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  • 1.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Henshaw Osong, Sinke
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Tai, Cheuk-Wai
    The Arrhenius Laboratory, Stockholm University.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Eco-friendly design for scalable direct fabrication of nanocelluloseManuscript (preprint) (Other academic)
  • 2.
    Afewerki, Samson
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Tai, Cheuk-Wai
    The Arrhenius Laboratory, Stockholm University.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sustainable Design for the Direct Fabrication and Highly Versatile Functionalization of Nanocelluloses2017In: Global Challenges, ISSN 2056-6646, Vol. 1, no 7, article id 1700045Article in journal (Refereed)
    Abstract [en]

    This study describes a novel sustainable concept for the scalable direct fabrication and functionalization of nanocellulose from wood pulp with reduced energy consumption. A central concept is the use of metal-free small organic molecules as mediators and catalysts for the production and subsequent versatile surface engineering of the cellulosic nanomaterials via organocatalysis and click chemistry. Here, “organoclick” chemistry enables the selective functionalization of nanocelluloses with different organic molecules as well as the binding of palladium ions or nanoparticles. The nanocellulosic material is also shown to function as a sustainable support for heterogeneous catalysis in modern organic synthesis (e.g., Suzuki cross-coupling transformations in water). The reported strategy not only addresses obstacles and challenges for the future utilization of nanocellulose (e.g., low moisture resistance, the need for green chemistry, and energy-intensive production) but also enables new applications for nanocellulosic materials in different areas.

  • 3.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Abbaszad Rafi, Abdolrahim
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Cellulosic Materials: Sustainable Surface Engineering of Lignocellulose and Cellulose by Synergistic Combination of Metal-Free Catalysis and Polyelectrolyte Complexes2019In: Global Challenges, ISSN 2056-6646, Vol. 3, no 7, article id 1970071Article in journal (Refereed)
    Abstract [en]

    In article number 1900018 by Armando Cordova and co‐workers, the novel combination of metal‐free catalysis and renewable polyelectrolyte complexes leads to synergistic surface engineering of lignocellulose and cellulose fibers derived from wood. This sustainable strategy allows for improvement and introduction of important properties such as strength (up to 100% in Z‐strength), water resistance, and fluorescence to the renewable fibers and cellulosic materials under eco‐friendly conditions.

  • 4.
    Alimohammadzadeh, Rana
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Cordova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Scalable Improvement of the Strength Properties of Chemimechanical Pulp Fibers by Eco-Friendly Catalysis2018In: IMPC 2018, Trondheim, Norway, 2018Conference paper (Refereed)
    Abstract [en]

    The sustainable improvement of the strength properties of chemimechanical pulp by eco-friendlycatalysis is disclosed. Significant research activities have been performed on the use of cationic starchand polyelectrolyte complexes for improving the strength properties of cellulose-based materials. Herewe apply an eco-friendly strategy based on catalysis for significantly improving the strength propertiesof sheets made from chemimechanical pulp (CTMP) and bleeched sulphite pulp (BSP) using sustainablepolyelectrolyte complexes as the strength additives and organocatalysis. This surface engineeringstrategy significantly increased the strength properties of the assembled sheets (up to 100% in the caseof Z-strength). We also developed a catalytic selective colour marking of the cationic potato starch (CS)and carboxymethylcellulose (CMC) in order to elucidated how the specific strength additives aredistributed on the sheets. It revealed that the strength additives were more evenly distributed on thesheets made from CTMP as compared to BSP sheets. This is most likely attributed to the presence oflignin in the former lignocellulosic material. It also contributes to the increase in strength (up to 100%,Z-strength) for the CTMP derived sheets. The selective colour marking method also revealed that morestrength additives had been bound to the pulps in the presence of the catalyst.

