[article-cris] Kemian tekniikan korkeakoulu / CHEM

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Fabrication of biocomposite materials with polycaprolactone and activated carbon extracted from agricultural waste
(Elsevier Science B.V., 2024-12-05) Mollaei, Mehrad; Karbasi, Farnaz; Sharifi Haddad, Amin; Baniasadi, Hossein; Department of Chemical and Metallurgical Engineering; Polymer Synthesis Technology; Polymer technology; Islamic Azad University; University of Aberdeen
In this study, activated carbon was extracted from a source of agricultural waste (wheat straw) through a chemical activation process and blended with polycaprolactone (PCL) to fabricate new biocomposite materials. Three distinct types of activated carbon, designated as C1, C2, and C3 were obtained by varying the ratio of the activation agent and wheat straw and different drying conditions. Through a comprehensive array of analytical techniques, including FTIR, XRD, BET, EDS, and FE-SEM, we determined the optimal experimental method for extracting activated carbon from wheat straw and identified the most effective type of activated carbon (C3). Based on these analyses, C3 exhibits the highest carbon content, the greatest specific surface area (386.47 m2/g), and the highest total pore volume (0.2596 cm3/g). By blending polycaprolactone with the optimal activated carbon (at concentrations of 1, 3, and 5 wt%), biocomposite samples were fabricated. The results of FTIR indicate that the biocomposite materials containing 1, 3, and 5 wt% of activated carbon exhibit no disturbing peaks. However, the sample PCL-C,1 wt%, shows significant increases in the intensity of observed peaks. XRD analyses of the fabricated biocomposite samples illustrate that the sample containing 1 wt% of activated carbon has a greater tendency for crystallization compared to the other samples. Morphological analysis of the biocomposites and the dispersion of carbon particles within them demonstrate the least amount of agglomeration in the sample with an activated carbon concentration of 1 wt%. Upon assessing the mechanical properties of biocomposites, the same sample (1 wt% of C3) demonstrates more favorable characteristics than the other samples. Furthermore, a contact angle test was conducted to gauge the biocomposite hydrophilicity, revealing a 7 degree increase in contact angle for the sample with an activated carbon concentration of 1 wt% compared to the pure PCL sample. Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to examine the weight loss, degradation temperature, melting temperature, and glass transition temperature of the synthesized materials. These analyses indicate a marginal augmentation in both melting and glass transition temperatures for the sample with an activated carbon concentration of 1 wt%.
Monodispersed Renewable Particles by Cascade and Density Gradient Size Fractionation to Advance Lignin Nanotechnologies
(Wiley-VCH Verlag, 2024-08-22) Chen, Jingqian; Tian, Jing; Feng, Nianjie; Ning, Like; Wang, Dong; Zhao, Bin; Guo, Tianyu; Song, Junlong; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; University of British Columbia; Nanjing Forestry University
Control over particle size and shape heterogeneity is highly relevant to the design of photonic coatings and supracolloidal assemblies. Most developments in the area have relied on mineral and petroleum-derived polymers that achieve well-defined chemical and dimensional characteristics. Unfortunately, it is challenging to attain such control when considering renewable nanoparticles. Herein, a pathway toward selectable biobased particle size and physicochemical profiles is proposed. Specifically, lignin is fractionated, a widely available heterogeneous polymer that can be dissolved in aqueous solution, to obtain a variety of monodispersed particle fractions. A two-stage cascade and density gradient centrifugation that relieves the need for solvent pre-extraction or other pretreatments but achieves particle bins of uniform size (~60 to 860 nm and polydispersity, PDI<0.06, dynamic light scattering) along with characteristic surface chemical features is introduced. It is found that the properties and associated colloidal behavior of the particles are suitably classified in distinctive size populations, namely, i) nanoscale (50–100 nm), ii) photonic (100–300 nm) and iii) near-micron (300–1000 nm). The strong correlation that exists between size and physicochemical characteristics (molar mass, surface charge, bonding and functional groups, among others) is introduced as a powerful pathway to identify nanotechnological uses that benefit from the functionality and cost-effectiveness of biogenic particles.
