Browsing by Author "Fang, Wenwen"

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  • Acid hydrolysis of cotton to adjust molar mass and viscosity
    (2024-12-23) Ly, Violet
     Kemiantekniikan korkeakoulu | Bachelor's thesis
    Cotton is a very common natural fiber, typically used in various clothing and household textiles. With the growing global population, the demand for textiles is increasing, leading to a rapid intensification of textile production. As a result, fast fashion has become more widespread, where textiles are neither produced to be durable nor recycled. The textile industry is notoriously one of the largest contributors to environmental emissions worldwide. The industry generates significant amounts of textile waste, and efforts are being made to address this issue by developing efficient recycling processes. Recycling cotton is particularly valuable because its cultivation requires large amounts of water and pesticides, which are harmful to the environment. However, recycling cotton fibers is highly challenging due to their broad molar mass distribution and high viscosity. This challenge can be partially addressed by using acid hydrolysis as a pretreatment method before recycling cotton fibers. The objective of this bachelor's thesis was to investigate how acid hydrolysis affects the molecular mass and viscosity of cotton cellulose fibers using the Ioncell technology. This research aims to alleviate the burden of textile waste by enhancing the recycling of cotton fibers. The thesis examined the environmental and sustainability challenges associated with cotton, as well as the methods developed to address these issues. Additionally, it focused on the mechanical and chemical properties of cotton and the various manmade cellulosic fiber processing methods, particularly the novel ioncell process, relevant to this. In the experimental part of the thesis, post-consumer cotton was used as the material, which was milled into cotton pulp. Sulfuric acid, diluted to the desired concentration, was employed as the acid solvent for acid hydrolysis. The molecular mass of cotton was measured using gel permeation chromatography (GPC), and intrinsic viscosity measurement was utilized to assess the viscosity. The results of the study showed that acid hydrolysis reduced the molecular mass of cotton over time. This was clearly evident in the gel permeation chromatography measurements coupled with the decreasing intrinsic viscosity over hydrolysis time. Based on this research, it is recommended that further studies test latter steps of the ioncell process using these pretreated cotton fibers.
  • Characterization and drug delivery of AaltoCell™ microcrystalline cellulose
    (2018-04-03) Dong, Yujiao
     Kemian tekniikan korkeakoulu | Master's thesis
    Microcrystalline cellulose (MCC) is widely utilized in various fields, such as food, pharmaceutics, medicine, and cosmetics. As such an important component, MCC has been deeply studied during recent decades. In this thesis, studies focused on AaltoCell™ MCC, which has been manufactured by a novel AaltoCell™ method. This method is more environmentally friendly than the traditional manufacturing methods, which makes this MCC worthy to be researched for applications. The main tasks of this thesis were characterizing rheological properties of different grades of AaltoCell™ MCC and applying them in controlled drug delivery system as the matrix material. As comparison, a commercial grade of MCC, Avicel® PH-101 was studied. Three types of rheological experiments were conducted to AaltoCell™ MCC, oscillatory stress sweep, frequency sweep, and dynamic viscosity measurement. In the drug release experiments, metronidazole and lysozyme were used as model compounds whose release rates form the gel-like AaltoCell™ matrices were studied. The results of the rheological experiments indicate that rheological properties strongly depend on the concentration of AaltoCell™ MCC, which means that with increasing the concentration, the rheological properties are significantly increased. The results of the drug release experiments indicate that AaltoCell™ MCC could efficiently control diffusion of both large and small molecule which shows great potential for a drug delivery application. In further study, the release profiles of other compounds and effect of concentration on the release profiles could be studied.
  • Coacervation of resilin fusion proteins containing terminal functionalities
    (2018-11-01) Fang, Wenwen; Nonappa; Vitikainen, Marika; Mohammadi, Pezhman; Koskela, Salla; Soikkeli, Miika; Westerholm-Parvinen, Ann; Landowski, Christopher P.; Penttilä, Merja; Linder, Markus B.; Laaksonen, Päivi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Liquid-liquid phase transition known as coacervation of resilin-like-peptide fusion proteins containing different terminal domains were investigated. Two different modular proteins were designed and produced and their behavior were compared to a resilin-like-peptide without terminal domains. The size of the particle-like coacervates was modulated by the protein concentration, pH and temperature. The morphology and three-dimensional (3D) structural details of the coacervate particles were investigated by cryogenic transmission electron microscopy (cryo-TEM) and tomography (cryo-ET) reconstruction. Selective adhesion of the coacervates on cellulose and graphene surfaces was demonstrated.