  • 5.
    Cordova, Armando
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sanhueza, Italo
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Tai, Cheuk-Wai
    Stockholm University, Stockholm.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Ibrahem, Ismail
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    A sustainable strategy for production and functionalization of nanocelluloses2019In: Pure and Applied Chemistry, ISSN 0033-4545, E-ISSN 1365-3075, Vol. 91, no 5, p. 865-874Article in journal (Refereed)
    Abstract [en]

    A sustainable strategy for the neat production and surface functionalization of nanocellulose from wood pulp is disclosed. It is based on the combination of organocatalysis and click chemistry ("organoclick" chemistry) and starts with nanocellulose production by organic acid catalyzed hydrolysis and esterification of the pulp under neat conditions followed by homogenization. This nanocellulose fabrication route is scalable, reduces energy consumption and the organic acid can be efficiently recycled. Next, the surface is catalytically engineered by "organoclick" chemistry, which allows for selective and versatile attachment of different organic molecules (e.g. fluorescent probes, catalyst and pharmaceuticals). It also enables binding of metal ions and nanoparticles. This was exemplified by the fabrication of a heterogeneous nanocellulose-palladium nanoparticle catalyst, which is used for Suzuki cross-coupling transformations in water. The disclosed surface functionalization methodology is broad in scope and applicable to different nanocelluloses and cellulose based materials as well.

  • 6.
    Fiskari, Juha
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Valmet AB.
    Ferritsius, Rita
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering. Stora Enso Paper, Kvarnsvedens Mill.
    Osong, Sinke H.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Persson, Anders
    Valmet AB.
    Höglund, Tomas
    Valmet AB.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Deep Eutectic Solvent Treatment to Low-Energy TMP to Produce Fibers for Papermaking2018In: IMPC 2018, Trondheim, Norway, 2018Conference paper (Refereed)
    Abstract [en]

    The aim of this research was to gain a better understanding on whether a novel process based on low-energy thermo-mechanical pulp (TMP) process followed by a chemical treatment with deep eutectic solvents (DESs) could produce fibers suitable for papermaking. In full scale production, these fibers could be produced at a much lower capital and operational costs, especially when utilizing existing TMP plants which are under the threat to be shut down or have already been shut down due to a decreasing demand for newsprint and other wood-containing papers.The efficiency of several DES treatments under various temperatures and times were evaluated by carrying out experiments in standard Teflon-lined autoclaves. A few tests were also performed in a unique nonstandard flow extractor. Pulp samples were characterized for their cellulose, hemicellulose and lignin contents. Moreover, tensile index was measured both before and after pulp refining. Depending on the solvent, the response of mechanical pulp varied, especially in terms of hemicellulose dissolution. Lactic acid, oxalic acid and urea, all in combination with choline chloride ([Ch]Cl) as the hydrogen bond acceptor, dissolved about 50% of the lignin of the low-energy TMP fibers under the tested conditions. The mixture of malic acid and [Ch]Cl was less effective in lignin dissolution. The mixture of urea and [Ch]Cl exhibited only a minor loss in hemicellulose content, when compared to the other tested DESs. Although 50% of the lignin was dissolved with minor loss in hemicellulose no improvement in tensile strength was observed, as it was rather the opposite. Another benefit with the mixture of urea and [Ch]Cl was that this DES did not appear to be corrosive to stainless steel. All other tested DESs—which were also quite acidic—were observed to be corrosive. Moreover, this DES-related corrosion was found to intensify at elevated temperatures.When chips were used as starting material with otherwise the same conditions almost no lignin was dissolved. This suggests that low-energy mechanical pulp is likely to be a good starting material for extracting lignin using DESs.