Source separation and anaerobic co-digestion of blackwater and food waste for biogas production and nutrient recovery
(IWA Publishing, 2024-08-01) Kamravamanesh, Donya; Kokko, Marika; Department of Bioproducts and Biosystems; Tampere University
Anaerobic co-digestion of source-separated blackwater (BW) and food and kitchen waste (FW) offers decentralized circular economy solutions by enabling local production of biogas and nutrient-rich byproducts. In this study, a 2 m3 pilot-scale continuously stirred tank reactor (CSTR) operated under mesophilic conditions was utilized for co-digestion of BW and FW. The process obtained a CH4 yield of 0.7 ± 0.2 m3/kg influent-volatile solid (VS), reaching a maximum yield of 1.1 ± 0.1 m3/kg influent-VS, with an average organic loading rate of 0.6 ± 0.1 kg-VS/m3/d and HRT of 25 days. The CH4 production rate averaged 0.4 ± 0.1 m3/m3/d, peaking at 0.6 ± 0.1 m3/m3/d. Treatment of digestate through flocculation followed by sedimentation recovered over 90% of ammonium nitrogen and potassium, and 80-85% of total phosphorus in the liquid fraction. This nutrient-rich liquid was used to cultivate Chlorella vulgaris, achieving a biomass concentration of 1.2 ± 0.1 g/L and 85 ± 3% and 78 ± 5% ammonium nitrogen and phosphorus removal efficiency, respectively. These findings not only highlight the feasibility of anaerobic co-digestion of source-separated BW and FW in local biogas production but also demonstrate the potential of microalgae cultivation as a sustainable approach to converting digestate into nutrient-rich algae biomass.
Recent antibacterial agents from biomass derivatives : Characteristics and applications
(SCI-Direct Publishing, 2024-08) Solihat, Nissa Nurfajrin; Hidayat, Alif Faturahman; Ilyas, R. A.; Thiagamani, Senthil Muthu Kumar; Azeele, Nur Izyan Wan; Sari, Fahriya Puspita; Ismayati, Maya; Bakshi, Mohammad Irfan; Garba, Zaharaddeen N.; Hussin, M. Hazwan; Restu, Witta Kartika; Syafii, Wasrin; Ariyanta, Harits Atika; Fatriasari, Widya; Department of Bioproducts and Biosystems; Bioproduct Chemistry; National Research and Innovation Agency (BRIN); Universiti Teknologi Malaysia; Kalasalingam University; Ahmadu Bello University; Universiti Sains Malaysia; IPB University
Enhancing awareness of personal cleanliness and antibacterial resistance has intensified the antibacterial substance request on consumable products. Antibacterial agents that have been commercialized nowadays are produced from inorganic and non-renewable substances. This provides several drawbacks, particularly against health and environmental issues. Therefore, many scientists work on substituting fossil-fuel-based antibacterial agents with natural ones such as from biomass. Biomass derivatives, natural abundances of biopolymers in the world, amount to major compounds including polysaccharides (cellulose, hemicellulose, and chitosan) and polyphenol (tannin and lignin) substances which are capable to combat the growth of Gram-positive bacteria and Gram-negative bacteria. To date, no report focuses on a deep understanding of antibacterial properties derived from biomass and the internal and external factors effects. This work provides that gap because comprehensive knowledge is necessary before applying biomass to the products. The potency of biomass derivatives as antibacterial additives is also summarized. Basic knowledge of antibacterial characteristics to the application in products is highlighted in this review. Besides, the discussion about challenges and future perspectives is also delivered.
Spin-dyeing of cellulose fibres with vat dyes using the Ioncell process
(Elsevier Science Ltd., 2024-12-15) Nygren, Nicole; Schlapp-Hackl, Inge; Heimala, Senni; Sederholm, Helena; Rissanen, Marja; Hummel, Michael; Department of Bioproducts and Biosystems; Biopolymer Chemistry and Engineering; Textile Chemistry
Estimated 20 % of global clean water pollution is attributed to textile production. Dyeing and finishing processes use an extensive amount of water and chemicals, and most of the effluents and wastewater is released into the environment. In this study, we explore spin-dyeing of man-made cellulosic fibres (MMCFs) with vat dyes using the Ioncell process, circumventing the ubiquitous use of fresh water and potentially reducing effluents streams to a great extent. Spin-dyeing is an established process for synthetic polymers but is not common for MMCFs. Regenerated cellulose fibres were produced through dissolution of dissolving pulp in the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene acetate. The produced fibres were processed into yarn and a jersey fabric was knitted. Mechanical and colour fastness properties were tested. The fibres properties were also assessed through SEM, birefringence, and crystallinity measurements. Fibres with excellent mechanical properties (tenacity higher than 50 cN/tex) and colour fastness were produced, with most samples receiving the highest or next highest performance grade. The spun-dyed fibres also hold great potential to be recycled themselves without colour change or loss in colour intensity. Textiles with colours produced in large quantities such as black or navy blue could be the first market entry point.