  • Elastic and pH-Responsive Hybrid Interfaces Created with Engineered Resilin and Nanocellulose
    (2017-06) Fang, Wenwen; Paananen, Arja; Vitikainen, Marika; Koskela, Salla; Westerholm-Parvinen, Ann; Joensuu, Jussi J.; Landowski, Christopher P.; Penttilä, Merja; Linder, Markus; Laaksonen, Päivi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We investigated how a genetically engineered resilin fusion protein modifies cellulose surfaces. We characterized the pH-responsive behavior of a resilin-like polypeptide (RLP) having terminal cellulose binding modules (CBM) and showed its binding to cellulose nanofibrils (CNF). Characterization of the resilin fusion protein at different pHs revealed substantial conformational changes of the protein, which were observed as swelling and contraction of the protein layer bound to the nanocellulose surface. In addition, we showed that employment of the modified resilin in cellulose hydrogel and nanopaper increased their modulus of stiffness through a cross-linking effect.
  • Entangled and colloidally stable microcrystalline cellulose matrices in controlled drug release
    (2018-09-05) Dong, Yujiao; Paukkonen, Heli; Fang, Wenwen; Kontturi, Eero; Laaksonen, Timo; Laaksonen, Päivi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Drug release from a new type of matrix material consisting of partially fibrillated microcrystalline cellulose was investigated. A mechanical treatment of novel AaltoCell™ cellulose microcrystals caused partial opening of the nanofibrillary structure of the cellulose particles and entanglement of individual particles led into formation of an elastic network of microcrystalline cellulose. The rheological properties of the stable hydrogel-like materials were characterised by shear rheometry. Model compounds metronidazole and lysozyme were successfully employed in drug release experiments carried out by delignified (bleached) and lignin-containing matrices. The viscosity as well as the lignin-content played a role in the release dynamics of the drugs. Microcrystalline AaltoCell™ was proven as high-performing material for diffusion controlled release of the chosen model compounds and can be seen as a safe and economical alternative for novel matrix materials such as nanocellulose or cellulose derivatives.
  • Evaluating the Hydrothermal Stability of Superbase-Based Ionic Liquids in Cellulose Fiber Spinning
    (2024-10-15) Fang, Wenwen; Schlapp-Hackl, Inge; Hummel, Michael; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This study highlights the substantially improved hydrothermal stability of 7-methyl-1,5,7-triazabicyclo[4.4.0] dec-5-enium [mTBDH]+ in [mTBDH][MeOCH2COO] compared to [mTBDH][OAc], as well as the strong cellulose dissolution capability of [mTBDH][MeOCH2COO] and excellent spinnability with a maximum draw ratio of 14. These findings demonstrate the high potential of using [mTBDH][MeOCH2COO] as the solvent to advance Ioncell fiber spinning technology by reducing the hydrolysis rate of [mTBDH]+, thereby minimizing loss during solvent recycling processes.