  • 7.
    Henshaw Osong, Sinke
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Olin, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Development of CTMP-based nanofibrillated Cellulose /nanographite composites for paper applications2015Conference paper (Other academic)
  • 8.
    Henshaw Osong, Sinke
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    The use of cationic starch and microfibrillated cellulose to improve strength properties of CTMP-based paperboardManuscript (preprint) (Other academic)
  • 9.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    A New Concept to Produce Nano-ligno-cellulose Materials by Means of High Pressure Homogenization2012Conference paper (Refereed)
  • 10.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mechanical Properties of high-yield pulp handsheets, as affected by blends of Nano-ligno-cellulose2013Conference paper (Refereed)
  • 11.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    New Products based on Mechanical Pulps: Nano-ligno-cellulose (NLC)2013Conference paper (Refereed)
  • 12.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Nano-ligno-cellulose as strength enhancer in handsheets2013Conference paper (Other academic)
    Abstract [en]

    In recent years, there has been tremendous work in the research field of nanocellulose or microfibrillated cellulose but, very few scholars have envisioned the use of the low quality fibre fraction of mechanical pulps for the production of mechanical pulp based nanocellulose, referred to as nano-ligno-cellulose (NLC) in this paper. Today, it has been noticed by many that there has been an economic downturn in the pulp and paper industry and that this adverse situation could be somewhat alleviated by possibly searching for better products or by improving the material quality of existing products (papers and paperboards). This paper presents results related to paper strength properties based on testing of handsheets of pulp fibres blended with nanocellulose. The results indicate that the addition of nano-ligno-cellulose (NLC) to chemi-thermomechanical pulp (CTMP) fibres improved the z-strength property of laboratory sheets with only a slight effect in relation to the sheet density. Also the crill characterisation method was used to evaluate fibre size distribution. The measurement of crill is based on optical response of a suspension at two wavelengths of light; UV and IR. The UV light contains information on both the total fibres and the crill, while IR only contains information on fibres. Results showed that the crill value of NLC of CTMP correlated (linearly) fairly well with the homogenisation time.

  • 13.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Nano-ligno-cellulose from mechanical pulp fines2013Conference paper (Refereed)
  • 14.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Recent developments in nano-ligno-cellulose production and the crill characterization technique2014In: TAPPI International Conference on Nanotechnology for Renewable Materials 2014, TAPPI Press, 2014, p. 193-205Conference paper (Refereed)
  • 15.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lundberg, Mathias
    PulpEye AB Örnsköldsvik Sweden.
    Reza, Mehedi
    Aalto University, School of Science and Technology, Aalto, Finland.
    Tapani, Vuorinen
    Aalto University, School of Science and Technology, Aalto, Finland.
    Qualitative evaluation of microfibrillated cellulose usingthe crill method and some aspects of microscopy2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 6, p. 3611-3624Article in journal (Refereed)
    Abstract [en]

    It has been a challenge to develop rapid online characterisation techniques for nanocellulose given the fibrillar structure of the nanoparticles. The crill optical analyser uses optical response signals in the infrared (IR) and ultraviolet (UV) wavelength ranges to evaluate the particle size properties of micro/nanofibrillar cellulosic materials. In this work, the crill analyser was used to measure the projected areas of UV and IR light sources by measuring the light blocked by nanocellulosic particles. This work uses the crill methodology as a new, simplified technique to characterise the particle size distribution of nanocellulosic material based on chemi-thermomechanical pulp (CTMP), thermomechanical pulp (TMP), and sulphite pulp (SP). In the first part, hydrogen peroxide pretreatment of CTMP and TMP in a wing mill refiner followed by high-pressure homogenisation to produce microfibrillated cellulose (MFC) was evaluated using the crill method. In the second part, TEMPO oxidation of CTMP and SP combined with high-shear homogenisation to produce MFC was studied using the crill method. With 4 % hydrogen peroxide pretreatment, the crill values of the unhomogenised samples were 218 and 214 for the TMP and CTMP, respectively, improving to 234 and 229 after 18 homogenisation passes. The results of the TEMPO method indicated that, for the 5 mmol NaClO SP-MFC, the crill value was 108 units at 0 min and 355 units after 90 min of treatment, a 228 % improvement. The CTMP and TMP fibres and the MFC were freeze dried and fibrillar structure of the fibres and microfibrils was visualised using scanning electron and transmission electron microscopy.