Development and characterization of polylactic acid/starch biocomposites – From melt blending to preliminary life cycle assessment
(Elsevier, 2024-11) Baniasadi, Hossein; Äkräs, Laura; Madani, Zahra; Silvenius, Frans; Fazeli, Mahyar; Lipponen, Sami; Vapaavuori, Jaana; Seppälä, Jukka; Department of Chemical and Metallurgical Engineering; Department of Chemistry and Materials Science; Department of Bioproducts and Biosystems; Polymer Synthesis Technology; Polymer technology; Multifunctional Materials Design; Bioproduct Technology; Natural Resources Institute Finland (Luke)
This study presents a comprehensive analysis encompassing melt blending, characterization, life cycle assessment (LCA), and 3D printing of a range of polylactic acid (PLA)/starch biocomposites, with starch content varying from 0 to 50 wt%. To enhance compatibility between the starch particles and the PLA matrix, we utilized a solvent-free method to graft N-octadecyl isocyanate (ODI) molecules onto the surface of the starch particles, resulting in ODI-g-starch, which yielded several improved properties. Notably, toughness and elongation at break improved by approximately 170 % and 300 %, respectively. Moreover, the crystallinity increased from 11.6 % in plain PLA to 30.1 %, suggesting that the uniform dispersion of ODI-g-starch particles acted as nucleating sites for the crystallization of PLA chains. Additionally, viscosity decreased significantly with the introduction of ODI-g-starch particles, indicating their plasticizing effect, thereby enhancing the processability and ease of fabrication of the biocomposite. Crucially, our LCA analysis revealed a significant reduction in the carbon footprint of these biocomposites, up to 18 % and 63 %, compared to plain PLA and selected fossil-based plastics, respectively, upon the incorporation of ODI-g-starch. In summary, our research introduces the newly developed PLA/starch biocomposites as a sustainable and eco-friendly alternative to commercially available plain PLA and specific fossil-based plastics.
Carbon Aerogels Derived from Anion-Modified Nanocellulose for Adaptive Supercapacitor Performance
(Wiley-VCH Verlag, 2024-07-10) Al Haj, Yazan; Soliman, Ahmed B.; Vapaavuori, Jaana; Elbahri, Mady; Department of Chemistry and Materials Science; Multifunctional Materials Design; Nanochemistry and Nanoengineering
In the pursuit of developing advanced carbon aerogel (CA) supercapacitors, a rational design approach is introduced that utilizes often overlooked conjugated anions to modulate the properties of CAs. Ionic cross-linking of cellulose nanocrystal (CNC) aerogels ensures the preservation of structural integrity even after carbonization. Interestingly, anion selection not only influences the cross-linking and carbonization processes but also significantly modulates the electrochemical performance of the resulting CAs. This is found to be vital in optimizing the overall supercapacitor performance. Electro-assisted (EA) wetting of the electrodes procures an adaptive and progressive performance enhancement, heralding the advent of sustainable supercapacitors crafted from earth-abundant materials.