  • Nanocellulose for bio-inspired nanocomposites - surface modification with recombinant proteins
    (2018) Fang, Wenwen
     School of Chemical Engineering | Doctoral dissertation (article-based)
    The increased concern about the environment and legislation pressure, such as plastic bag ban, has generated the fast-grown demand for renewable and sustainable materials to replace the petroleum-based products. Cellulose is the most abundant natural polymer on earth, which can be found in many different organisms ranging from microbes to plants and animals. Nanocellulose, including cellulose nanofibrils and cellulose nanocrystals, can be extracted from plant cell wall by mechanical treatment or acid hydrolysis. Due to its extraordinary mechanical properties, low density and good biocompatibility, nanocellulose attracts increasing interests for materials scientist. In this work, we used genetically engineered recombinant proteins containing multiple functional domains to functionalize nanocellulose and make nanocomposites together with other building components. First, we needed to understand how the proteins interact with nanocellulose. The cellulose binding domains were coupled with gold nanoparticles through EDC-NHS chemistry and their binding to nanocellulose was visualized with electron microscopy. Further, the in situ interaction of recombinant protein and nanocellulose surface was investigated with QCM-D. It showed that the recombinant proteins containing resilin like polypeptide and cellulose binding module could bind to cellulose surface and form a pH responsive layer. From the rheology study, we also found that the recombinant protein could cross-link the cellulose nanofibrils. This finding led to our next study, improve the mechanical properties of nanocellulose film by cross linking the fibrils with cellulose binding proteins. The stiffness of the cellulose film was clearly increased due to the cross-linking of fibrils. In order to make conductive cellulose film, carbon nanotubes were added to the cellulose matrix. A bifunctional protein containing a hydrophobic patch and a glycosylated domain was used to disperse carbon nanotube into the cellulose matrix. In addition, the protein-protein interaction was also investigated in this work. The recombinant protein contains resilin like polypeptides could form salt induced coacervates. The effect of ionic strength, pH, protein concentration and different termimal domains were studied with dynamic light scattering and electron microscopies. In conclusion, we demonstrated that genetically engineered proteins provide a new toolbox for the functionalization of nanocellulose and modify the interface between different building components in nanocomposites.
  • Optimization of Dry-Jet Wet Spinning of Regenerated Cellulose Fibers Using [mTBDH][OAc] as a Solvent
    (2023-09-19) Fang, Wenwen; Lim, E Yee; Nieminen, Kaarlo; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Superbase-based ionic liquids (ILs) have demonstrated excellent dissolution capability for cellulose, and employing the dry-jet wet spinning process, high-tenacity regenerated textile fibers have been made. Among a range of superbase-based ILs, [mTBDH][OAc] exhibited not only good spinnability but also exceptional recyclability, making it highly suitable for a closed-loop production of regenerated cellulose fibers. To further optimize the spinning process, we investigated the influence of the cellulosic raw materials and the IL with residual water on spinnability and fiber properties. In addition, single-filament spinning and multifilament spinning using spinnerets with different hole densities were investigated to reveal the upscaling challenges of the dry-jet wet spinning process. The air gap conditions, for example, temperature and moisture concentration were simulated using COMSOL multiphysics. The results indicate that the presence of a small amount of water (3 wt%) in the IL has a positive effect on spinnability, while the mechanical properties of the fibers remain unchanged.
  • Optimization of IONCELL spinning process using a recyclable superbase-based ionic liquid
    (2022-01-18) Lim, E
     Kemian tekniikan korkeakoulu | Master's thesis
  • Photoluminescent Nanocellulosic Film for Selective Hg2+ Ion Detection
    (2024-06-03) Sun, Jing; Fang, Wenwen; Liza, Afroza Akter; Gao, Rui; Song, Junlong; Guo, Jiaqi; Rojas, Orlando J.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We developed a highly sensitive solid-state sensor for mercury detection by stabilizing red-sub-nanometric fluorescent gold nanoclusters (AuNC, 0.9 ± 0.1 nm diameter) with bovine serum albumin in a matrix composed of cellulose nanofibrils (CNF) (BSA-AuNC/CNF). The main morphological and optical features of the system were investigated via atomic force/transmission electron microscopy and UV-Vis/fluorescence spectroscopy. The hybrid film (off-white and highly transparent) showed strong photoluminescene under UV irradiation. The latter is assigned to the AuNC, which also increase the ductility of the emitting film, which was demonstrated for high sensitivity Hg2+ detection. When used as a sensor system, following AuNC printing on CNF hybrid films, a limit of detection <10 nM was confirmed. What is more, nanocellulose films have a high pore structure and selective separation properties, showcasing a wide range of potential applications in many fields such as water treatment and oil–water separation.