  • 16.
    Osong, Sinke H.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Pettersson, Gunilla
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Còrdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Afewerki, Samson
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Alimohammadzadeh, Rana
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Processing of nanocellulose and applications relating to CTMP-based paperboard and foams2016In: International Mechanical Pulping Conference 2016, IMPC 2016, TAPPI Press, 2016, p. 87-93Conference paper (Refereed)
    Abstract [en]

    Although remarkable success has been made in the production of nanocellulose through several processing methods, it still remain a challenge to reduce the overall energy consumption, to use green chemistry and sustainable approach in order to make it feasible for industrial production of this novel nanomaterial. Herein, we have developed a new eco-friendly and sustainable approach to produce nanocellulose using organic acid combined with high-shear homogenisation, made hydrophobisation of nanocellulose and cross-linked the modified nanocellulosic material. Also, TEMPO-mediated oxidised nanocellulose was produced in order to compare the processing route with that of mild organic acid hydrolysis. Freeze-dried 3D structure of TEMPO-derived nanocellulose foam materials made fi-om bleached sulphite pulp and CTMP, respectively. Further, there is growing interest in using nanocellulose or microfibrillated cellulose (MFC) as an alternative paper sfrength additive in papermaking, and in using chemi-thermomechanical pulp (CTMP) with high freeness in producing CTMP-based paperboard with high bulk properties. To achieve greater strength improvement results, particularly for packaging paperboards, different proportions of cationic starch (CS) or MFC can be used to significantly improve the z-strength, with only a slight increase in sheet density. Research in this area is exploring CS or MFC as potential strength additives in CTMP-based paperboard, which is interesting from an industrial perspective. The mean grammage of the CTMP handsheets produced was approximately 150 g m~, and it was found that blending CTMP with CS or MFC yielded handsheets with significantly improved z-strength, tensile index, burst index and other strength properties at similar sheet densities.

  • 17.
    Osong, Sinke Henshaw
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Development of nanofibrillated cellulose/nanographite composites for paper applications2015In: TAPPI International Conference on Nanotechnology for Renewable Materials 2015, TAPPI Press, 2015, Vol. 1, p. 35-55Conference paper (Refereed)
  • 18.
    Osong, Sinke Henshaw
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Development of nanofibrillated cellulose/nanographite composites for paper applications2015In: Cellulose Materials Doctoral Students Summer Conference 2015 / [ed] Hauhio, Leena, Aalto University, Finland, 2015Conference paper (Refereed)
  • 19.
    Osong, Sinke Henshaw
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mechanical Pulp Based Nano-ligno-cellulose: Production, Characterisation and their Effect on Paper Properties2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Almost all research on biorefinery concepts are based on chemical pulping processes and ways of utilising lignin, hemicelluloses and extractives as well as a part of the remaining cellulose for production of nano materials in order to create more valuable products than today. Within the Forest as a Resource (FORE) research program at FSCN we are utilising the whole chain of unit processes from forestry to final products as paper and board, where the pulping process research focus on high yield process as TMP and CTMP. As these process solutions are preserving or only slightly changing the properties of the original wood polymers and extractives, the idea is to find high value adding products designed by nature.

    From an economic perspective, the production of nanocellulose from a chemical pulp is quite expensive as the pulp has to be either enzymatically (e.g. mono-component endoglucanase) pre-treated or chemically oxidised using the TEMPO (2,2,6,6 - tetramethyl-piperidine-1-oxil) - mediated oxidation method in order to make it possible to disrupt the fibres by means of homogenisation.

    In high yield pulping processes such as in TMP and CTMP, the idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nano-ligno-cellulose (NLC). The integration of a NLC unit process in a high yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and board grades. The intention of this research work was that, by using this concept, a knowledge base can be created so that it becomes possible to develop a low-cost production method for its implementation.

