Improving the mechanical properties of CNF films by NMMO partial dissolution with hot calender activation

Orelma, Hannes; Korpela, Antti; Kunnari, Vesa; Harlin, Ali; Suurnäkki, Anna

doi:10.1007/s10570-017-1229-6

Cited by 19 publications

(12 citation statements)

References 37 publications

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“…The welding procedure is applied to aim the mechanical properties enhance and promote nanocellulose surface patterning. Even though some previous works report the welding surface treatment for natural and cellulose-based fibers and films 18, [22][23][24]26 and more recently the use of ILs for improving transparency and mechanical performance in microfibers and papers based materials 34,28 , the present work presents the treatment of nanofibrillated surfaces using distillable ILs; these ILs in contrast to the traditional ILs can be recyclable by distillation with recoveries and purities over 99% 29,36 . Distillable ionic liquids are ILs that can be recovered by distillation.…”

Section: Introductionmentioning

confidence: 99%

Solvent Welding and Imprinting Cellulose Nanofiber Films Using Ionic Liquids

et al. 2018

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Cellulose nanofiber films (CNFF), were treated via a welding process using ionic liquids (ILs). Acid-base conjugated ILs derived from 1,5-diazabicyclo[4.3.0]non-5-ene [DBN] and 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) were utilized. The removal efficiency of ILs from welded CNFF was assessed using liquid-state nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared spectroscopy (FTIR). The mechanical and physical properties of CNFF indicated surface plasticization of CNFF, which improved transparency. Upon 2 treatment, the average CNFF toughness increased by 27 % and the films reached a Young modulus of ~5.8GPa. These first attempts for IL 'welding' show promise to tune bio-based films surfaces, expanding the scope of properties for the production of new bio-based materials in a green chemistry context. The results of this work are highly relevant to the fabrication of CNFFs using ionic liquids and related solvents. nanocomposites, transparent films, layer-by-layer films, paper products, cosmetics, barrier/separation membranes, transparent-flexible electronics, batteries, supercapacitors, catalytic supports, continuous fibers and textiles, food coatings, healthcare, antimicrobial films, biomedical and tissue engineering scaffolds, pH-responsive CNMs, drug delivery, among others 2. The sustainable preparation of cellulose-based nanomaterials is techno-economically challenging since this requires a low energy consumption process without the use, or production of, hazardous chemicals. The benefits are the production of high mechanical performance fibers and films, which 3 have potential applications as textiles, support for particles, and as composite materials for catalytic and electrochemical applications 3. Nanocellulose can form self-standing, thermallystable films and "nano-papers", thus this material has been strongly advocated as potential replacement for traditional packaging materials, primarily based on glass, aluminum, and fossilderived synthetic plastics 4-16 , but in many cases, such applications require an improvement of their physical and mechanical properties, in order to enhance their use 13,17. At this respect, the novel concept of welding has been introduced by Haverlhals 18-21. In this process, the surface of adjacent natural fibers (cotton, silk, and hemp) is plasticized and merged to create a congealed network using ILs such as 1-ethyl-3-methylimidazolium acetate ([emim][OAc]), a well-known cellulose-dissolving ionic liquid (IL). The welding process is intended mainly for cellulosic and protein-based fibers with the purpose to improve mechanical properties, synthesis of composites and functionalization of materials 18,22. The welding procedure has been used for modifying mainly cellulose macrofibers (not hydrolyzed neither treated fibers) to produce electrodes, catalysts, materials with special magnetic and electric features 23,24 , and synthesis of composites with improved mechanical properties 25. The same concept, using N-methylmorpholine-N-oxide (NMMO), was use...

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Section: Introductionmentioning

confidence: 99%

Solvent Welding and Imprinting Cellulose Nanofiber Films Using Ionic Liquids

et al. 2018

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“…As a means to improve wet‐strength it was shown that photo‐crosslinking can be utilized to produce filaments using wet spinning, [ 29 ] where benzophenone‐activated wood‐pulp TCNF was used as the spinning dispersion. [ 30 ] The dry filaments were UV‐treated and characterized with respect to mechanical properties in dry and wet states. The crosslinked filaments showed significantly lower apparent density (0.70 g cm −3 ) compared to pure TCNF‐filaments (1.22 g cm −3 ) that were used as reference.…”