Electron Donating Functional Polymer Dielectrics to Reduce the Threshold Voltage of n-Type Organic Thin-Film Transistors
(John Wiley & Sons, 2024-08) Ronnasi, Bahar; King, Benjamin; Brixi, Samantha; Swaraj, Sufal; Niskanen, Jukka; Lessard, Benoît H.; Department of Chemical and Metallurgical Engineering; Polymer Synthesis Technology; University of Ottawa; Synchrotron Soleil
Low-cost and high-performance electronics based on synthetically simple materials are required to fuel the deployment of smart packaging and wearable electronics. Metal phthalocyanines (MPcs) are promising semiconductors for use in n-type organic thin film transistors (OTFTs) but often require high operating voltages. The first silicon phthalocyanine-based OTFT with a polymer dielectric is reported as an alternative to traditional metal oxide dielectrics. Incorporating poly(methyl methacrylate) (PMMA) as the dielectric successfully reduces the threshold voltage (VT) of bispentafluorophenoxy SiPc (F10-SiPc) from 14.9V to 7.3V while retaining high mobility. Further reduction in VT is obtained by using copolymers and blends of PMMA and dimethylamino ethyl methacrylate (DMAEMA)-containing polymers, where a higher molar fraction of DMAEMA leads to a consistent drop in VT to -0.7 V. The electron-donating groups of the tertiary amines in the DMAEMA show clear interfacial doping of the semiconductor, reducing the voltage required to populate the dielectric/semiconductor interface with charge carriers and turn on the device. Blending trace amounts of DMAEMA-containing copolymers with PMMA proves to be an effective strategy for reducing the VT while keeping the charge mobility high, unlike when using pure copolymers with elevated DMAEMA content. Time of flight secondary ion mass spectroscopy (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) demonstrate that the DMAEMA-containing copolymer is floating to the surface of the PMMA blend at the dielectric–semiconductor interface, which explains the reduced VT. Synchrotron scanning transmission X-ray microscopy (STXM) demonstrates that PMMA promotes a more edge-on orientation of F10-SiPc films, compared to the more face-on orientation when deposited on the DMAEMA containing copolymer. This study demonstrates a straightforward process for designing dielectric polymers and their blends for the reduction in VT for n-type OTFTs.
Glycoside Phosphorylase Catalyzed Cellulose and β-1,3-Glucan Synthesis Using Chromophoric Glycosyl Acceptors
(American Chemical Society, 2024-08-12) Pylkkänen, Robert; Maaheimo, Hannu; Liljeström, Ville; Mohammadi, Pezhman; Penttilä, Merja; Department of Bioproducts and Biosystems; Department of Applied Physics; OtaNano; Synthetic Biology; VTT Technical Research Centre of Finland
Glycoside phosphorylases are enzymes that are frequently used for polysaccharide synthesis. Some of these enzymes have broad substrate specificity, enabling the synthesis of reducing-end-functionalized glucan chains. Here, we explore the potential of glycoside phosphorylases in synthesizing chromophore-conjugated polysaccharides using commercially available chromophoric model compounds as glycosyl acceptors. Specifically, we report cellulose and β-1,3-glucan synthesis using 2-nitrophenyl β-d-glucopyranoside, 4-nitrophenyl β-d-glucopyranoside, and 2-methoxy-4-(2-nitrovinyl)phenyl β-d-glucopyranoside with Clostridium thermocellum cellodextrin phosphorylase and Thermosipho africanus β-1,3-glucan phosphorylase as catalysts. We demonstrate activity for both enzymes with all assayed chromophoric acceptors and report the crystallization-driven precipitation and detailed structural characterization of the synthesized polysaccharides, i.e., their molar mass distributions and various structural parameters, such as morphology, fibril diameter, lamellar thickness, and crystal form. Our results provide insights for the studies of chromophore-conjugated low molecular weight polysaccharides, glycoside phosphorylases, and the hierarchical assembly of crystalline cellulose and β-1,3-glucan.
Edible and Biodegradable Wearable Capacitive Pressure Sensors: A Paradigm Shift toward Sustainable Electronics with Bio-Based Materials
(Wiley-VCH Verlag, 2024-08-08) Basarir, Fevzihan; Al Haj, Yazan; Zou, Fangxin; De, Swarnalok; Nguyen, An; Frey, Alexander; Haider, Ijlal; Sariola, Veikko; Vapaavuori, Jaana; Department of Chemistry and Materials Science; Department of Bioproducts and Biosystems; Multifunctional Materials Design; Microbial Physiology; Molecular biotechnology; Tampere University
This study presents a significant advancement in sustainable electronics, introducing an innovative capacitive-type wearable pressure sensor crafted entirely from edible and biodegradable biomaterials. The sensor's constituents, encompassing the substrate, electrode, and dielectric elements, are obtained using edible and renewable sources, specifically cellulose and pectin. Leveraging their non-metallic properties, these materials facilitate natural biodegradation, effectively reducing the environmental impact of electronic waste. Employing green chemistry principles during material preparation ensures the exclusion of critical raw materials. The resulting sensors showcase a versatile pressure detection range, from subtle pressures of 100 Pa to a maximum threshold of 100 kPa. Demonstrating a sensitivity of 0.0294 kPa−1 in the subtle pressure regime, the sensors exhibit a low detection limit of 10 Pa and a fast response time of 118 ms. The sensors exhibited notable repeatability and robustness, enduring over 10 000 loading-unloading cycles without succumbing to fatigue. Applied in real-time human motion detection, the sensors prove their potential applicability. In a biodegradability assessment, all sensor elements exhibit rapid degradation by various fungi, marking a significant stride toward a high-performance, edible, and wearable capacitive pressure sensor that can be deposited as biowaste at the end of its lifecycle.