    In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenisation It seems possible to homogenise fine particles of thermo-mechanical pulp (1% w/v) to NLC. A correspond fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration.

    The objective presented in this work was to develop a methodology for producing mechanical pulp based NLC from fines fractions and to utilise this material as strength additives in paper and board grades. Laboratory sheets of CTMP and BKP, with addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities.

    The characterisation of the particle size distribution of NLC is both important and challenging and the crill methodology developed at Innventia (former STFI) already during the 1980s was tested to see if it would be both fast and reliable enough. The crill measurement technique is based on the optical responses of a micro/nano particle suspension at two wavelengths of light; UV and IR. The crill value of TMP and CTMP based nano-ligno-cellulose were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time.

  • 20.
    Osong, Sinke Henshaw
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Mechanical Pulp-Based Nanocellulose: Processing and applications relating to paper and paperboard, composite films, and foams2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with processing of nanocellulose originating from pulps, with focus on mechanical pulp fibres and fines fractions. The nanocellulose materials produced within this research project were tested for different purposes ranging from strength additives in paper and paperboard products, via composite films to foam materials. TAPPI (Technical Association of Pulp & Paper Industry) has recently suggested a standard terminology and nomenclature for nanocellulose materials (see paper I). In spite of that we have decided to use the terms nano-ligno-cellulose (NLC), microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and nanocellulose (NC) in this thesis . It is well-known that mainly chemical pulps are used as starting material in nanocellulose production. However, chemical pulps as bleached sulphite and bleached kraft are quite expensive. One more cost-effective alternative can be to use fibres or fines fractions from thermo-mechanical pulp (TMP) and chemi-thermomechanical pulp (CTMP).

     

    In paper II-IV, fractionation has been used to obtain fines fractions that can easily be mechanically treated using homogenisation. The idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nanocellulose. The integration of a nanocellulose unit process in a high-yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and paperboard grades.

     

    Paper III describes how to utilise the crill measurement technique as a tool for qualitative estimation of the amount of micro- and nano-material produced in a certain process. The crill values of TMP- and CTMP-based nanocelluloses were measured as a function of the homogenisation time. Results showed that the crill values of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. In Paper V pretreating methods, hydrogen peroxide and TEMPO are evaluated. Crill measurement showed that hydrogen peroxide pretreatment (1% and 4%) and mechanical treatment time did not improve fibrillation efficiency as much as expected. However, for TEMPO-oxidised nanocelluloses, the crill value significantly increased with both the TEMPO chemical treatment and mechanical treatment time. In paper V-VII TEMPO-mediated oxidation systems (TEMPO/NaBr/NaClO) are applied to these fibres (CTMP and Sulphite pulp) in order to swell them so that it becomes easy to disrupt the fibres into nanofibres with mechanical treatment.

     

    The demand for paperboard and other packaging materials are steadily increasing. Paper strength properties are crucial when the paperboard is to withstand high load. A solution that are investigated in papers IV and VI, is to use MFC as an alternative paper strength additive in papermaking. However, if one wish to target extremely higher strength improvement results, particularly for packaging paperboards, then it would be fair to use MFC or cationic starch (CS). In paper VI CS or TEMPO-based MFC was used to improve the strength properties of CTMP-based paperboard products. Results here indicate significant strength improvement with the use of different levels of CS (i.e., 20 and 10 kg t–1) and 5% MFC. The strengthening impact of 5% MFC was approximately equal to that of 10 kg t–1 of CS.

     

    In paper VII, NFC and nanographite (NG) was used when producing composite films with enhanced sheet-resistance and mechanical properties. The films produced being quite stable, flexible, and bendable. Realising this concept of NFC-NG composite film would create new possibilities for technological advancement in the area of high-yield pulp technology.  Finally, in paper VIII, a new processing method for nanocellulose is introduced  where an organic acid (i.e., formic acid) is used. This eco-friendly approach has shown to be successful, a nanocellulose with a uniform size distribution has been produced.