  • Production and characterization of Ioncell® fibers from paper-grade pulps
    (2024-06-11) Räisänen, Essi
     Kemian tekniikan korkeakoulu | Master's thesis
    The increasing need for more sustainable textiles to replace fossil-based textiles, such as polyester and water-intensive cotton production, has resulted in new innovative methods to produce man-made cellulose fibers (MMCF). Ioncell® technology utilizes superbase-based ionic liquids (IL) as cellulose solvents for spinning solution (dope) formation that is dry-jet wet spun to form Ioncell® fibers. In this work, eucalyptus, and pine kraft pulps are dissolved into the ionic liquid [mTBDH][OAc]. Successful Ioncell® spinning requires a constant intrinsic viscosity of the pulp in the range of 420 to 500 mL·g-1. Since paper-grade pulps have a significantly higher intrinsic viscosity, a controlled adjustment of the intrinsic viscosity, expressed as the degree of polymerization (DPv), is required as a pretreatment in this target range. The DP adjustment is conducted by acid hydrolysis in 0.1 M sulfuric acid at 80 °C and a duration determined by preliminary kinetic tests. Spinning dopes are produced from both untreated and DP-adjusted pulps. The rheological examination of the dopes shows optimum viscoelastic behavior for the spinning dopes produced from the DP-adjusted pulps. Successful spinning is achieved in two different scales, in single filament spin-ning and multifilament spinning with 200 holes. The fibers resulting from multifilament spinning have superior strength properties compared to other commercial regenerated fibers with a tenacity of around 45 cN·tex-1 and a linear density of 1.6 dtex, which is achieved with a draw ratio (DR) of 8. The produced fibers are spun into Ioncell® yarn and knitted into a textile fabric.
  • Production of uv-sensitive textile fibres with the Ioncell® technology
    (2021-06-15) Sairanen, Emma
     Kemian tekniikan korkeakoulu | Master's thesis
    Ioncell® technology is a novel way of producing sustainable textiles, which is based on the production of cellulose-based fibres and yarns using ionic liquids as a green solvent. This technology enables the incorporation of functionalities directly into the fibre body while maintaining high mechanical properties, which opens avenues for smart textiles production. SensoGlow® is a non-toxic and tuneable mineral, which reacts to UV irradiation through a reversible colour change, i.e. photochromism. In this thesis, an environmentally friendly way of producing UV sensing textiles by incorporating SensoGlow® or a commercial photochromic dye into Ioncell® fibres was demonstrated. Incorporating additives into a cellulose dope while maintaining good spinnability is challenging, which is why it was crucial to develop a method that could disperse SensoGlow® particles homogeneously in ionic liquid and cellulose. In this work, both mechanical treatments (e.g. sonication) and dispersants (e.g. nanocellulose) were applied to improve the dispersion of SensoGlow®. After achieving a cellulose dope with evenly distributed SensoGlow® or dye, UV-sensitive fibres were successfully spun using a monofilament spinning unit. Lastly, multifilament spinning was used to produce SensoGlow® incorporated fibres, which were spun into yarn and knitted into a demo fabric. The results from the tensile testing showed that the incorporation of additives weakens the mechanical strength of fibres, but even with 5 wt% additive the tensile strength of fibres was similar to the commercial TencelTM. The results from the reflectance measurements indicated that the optical response of fibres is dependent on the additive concentration. Additionally, it was shown that 3.5% SensoGlow® fibres could be spun into yarn with similar tensile strength as TencelTM yarn and similar elongation as cotton yarn. Finally, 15 cm x 15 cm demo fabrics were knitted to demonstrate that 1) fabric with incorporated SensoGlow® can be used to detect UV exposure and 2) the fabric maintains functionality in normal wear. There is still room to optimize the process and enhance the fabric response to UV. However, as a proof-of-concept, this thesis implies that SensoGlow® can be incorporated into MMCFs to produce smart textiles that could be used to detect the UV dosage of the user.
  • StExCell: novel steam-explosion-based biorefinery concept for dissolving pulp production
    (2024-11-01) Lê, Huy Quang; She, Jialin; Fang, Wenwen; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    StExCell, a novel sulfur-free and chlorine-free biorefinery concept, based on mild steam explosion followed by mild caustic extraction, oxygen delignification and bleaching, is introduced to produce dissolving pulp for textile application. Steam explosion of Betula pendula at 210 °C for 7 isothermal min (equivalent to a P-factor of ca. 1,250), combined with a total-chlorine-free purification sequence resulted in a fully bleached pulp with only 3.6 % xylan, a slightly wider cellulose molar mass distribution and a higher pulp yield, while consuming only about half of the chemicals, in reference to a prehydrolysis-kraft process. The chemical recovery and valorization of the extracted wood component were not covered by the scope of this work but speculated to be simpler than in a kraft process.