Section: Improvements and Tuning Of Filament Propertiesmentioning

confidence: 99%

Elucidating the Opportunities and Challenges for Nanocellulose Spinning

2020

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In comparison to natural fibers, such as silk-, cotton-, or wool-fibers, man-made fibers refer to fibers fabricated from either synthetic or natural polymers. Man-made fibers from synthetic polymers (the largest volume of man-made fibers) are mainly produced from fossil-based resources, such as oil or gas. Examples of commonly used polymers are polyamides, polyesters, polyethylene, or polyurethanes. As a result of a century of developments within the area of polymer science and processing, it is currently possible to control the hierarchical structure of synthetic fibers, from the atomistic level up to the fiber level. Thus, one can address the properties and functionalities of the final fibers by developments on all hierarchical levels. Similar to synthetic fibers, natural fibers are synthesized from the atomic level up to the fiber level. The processes are designed by evolution, generally in the presence of water, to provide sufficient mechanical strength and toughness. Natural fibers are also biodegradable. When fabricating man-made fibers from natural polymers, the starting point is to use polymers extracted from biological sources, such as cellulose from wood pulp. Hence it is only possible to control the structure can thus only be controlled from the polymer scale and up. Cellulose represents the starting polymer for the first fabricated man-made fibers, i.e., Rayon, [1] also called regenerated cellulose fibers. In the preparation of regenerated cellulose fibers, highly purified cellulose is subjected to a dissolving process to extract individualized cellulose polymer chains. The biosynthesis in the plant cell wall forms nanofibrils from parallel polymer chains crystallized in a lattice referred to as Cellulose I, [2] and the dissolving process breaks the intermolecular bonds to individualize the chains to form a polymer solution. The cellulose polymer solution is spun using a spinneret and precipitated into continuous filaments to form the final regenerated cellulose fiber. The result of the precipitation process and drying is a different crystalline lattice called Cellulose II, which is more thermodynamically stable than Cellulose I. Regarding the mechanical performance as a building block, Cellulose I is significantly stiffer compared to Cellulose II. [3] The production of regenerated cellulose fibers depends on biological processes for producing the cellulose polymer since there are no industrial processes capable of producing synthetic cellulose polymer chains. Man-made continuous fibers play an essential role in society today. With the increase in global sustainability challenges, there is a broad spectrum of societal needs where the development of advanced biobased fibers could provide means to address the challenges. Biobased regenerated fibers, produced from dissolved cellulose are widely used today for clothes, upholstery, and linens. With new developments in the area of advanced biobased fibers, it would be possible to compete with high-performance synthetic fibers such as glass fibers and carbon...

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“…Significant differences were observed in the C4 peak between the CP/MAS and Bloch decay mode. The strong C4 peak of crystalline cellulose between 86 and 92 ppm disappeared in the Bloch decay mode, , and the strong −CH 2 –N peak of crystalline cellulose (48 and 43 ppm) appeared, the strong −CO–NH– peak of crystalline cellulose (170 ppm) appeared, and the aromatic ring peak for IP-NF-BCM (136 and 127 ppm) appeared.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Cellulose-Based Nanofiltration Membranes by Interfacial Polymerization with Piperazine and Trimesoyl Chloride

Shi

Liu

Huang

et al. 2018

ACS Sustainable Chem. Eng.

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A hydrophilic bamboo cellulose nanofiltration membrane (IP-NF-BCM) was prepared through interfacial polymerization (IP) of amino-functional piperazine (PIP) and 1,3,5-trimesoyl chloride (TMC) on a cellulose surface. The in situ formation of polyamide into the mesoporous structure of the regenerated cellulose film created a uniform microporous membrane, which can be used for water softening by nanofiltration. The interfacial polymerization reaction conditions were optimized in terms of the performance of resultant nanofiltration membranes. The chemical structure, morphology, and surface charge of the composite membranes were characterized based on thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), nuclear magnetic resonance (NMR), and Brunauer–Emmett–Teller (BET) nitrogen absorption. The water permeation and salt rejection capability of the bamboo cellulose thin-film-composite nanofiltration membranes were evaluated using 500 ppm salt solutions at 0.5 MPa pressure. Results show that the rejection rate for NaCl reached 40% and water flux reached 15.64 L/(m2·h). The average pore size of the bamboo cellulose thin-film-composite membranes was 1.0 nm.

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Improving the mechanical properties of CNF films by NMMO partial dissolution with hot calender activation

Cited by 19 publications

References 37 publications

Solvent Welding and Imprinting Cellulose Nanofiber Films Using Ionic Liquids

Solvent Welding and Imprinting Cellulose Nanofiber Films Using Ionic Liquids

Elucidating the Opportunities and Challenges for Nanocellulose Spinning

Preparation and Characterization of Cellulose-Based Nanofiltration Membranes by Interfacial Polymerization with Piperazine and Trimesoyl Chloride

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