  • 21.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Dahlström, Christina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Forsberg, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Andres, Britta
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engström, Ann-Christine
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Nanofibrillated cellulose/nanographite composite films2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 4, p. 2487-2500Article in journal (Refereed)
    Abstract [en]

    Though research into nanofibrillated cellulose (NFC) has recently increased, few studies have considered co-utilising NFC and nanographite(NG) in composite films, and, it has, however been a challenge to use high-yield pulp fibres (mechanical pulps) to produce this nanofibrillar material. It is worth noting that there is a significant difference between chemical pulp fibres and high-yield pulp fibres, as the former is composed mainly of cellulose and has a yield of approximately 50 % while the latter is consist of cellulose, hemicellulose and lignin, and has a yield of approximately 90 %. NFC was produced by combining TEMPO (2,2,6,6-tetramethypiperidine-1-oxyl)-mediated oxidation with the mechanical shearing of chemi-thermomechanical pulp (CTMP) and sulphite pulp (SP); the NG was produced by mechanically exfoliating graphite. The different NaClO dosages in the TEMPO system differently oxidised the fibres, altering their fibrillation efficiency. NFC-NG films were produced by casting in a Petri dish. We examine the effect of NG on the sheet-resistance and mechanical properties of NFC films. Addition of 10 wt% NG to 90 wt% NFC of sample CC2 (5 mmol NaClO CTMP-NFC homogenised for 60 min) improved the sheet resistance, i.e. from that of an insulating pure NFC film to 180 Omega/sq. Further addition of 20 (CC3) and 25 wt% (CC4) of NG to 80 and 75 wt% respectively, lowered the sheet resistance to 17 and 9 Omega/sq, respectively. For the mechanical properties, we found that adding 10 wt% NG to 90 wt% NFC of sample HH2(5 mmol NaClO SP-NFC homogenised for 60 min) improved the tensile index by 28 %, tensile stiffness index by 20 %, and peak load by 28 %. The film's surface morphology was visualised using scanning electron microscopy, revealing the fibrillated structure of NFC and NG. This methodology yields NFC-NG films that are mechanically stable, bendable, and flexible.

  • 22.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    An approach to produce nano-ligno-cellulose from mechanical pulp fine materials2013In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, no 4, p. 472-479Article in journal (Refereed)
    Abstract [en]

    Mechanical pulping, also called high-yield pulping processes, are pulping systems where a great deal of effort is taken with regards to the fractionation in screens and cleaners as well as to optimize process conditions to refine the rejected fractions. The fraction that is rejected for further treatment can vary from 10 to 50% depending on process strategy and final product which can be from printing paper, writing paper, paperboard middle layer and tissue. In practice, it is common that approximately 10% of the pulp fibres and also a large part of the fines fraction have properties that are unsatisfactory in relation to the final products. Part of the less useful fines fraction could instead be used to produce nano-ligno-cellulose (NLC) of high value either in the main product or used for completely different purposes.

    In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenization. It seems possible to homogenize fine particles of thermo-mechanical pulp (1% w/v) to NLC. A corresponding fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. This fines (BKP) fraction was very difficult to homogenize at a higher concentration (1% w/v). An explanation for this could be that the BKP fines have much higher cellulose content and lower charge level compared to the fines fraction of the hemicellulose and lignin-rich TMP. Fibre length-weighteddistribution plays a vital role with respect to both pressure fluctuations and clogging during treatment in the homogenizing equipment.