In-situ biomethanation of high CO content syngas in agricultural biogas digesters
(Elsevier Ltd, 2024-10) Kamravamanesh, Donya; Rinta-Kanto, Johanna M.; Myllärinen, Antti; Saalasti, Mikko; Rintala, Jukka; Kokko, Marika; Department of Bioproducts and Biosystems; Tampere University; Doranova Oy
To meet global energy demands, syngas with high CO content (>50 %) generated from hydrothermal gasification of agricultural residues or wood, could be utilized as a co-substrate in anaerobic digestion (AD) processes for conversion into CH4. This study investigated in-situ biomethanation using synthetic gas (55 % CO, 35 % H2, and 15 % CO2), mimicking wood gasification syngas, during AD of cow manure, the most abundant agricultural waste. A continuously stirred tank reactor (CSTR) served as a control and was fed only cow manure, while the other two reactors were fed syngas with or without gas recirculation at different gas loading rates (GLRs). In-situ syngas injection in AD of cow manure at GLRs ≤0.3 L LRV−1 d−1 improved overall CH4 productivity compared to the control (0.35 ± 0.1 vs. 0.29 ± 0.1 L LRV−1 d−1), though the CH4 content (45 ± 5 %) was lower than the control reactor (62 ± 3 %), indicating a need for biogas upgrading. Gas recirculation enabled higher CO and H2 conversion efficiencies of 99–100 % but considerably decreased CH4 productivity from cow manure. In-situ biomethanation enhanced the relative abundance of hydrogenotrophic methanogens, highlighting their role in syngas conversion to CH4.
Development and characterization of pomegranate peel extract-infused carboxymethyl cellulose composite films for functional, sustainable food packaging
(Elsevier Science Ltd., 2025-01) Baniasadi, Hossein; Fathi, Ziba; Lizundia, Erlantz; Cruz, Cristina D.; Abidnejad, Roozbeh; Fazeli, Mahyar; Tammela, Päivi; Kontturi, Eero; Lipponen, Juha; Niskanen, Jukka; Department of Chemical and Metallurgical Engineering; Department of Bioproducts and Biosystems; Polymer Synthesis Technology; Bioproduct Technology; Materials Chemistry of Cellulose; University of the Basque Country; University of Helsinki
Our study explores the development and characterization of carboxymethyl cellulose (CMC)-based composite films integrated with clay particles and pomegranate peel extract (PE), aiming to inspire the films with natural antimicrobial and antioxidant properties for potential applications in food packaging. We conducted a comprehensive examination of the mechanical, barrier, surface, and degradation properties of these composite films, considering the impacts of incorporating clay particles and PE on their overall performance. Our findings reveal that the inclusion of clay particles enhances the mechanical strength and barrier properties of the films, while PE contributes to antioxidant and antibacterial effects. Namely, after the integration of 3 wt% clay, the tensile strength exhibited a remarkable increase of approximately 300%, accompanied by a notable reduction of 60% in water vapor permeability and 30% in oxygen transmission rate. Furthermore, the integration of PE into CMC films promoted antibacterial activity against 2 g-positive bacterial species, Staphylococcus aureus and Listeria monocytogenes. Additionally, we conducted a life cycle assessment (LCA) to quantify the cradle-to-gate environmental impacts of the developed bio-based active films. When normalized to the functional properties of the films, including mechanical and barrier performance, we observed significant benefits, with reductions of up to 59% after the concurrent incorporation of PE and clay nanosheets. Overall, our study underscores the potential of CMC-based composite films augmented with PE as a promising solution for sustainable food packaging, offering enhanced functionality while reducing environmental impact and increasing food safety.
