B., Karlsson, M., Kwan, I., Lawoko, M. & Ek, M. (2022). Fundamental Insights on the Physical and Chemical Properties of Organosolv Lignin from Norway Spruce Bark.. Biomacromolecules, 23(8), 3349-3358
Open this publication in new window or tab >>Fundamental Insights on the Physical and Chemical Properties of Organosolv Lignin from Norway Spruce Bark.
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2022 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 8, p. 3349-3358Article in journal (Refereed) Published
Abstract [en]

The interest in the bark and the attempt to add value to its utilization have increased over the last decade. By applying an integrated bark biorefinery approach, it is possible to investigate the recovery of compounds that can be used to develop green and sustainable alternatives to fossil-based materials. In this work, the focus is on extracting Norway spruce (Picea abies) bark lignin via organosolv extraction. Following the removal of the extractives and the subcritical water extraction to remove the polysaccharides, a novel cyclic organosolv extraction procedure was applied, which enabled the recovery of lignin with high quality and preserved structure. Main indicators for low degradation and preservation of the lignin structure were a high β-O-4' content and low amounts of condensed structures. Furthermore, high purity and low polydispersity of the lignin were observed. Thus, the obtained lignin exhibits high potential for use in the direct development of polymer precursors and other bio-based materials. During the extraction sequence, around 70% of the bark was extracted. Besides the lignin, the extractives as well as pectic polysaccharides and hemicelluloses were recovered with only minor degradation, which could potentially be used for the production of biofuel or other high-value products such as emulsifiers or adhesives.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-316320 (URN)10.1021/acs.biomac.2c00457 (DOI)000828106500001 ()35815507 (PubMedID)2-s2.0-85135600359 (Scopus ID)
Note

QC 20220812

Available from: 2022-08-12 Created: 2022-08-12 Last updated: 2023-09-28Bibliographically approved
Kittikorn, T., Strömberg, E., Ek, M. & Karlsson, S. (2022). Influence of sisal fibre modification on the microbial stability of poly(hydroxybutyrate-co-valerate): thermal analysis. Polimery, 67(3), 93-101
Open this publication in new window or tab >>Influence of sisal fibre modification on the microbial stability of poly(hydroxybutyrate-co-valerate): thermal analysis
2022 (English)In: Polimery, ISSN 0032-2725, Vol. 67, no 3, p. 93-101Article in journal (Refereed) Published
Abstract [en]

The effect of modification of sisal fibre with propionic anhydride and vinyltrimethoxy silane on the microbiological stability of poly(hydroxybutyrate-co-valerate) (PHBV) was investigated. The effect of the coupling agent - PHBV grafted with maleic anhydride (PHBV-g-MA) was also investigated. The best adhesion at the interface was observed for propionylation of sisal fibre, which improved the thermal properties of the composites. Composites with modified sisal fibre were characterized by higher activation energy (155 kJ/mol), which is related to stronger interactions at the matrix-fibre interface. In the microbial growth test, all biocomposites showed a decrease in molecular weight due to enzymatic degradation by Aspergillus niger. The most resistant to microorganisms was the composite containing propionylated sisal fibre. DMTA and TGA also confirmed the highest microbiological stability of the composite with the addition of propionylated sisal fibre, as evidenced by the smallest change in the properties after the microbiological growth test. In contrast, PHBV-g-MA caused significant enzymatic degradation due to the presence of large amorphous regions.

Place, publisher, year, edition, pages
INDUSTRIAL CHEMISTRY RESEARCH INST, 2022
Keywords
poly(hydroxybutyrate-co-valerate), sisal fibre, surface modification, thermal analysis, micro-bial stability
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-312691 (URN)10.14314/polimery.2022.3.1 (DOI)000790520400001 ()2-s2.0-85132118462 (Scopus ID)
Note

QC 20220524

Available from: 2022-05-24 Created: 2022-05-24 Last updated: 2022-12-19Bibliographically approved
Zhang, Q., Zhang, H., Wu, Z., Wang, C., Zhang, R., Yang, C., . . . Fahlman, M. (2022). Natural Product Betulin-Based Insulating Polymer Filler in Organic Solar Cells. Solar RRL, 6(9), Article ID 2200381.
Open this publication in new window or tab >>Natural Product Betulin-Based Insulating Polymer Filler in Organic Solar Cells
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2022 (English)In: Solar RRL, E-ISSN 2367-198X, Vol. 6, no 9, article id 2200381Article in journal (Refereed) Published
Abstract [en]

Introduction of filler materials into organic solar cells (OSCs) are a promising strategy to improve device performance and thermal/mechanical stability. However, the complex interactions between the state-of-the-art OSC materials and filler require careful selection of filler materials and OSC fabrication to achieve lower cost and improved performance. In this work, the introduction of a natural product betulin-based insulating polymer as filler in various OSCs is investigated. Donor–acceptor–insulator ternary OSCs are developed with improved open-circuit voltage (Voc) due to decreased trap-assisted recombination. Furthermore, filler-induced vertical phase separation due to mismatched surface energy can strongly affect charge collection at the bottom interface and limit the filler ratio. A quasi-bilayer strategy is used in all-polymer systems to circumvent this problem. Herein, the variety of filler materials in OSCs to biomass is broadened, and the filler strategy is made a feasible and promising strategy toward highly efficient, eco, and low-cost OSCs.