     

  • 23.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Paper strength improvement by inclusion of nano-ligno-cellulose to Chemi-thermomechanical pulp2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 2, p. 309-316Article in journal (Refereed)
    Abstract [en]

    So far, chemical pulp fibres have been utilized as conventional stock materials for nanocellulose production. The main aim of this work is to use stock materials from mechanical or chemi-thermomechanical pulping process to produce lignin containing nanofibres, which are referred to as nano-ligno-cellulose (NLC) in this study. The present study shows the influence on handsheets of chemi-thermomechanical pulp (CTMP) fibres blended with NLC. For comparison reasons, nanocellulose (NC) from bleached kraft pulp (BKP) was produced in a similar approach as NLC. Both the NLC and the NC were blended with their respective pulp fibres and their corresponding handsheets properties were evaluated with respect to sheet density. It was found that the handsheets of pulp fibres blended with NLC/NC improved the mechanical properties of handsheets with only a slight effect in relation to the sheet density. Improvements in strength properties of handsheets such as z-strength, tensile index, tear index, burst index, E-modulus, strain at break, tensile stiffness, air resistance were observed.

  • 24.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Processing of wood-based microfibrillated cellulose and nanofibrillated cellulose, and applications relating to papermaking: a review2016In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 23, no 1, p. 93-123Article, review/survey (Refereed)
    Abstract [en]

    As an emerging cellulosic nanomaterial, microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) have shown enormous potential in the forest products industry. The forest products industry and academia are working together to realise the possibilities of commercializing MFC and NFC. However, there are still needs to improve the processing, characterisation and material properties of nanocellulose in order to realise its full potential. The annual number of research publications and patents on nanocellulose with respect to manufacturing, properties and applications is now up in the thousands, so it is of the utmost importance to review articles that endeavour to research on this explosive topic of cellulose nanomaterials. This review examines the past and current situation of wood-based MFC and NFC in relation to its processing and applications relating to papermaking.

  • 25.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lundberg, M.
    PulpEye AB, Box 279, SE-891 26 Örnsköldsvik, Sweden.
    Hansen, P.
    INNVENTIA AB, Drottning Kristinas vag 61, Stockholm, Sweden .
    Development of nano-ligno-cellulose produced from mechanical pulp2014In: International Mechanical Pulping Conference, IMPC 2014, 2014Conference paper (Refereed)
    Abstract [en]

    The objective in this work was to develop a methodology for producing mechanical pulp based nano-ligno-cellulose (NLC) from fines fractions. Also there has been a great deal of enthusiasm to evaluate particle size distribution of NLC. In this work the crill characterisation technique was used. The crill values of TMP and CTMP based nano-ligno-celluloses were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. Another objective was to utilise NLC as strength additives in paper and board grades. Laboratory sheets of CTMP and bleached kraft pulp (BKP), with the addition of their respective NLC, were made in a Rapid Kothen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z- strength and other important mechanical properties for similar sheet densities.

  • 26.
    Osong, Sinke Henshaw
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Norgren, Sven
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Lundberg, Mathias
    PulpEye AB, Box 279, SE-891 26 Örnsköldsvik, Sweden.
    Hansen, Peter
    INNVENTIA AB, Drottning Kristinas väg 61, Stockholm, Sweden.
    Crill: A novel technique to characterize nano-ligno-cellulose2014In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 2, p. 190-194Article in journal (Refereed)
    Abstract [en]

    The CrillEye is a technique for qualitatively assessing loose slender and fibrillar particles created during pulping. It has also been demonstrated that the crill measurement technique can easily be used to measure the degree of fibrillation of mechanical pulp based nano-ligno-cellulose (NLC). The measurement technique is based on an optical response of a suspension at two wavelengths of light; UV and IR. The UV light contains information on both fibres and crill, while IR only contains information on fibres. The resolution on the CrillEye module is based on optical response of the pulp and on an analogue signal analysis making it concentration independent. Characterization of particle-size distribution of nano-ligno-cellulose is both important and challenging. The objective of the work presented in this paper was to study the crill values of TMP and CTMP based nano-ligno-celluloses as a function of homogenization time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated fairly well with the homogenization time.

1 - 26 of 26
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