The effect of the pyrolysis temperature and biomass type on the biocarbons characteristics
(Wiley-VCH Verlag, 2024-04-22) Iurchenkova, Anna; Kobets, Anna; Ahaliabadeh, Zahra; Kozir, Janez; Laakso, Ekaterina; Virtanen, Tommi; Siipola, Virpi; Lahtinen, Jouko; Kallio, Tanja; Department of Chemistry and Materials Science; Department of Applied Physics; Electrochemical Energy Conversion; Surface Science; Uppsala University; VTT Technical Research Centre of Finland
The conversion of biomass and natural wastes into carbon-based materials for various applications such as catalysts and energy-related materials is a fascinating and sustainable approach emerged during recent years. Precursor nature and characteristics are complex, hence, their effect on the properties of resulting materials is still unclear. In this work, we have investigated the effect of different precursors and pyrolysis temperature on the properties of produced carbon materials and their potential application as negative electrode materials in Li-ion batteries. Three biomasses, lignocellulosic brewery spent grain from a local brewery, catechol-rich lignin and tannins, were selected for investigations. We show that such end-product carbon characteristic as functional and elemental composition, porosity, specific surface area, defectiveness level, and morphology strictly depend on the precursor composition, chemical structure, and pyrolysis temperature. The electrochemical characteristics of produced carbon materials correlate with the characteristics of the produced materials. A higher pyrolysis temperature is shown to be favourable for production of carbon material for the Li-ion battery application in terms of both specific capacity and long-term cycling stability.
Incorporation of Nano-Zinc Oxide as a Strategy to Improve the Barrier Properties of Biopolymer–Suberinic Acid Residues Films: A Preliminary Study
(MDPI AG, 2024-08-05) Jeżo, Aleksandra; Poohphajai, Faksawat; Herrera Diaz, Rene; Kowaluk, Grzegorz; Department of Bioproducts and Biosystems; Warsaw University of Life Sciences; InnoRenew CoE
Finishing coatings in the wood-based composites industry not only influence the final appearance of the product but also serve to protect against fungi and molds and reduce the release of harmful substances, particularly formaldehyde and volatile organic compounds (VOCs). Carbon-rich materials, such as those derived from birch bark extraction, specifically suberin acids, can fulfill this role. Previous research has demonstrated that adding suberin acid residues (SAR) at 20% and 50% by weight significantly enhances the gas barrier properties of surface-finishing materials based on poly(lactide) (PLA) and polycaprolactone (PCL), particularly in terms of total VOC (TVOC) and formaldehyde emissions. This study aims to explore whether these properties can be further improved through the incorporation of nano-zinc oxide (nano-ZnO). Previous research has shown that these nanoparticles possess strong resistance to biological factors and can positively affect the characteristics of nanofilms applied as surface protection. The study employed PLA and PCL finishing layers blended with SAR powder at 10% w/w and included 2% and 4% nano-zinc oxide nanoparticles. The resulting blends were milled to create a powder, which was subsequently pressed into 1 mm-thick films. These films were then applied to raw particleboard surfaces. TVOC and formaldehyde emission tests were conducted. Additionally, the fungal resistance of the coated surfaces was assessed. The results showed that PLA/SAR and PCL/SAR composites with the addition of nano-zinc oxide nanoparticles exhibited significantly improved barrier properties, offering a promising avenue for developing biodegradable, formaldehyde-free coatings with enhanced features in the furniture industry. Furthermore, by utilizing SAR as a post-extraction residue, this project aligns perfectly with the concept of upcycling.
Thermal Degradation and Chemical Analysis of Flame-Retardant-Treated Jute Fabrics
(MDPI AG, 2024-07-18) Begum, Most Setara; Hummel, Michael; Mandal, Sumit; Mahmood, Shahriare; Repon, Md Reazuddin; Milašius, Rimvydas; Department of Bioproducts and Biosystems; Biopolymer Chemistry and Engineering; Kaunas University of Technology; Oklahoma State University; University of Oulu
Jute is an inherent lignocellulosic fiber, consisting of hemicellulose, α-cellulose, and lignin. Industrial ventilation, automotive composites, upholstery, carpets, military uniforms, hospital furnishings, and curtains necessitate the integration of flame-retardance properties into jute fibers. In this investigation, seven weave-structured jute fabrics were treated using an organophosphorus-based flame-retardant (FR) chemical (ITOFLAM CPN) and a crosslinking agent (KNITTEX CHN) by the pad–dry–cure method. The thermal stability, degradation and pyrolysis behavior of jute was measured using a thermogravimetric analyzer (TGA). Surface morphology and element distribution were scrutinized utilizing a scanning electron microscope (SEM) and an energy-dispersive spectrometer (EDS). The ATR-FTIR (Attenuated Total Reflection-Fourier Transform Infrared Spectrometer) technique has been employed for analyzing the composition of chemicals in the jute fabrics. According to the protocols specified in ISO 14184-1, free formaldehyde detection was carried out on the jute fabrics. The flame-retardance property was significantly improved on all of the jute fabrics after FR treatment. FTIR and SEM-EDS studies revealed the presence of FR chemical deposition on the surface of the jute fabrics. TGA analysis indicated that the fabrics treated with FR exhibited premature degradation, leading to the generation of more char compared to untreated samples. The jute fabrics specifically demonstrated a notable enhancement in residual mass, exceeding 50% after FR treatment. However, it is noteworthy that the FR-treated fabrics exhibited an elevated level of free formaldehyde content, surpassing the permissible limit of formaldehyde in textiles intended for direct skin contact. The residual mass loss percentage after ten washes of FR-treated fabrics remained in a range from 32% to 36%. Twill weave designed fabrics (FRD4 and FRD5) clearly showed a lower thermal degradation temperature than the other weaves used in this study.