Place, publisher, year, edition, pages
Wiley, 2022
Keywords
betulin, Filler strategy, organic solar cells, Filled polymers, Fillers, Open circuit voltage, Phase separation, Cell-be, Cell/B.E, Cell/BE, Filler materials, Insulating polymer, Low-costs, Natural products, Polymer-filler
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:kth:diva-324565 (URN)10.1002/solr.202200381 (DOI)000809737000001 ()2-s2.0-85131559142 (Scopus ID)
Note

QC 20230308

Available from: 2023-03-08 Created: 2023-03-08 Last updated: 2023-03-08Bibliographically approved
Távora de Mello Soares, C., Ek, M., Ostmark, E., Gallstedt, M. & Karlsson, S. (2022). Recycling of multi-material multilayer plastic packaging: Current trends and future scenarios. Resources, Conservation and Recycling, 176, Article ID 105905.
Open this publication in new window or tab >>Recycling of multi-material multilayer plastic packaging: Current trends and future scenarios
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2022 (English)In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 176, article id 105905Article in journal (Refereed) Published
Abstract [en]

Multi-material multilayer plastic packaging (MMPP) is widely applied in fast moving consumer goods (FMCG) combining functionalities of distinct materials. These packaging structures can enhance properties, such as resource-use efficiency and barrier performance leading to consequential benefits like a prolonged shelf-life. Nevertheless, they represent a challenge for existing recycling systems, confronting circular economy principles. This study aim was to foresight the future of recycling technologies for MMPP in the next five to ten years. Future scenarios were identified, including (1) high-performance material recycling, (2) recycling into hydrocarbons, (3) business as usual, and (4) downcycling. In-depth interviews and a feedback survey were methods used to validate the scenario matrix while defining experts' expectations towards the future. The analysis showed that distinct technologies will develop unevenly in different parts of the world. A mix of all scenarios is probable in the upcoming years, depending, essentially, on regulations and technology availability. Advanced high-performance material recycling encounters systemic bottlenecks, such as insufficient sorting technology for post-consumer waste. In contrast, chemical recycling (feedstock) is concentrating investments as a solution, requiring low input-characterization. Additionally, design for recycling trends might reduce multilayers' complexity. A gap between recycling targets and recycling technologies was identified, representing short-term opportunities for more sustainable materials, such as bio-based.

Place, publisher, year, edition, pages
Elsevier BV, 2022
Keywords
Multi-material multilayer packaging, Plastic packaging recycling, Advanced recycling technologies, Future foresight, Scenario planning
National Category
Economics Other Environmental Engineering Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-304565 (URN)10.1016/j.resconrec.2021.105905 (DOI)000708339400001 ()2-s2.0-85115942776 (Scopus ID)
Note

QC 20211108

Available from: 2021-11-08 Created: 2021-11-08 Last updated: 2024-03-15Bibliographically approved
Rietzler, B. & Ek, M. (2021). Adding Value to Spruce Bark by the Isolation of Nanocellulose in a Biorefinery Concept. ACS Sustainable Chemistry and Engineering, 9(3), 1398-1405
Open this publication in new window or tab >>Adding Value to Spruce Bark by the Isolation of Nanocellulose in a Biorefinery Concept
2021 (English)In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 9, no 3, p. 1398-1405Article in journal (Refereed) Published
Abstract [en]

It is shown that the isolation of nanocellulose in a biorefinery approach adds value to the bark and its components. The utilization of a chlorine-free delignification and the preparation of cellulose oxalate in a solvent-free process are an economic and environmentally advantageous way of applying the biorefinery concept and to use the bark in a sustainable way. The properties of cellulose oxalate from delignified bark were determined, and the morphological structure of the isolated nanocellulose was characterized. The chemical composition and thermal properties were monitored during the extraction and separation steps, and it was possible to prepare cellulose oxalate in a yield of 82% with a degree of substitution of 0.3 and surface charge of 1.53 mmol g(-1). The isolated nanocellulose was found to be a mixture of rodlike nanocrystals and nanofibrils. Initial thermal analysis of the isolated nanocellulose shows promising properties. The results show that the bark is a potential inexpensive source of high-value nanocellulose that can be isolated in high yield, for use in cosmetics or as reinforcement in nanocomposites. Since the isolated nanocellulose contains two different morphological types, it can be used where the properties of both cellulose nanocrystals and cellulose nanofibrils are required.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2021
Keywords
biorefinery, cellulose oxalate, nanocellulose, Norway spruce bark, sustainability, TCF delignification
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-292159 (URN)10.1021/acssuschemeng.0c08429 (DOI)000613726300035 ()2-s2.0-85099995388 (Scopus ID)
Note

QC 20210326

Available from: 2021-03-26 Created: 2021-03-26 Last updated: 2022-06-25Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3858-8324

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