  • Tuning the water interactions of cellulose nanofibril hydrogels using willow bark extract
    (2023-10-01) Huynh, Ngoc; Valle-Delgado, Juan José; Fang, Wenwen; Arola, Suvi; Österberg, Monika
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Cellulose nanofibrils (CNFs) are increasingly used as precursors for foams, films and composites, where water interactions are of great importance. In this study, we used willow bark extract (WBE), an underrated natural source of bioactive phenolic compounds, as a plant-based modifier for CNF hydrogels, without compromising their mechanical properties. We found that the introduction of WBE into both native, mechanically fibrillated CNFs and TEMPO-oxidized CNFs increased considerably the storage modulus of the hydrogels and reduced their swelling ratio in water up to 5–7 times. A detailed chemical analysis revealed that WBE is composed of several phenolic compounds in addition to potassium salts. Whereas the salt ions reduced the repulsion between fibrils and created denser CNF networks, the phenolic compounds - which adsorbed readily on the cellulose surfaces - played an important role in assisting the flowability of the hydrogels at high shear strains by reducing the flocculation tendency, often observed in pure and salt-containing CNFs, and contributed to the structural integrity of the CNF network in aqueous environment. Surprisingly, the willow bark extract exhibited hemolysis activity, which highlights the importance of more thorough investigations of biocompatibility of natural materials. WBE shows great potential for managing the water interactions of CNF-based products.
  • Upcycling of Keratin Wastes in Sustainable Textile Fiber Applications
    (2023-10-09) Fang, Wenwen; Fan, Ruxia; Aranko, A. Sesilja; Hummel, Michael; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The textile industry is facing growing pressure to adopt sustainable practices, including the development of biodegradable and recyclable fibers derived from waste streams. In this study, we explored the use of keratin from waste textiles as a potential raw material for sustainable fiber production. We investigated the dissolution of keratin in 7-methyl-1,5,7-triazabicyclo(4.4.0)dec-5-ene (mTBD)-based ionic liquids (ILs) and its regeneration in various coagulation solvents. The viscoelastic properties of the keratin solution were characterized using small angle oscillation shear rheology (SAOS), and the results showed that the keratin solution was not suitable for the dry-jet spinning process and the pure regenerated keratin fiber was too weak to hold the stretching in fiberline. To bypass these issues, we blended high molar mass cellulose with keratin during the dissolution step to adjust the rheological properties and mechanical strength of the extruded fibers. The resulting hybrid fibers exhibited high strength, low fibrillation tendency, and soft texture. We also demonstrated the further processability of these fibers by spinning a yarn and knitting a piece of fabric. Our findings suggest that hybrid fibers derived from keratin waste textiles and cellulose could be promising materials for sustainable fashion applications.
  • UV-Sensing Cellulose Fibers Manufactured by Direct Incorporation of Photochromic Minerals
    (2021-12-06) Fang, Wenwen; Sairanen, Emma; Vuori, Sami; Rissanen, Marja; Norrbo, Isabella; Lastusaari, Mika; Sixta, Herbert
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Textile-based wearable sensors integrated into daily wear offer opportunities for on-demand, real-time self-diagnosis to monitor health conditions with changing environmental surroundings and hazards. One still underrated environmental hazard is accumulated UV irradiation, causing skin burns, accelerated aging, and skin cancers. Here, we have demonstrated a sustainable fiber manufacture process to integrate photochromic hackmanite micro-particles directly into a cellulose body to achieve UV-sensing functionality in daily-life textiles. The hackmanite particles were dispersed into an ionic liquid cellulose dope using ultrasonication and nanofibrillated cellulose as a dispersant, resulting in good spinnability. The obtained fibers possess high mechanical strength with up to 10% photochromic hackmanite loading. To demonstrate its application in wearable UV sensors, the fibers were spun into yarn and then knitted into a piece of jersey fabric. The coloration of hackmanite-incorporated textiles under UV irradiation is readily quantified by image analysis using red-green-blue ratios, which was further utilized for UV dosimetry with a smartphone application showcasing the practical use of the UV sensor. The UV-sensing functionality remained the same after intensive washing and abrasion tests, further demonstrating the feasibility of its application in everyday garments.