Weathering of Wood Modified with Acetic Anhydride—Physical, Chemical, and Aesthetical Evaluation
(MDPI AG, 2024-07) Sandak, Anna; Gordobil, Oihana; Poohphajai, Faksawat; Herrera Diaz, Rene; Department of Bioproducts and Biosystems; InnoRenew CoE; University of the Basque Country
The goal of this study is to comprehensively evaluate the natural weathering performance of three wood species representing hardwood and softwood modified with the acetylation process. Alder (Alnus glutinosa L.), beech (Fagus sylvatica L.), and radiata pine (Pinus radiata D. Don) were characterised by various techniques to determine the aesthetical, chemical, and physical changes. The overall aesthetic performance of the investigated species was similar, with all showing a change in appearance after 9 months of exposure. However, the multi-sensor approach used for characterisation revealed differences in weathering behaviour related to surface erosion, wettability, and changes in chemical composition between the investigated species. An increase in the surface roughness observed for both hardwoods was associated with the erosion of the wood surface and the leaching of photodegraded chemical components. On the contrary, values of Sa remained relatively constant for acetylated radiata pine. Acetylated pine wood exhibited lower susceptibility to bleaching at the initial stage of the weathering process (3 months) and represented a more constant CIE L* compared to the investigated hardwood species. The contact angle measured with water gradually decreased in the case of acetylated radiata pine for up to six months, then it plateaued with a slight oscillation around 15°. For both hardwood species, the big drop was observed already after three months, followed by rather similar values. The PCA of IR spectra highlighted different mechanisms in the weathering of acetylated softwood and hardwood. The acetylated hardwood samples showed higher thermal stability than acetylated radiata pine. Experimental findings provide a comprehensive understanding of the long-term performance of acetylated wood, which directly influences its practical applications by enhancing design strategies, maintenance planning, product development, market acceptance, and overall sustainability. Performed tests have demonstrated the potential of underutilised hardwood species, enhanced through the acetylation process, to serve as alternative cladding materials to commonly used acetylated radiata pine.
Electrochemical reduction of CO2 on a CoTPP/MWCNT composite: Investigation of operation parameters influence on CH3OH production by differential electrochemical mass spectrometry (DEMS)
(Elsevier Ltd, 2024-10) Hossain, Md Noor; Suominen, Milla; Kallio, Tanja; Department of Chemistry and Materials Science; Electrochemical Energy Conversion
Renewable electricity-driven electrochemical production of small organic molecules, such as CH3OH, from chemical industry waste CO2 feedstock is highly desirable for circular economy. These reactions proceed via multiple intermediate steps which causes high overpotential and poor selectivity imposing a challenge for designing techno-economically viable systems. Proper understanding of the reaction mechanism is essential to overcome those challenges. Herein, we present a simple qualitative analysis to understand the reaction mechanism during electrochemical reduction of CO2 (eCO2R) on a cobalt tetraphenylporphyrin / multiwalled carbon nanotube (CoTPP/MWCNT) composite in the temperature range of 20–50 °C by employing differential electrochemical mass spectrometry (DEMS) in 0.1 M and 0.5 M KHCO3 electrolytes. Interestingly, temperature is observed to strongly affect the onset potentials for product generation in such a way that with the increase of temperature from 20 °C to 50 °C a decrease in the onset potential specifically for methanol formation is observed. Moreover, formaldehyde (HCHO) formation appears to occur at lower overpotentials before the formation of CH3OH which suggests that on the composite electrocatalyst, HCHO is an important intermediate on a route to CH3OH. This work offers valuable information on reaction routes to CH3OH and temperature effects on the eCO2R selectivity on molecular catalysts.
A Binder-Free Nickel-Rich Cathode Composite Utilizing Low-Bundled Single-Walled Carbon Nanotubes
(Wiley-VCH Verlag, 2024-07-22) Mousavihashemi, Seyedabolfazl; Khabushev, Eldar M.; Lahtinen, Jouko; Bogdanova, Alisa R.; Novikov, Ilya V.; Krasnikov, Dmitry V.; Nasibulin, Albert G.; Kallio, Tanja; Department of Chemistry and Materials Science; Department of Applied Physics; Electrochemical Energy Conversion; Surface Science
In this study, the performance of a binder-free LiNi0.6Co0.2Mn0.2O2 (NMC622) positive electrode utilizing single-walled carbon nanotubes (SWCNTs) is investigated and compared to the conventional state-of-the-art NMC622 composite positive electrode. The binder-free electrode has been prepared without using toxic and expensive N-Methyl-2-pyrrolidone (NMP) solvent and it is free-standing that allows a wider range of applications such as flexible devices. Electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge reveal that the binder-free positive electrode performance is similar to the conventional composite cathodes, deducing that only ≈1% of SWCNTs perform well not only as a conductive agent but also as a binder. The NMC622 composite electrode with SWCNTs provided specific capacity of 135.8 mAh g−1 at a 5C rate during discharge, with above 97% capacity retention after the rate capability test in a half cell.
Scanning WAXS microscopy of regenerated cellulose fibers at mesoscopic resolution
(International Union of Crystallography, 2024-07-01) Johansson, Sara; Scattarella, Francesco; Kalbfleisch, Sebastian; Johansson, Ulf; Ward, Christopher; Hetherington, Crispin; Sixta, Herbert; Hall, Stephen; Giannini, Cinzia; Olsson, Ulf; Department of Bioproducts and Biosystems; Lund University; National Research Council of Italy
In this work, regenerated cellulose textile fibers, Ioncell-F, dry-wet spun with different draw ratios, have been investigated by scanning wide-Angle X-ray scattering (WAXS) using a mesoscopic X-ray beam. The fibers were found to be homogeneous on the 500nm length scale. Analysis of the azimuthal angular dependence of a crystalline Bragg spot intensity revealed a radial dependence of the degree of orientation of crystallites that was found to increase with the distance from the center of the fiber. We attribute this to radial velocity gradients during the extrusion of the spin dope and the early stage of drawing. On the other hand, the fiber crystallinity was found to be essentially homogeneous over the fiber cross section.
Structural stability of DNA origami nanostructures in organic solvents
(Royal Society of Chemistry, 2024-07-28) Enlund, Eeva; Julin, Sofia; Linko, Veikko; Kostiainen, Mauri A.; Department of Bioproducts and Biosystems; Center of Excellence in Life-Inspired Hybrid Materials, LIBER; Biohybrid Materials
DNA origami nanostructures have attracted significant attention as an innovative tool in a variety of research areas, spanning from nanophotonics to bottom-up nanofabrication. However, the use of DNA origami is often restricted by their rather limited structural stability in application-specific conditions. The structural integrity of DNA origami is known to be superstructure-dependent, and the integrity is influenced by various external factors, for example cation concentration, temperature, and presence of nucleases. Given the necessity to functionalize DNA origami also with non-water-soluble entities, it is important to acquire knowledge of the structural stability of DNA origami in various organic solvents. Therefore, we herein systematically investigate the post-folding DNA origami stability in a variety of polar, water-miscible solvents, including acetone, ethanol, DMF, and DMSO. Our results suggest that the structural integrity of DNA origami in organic solvents is both superstructure-dependent and dependent on the properties of the organic solvent. In addition, DNA origami are generally more resistant to added organic solvents in folding buffer compared to that in deionized water. DNA origami stability can be maintained in up to 25–40% DMF or DMSO and up to 70–90% acetone or ethanol, with the highest overall stability observed in acetone. By rationally selecting both the DNA origami design and the solvent, the DNA origami stability can be maintained in high concentrations of organic solvents, which paves the way for more extensive use of non-water-soluble compounds for DNA origami functionalization and complexation.

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