Nanofibrilation of alkali-pretreated cellulose fiber using grinding treatment

doi:10.21203/rs.3.rs-3737232/v1

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Nanofibrilation of alkali-pretreated cellulose fiber using grinding treatment

https://doi.org/10.21203/rs.3.rs-3737232/v1

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The aim of this study is to explore the effect of strong alkali-pretreatment on manufacturing cellulose nanofibril s(CNFs) with mechanical (grinder) treatment. The structural change (from cellulose I to cellulose II) and sharply reduction in the yield of hemicellulose component (xylose) of cellulose fibers (bleached kraft pulp) were observed after strong NaOH (20 wt.%) pretreatment. However, the differences depending on treatment time (1 h or 2 h) were not significant. The subsequent mechanical (grinder) treatment did not lead to any significant changes in the chemical composition, specifically the sugar contents, of the cellulose fiber. Morphological analyses showed that generated micro- and nano-fibers in the suspension were gradually decreased with increasing mechanical pass number. Also, the mean width of the nanofibers produced from alkali-pretreated pulp was relatively thicker than those from untreated pulp. UV-transmittance and turbidity results showed that alkali pretreatment and subsequent mechanical treatment led to an increase in the nanofibril content. Therefore, alkali pretreatment and subsequent mechanical grinding provide a promising method for the efficient and cost-effective production of CNFs.

Cellulose nanofibers

Alkali pretreatment

Grinder

Bleached kraft pulp

The use of fossil fuel-based plastics has been identified as a contributing factor to global warming, primarily owing to the generation of microplastics post-disposal, which contaminates water, air, and soil. In 2010, 275 million metric tons (MMt) of plastic waste were produced by 192 coastal countries, with 4.8–12.7 MMt entering the ocean (Jambeck et al. 2015). These plastics may cause irreversible harm to nature and humans owing to their incomplete decomposition. Microplastics are of particular concern as they can infiltrate the bloodstream and brain, leading to serious health issues (Yin et al. 2022). In response, natural polymers such as cellulose, chitin, and collagen are emerging as eco-friendly, renewable alternatives. Cellulose, the most abundant natural resource on Earth, is synthesized by plants, microorganisms, and algae, and approximately 1.5 trillion tons is produced annually (Benabid et al. 2016) (Kim et al. 2015). Its hydrophilic, biodegradable, and biocompatible nature, owing to d-glucose bonds and numerous hydroxyl groups, makes it useful in the food, cosmetics, and pharmaceuticals industries and as a viscosity regulator (Ramon et al. 2022). To leverage the benefits of cellulose, research has focused on transforming it into cellulose nanofibrils (CNFs), which exhibit a high aspect ratio, surface area, crystallinity, transparency, and mechanical strength (Barbash et al. 2016). The vast application potential of CNFs, derived from their nanoscale advantages, has been confirmed through extensive empirical studies.

Various methods to manufacture CNFs, a natural polymer considered a promising alternative to plastics, have been researched; however, challenges remain in CNF production, primarily due to lower productivity and higher costs compared to synthetic polymers (de Assis et al. 2018). CNFs can be manufactured using various mechanical treatments (e.g., high-pressure homogenization and grinding), but these methods are energy-intensive for generating nanoscale cellulose particles (Shih et al. 2020). Thus, a range of chemical-pretreatment strategies, including TEMPO oxidation and phosphorylation, have been explored. However, a more efficient chemical-pretreatment process than the existing one is required in terms of cost-effectiveness, which includes process simplification, solvent reuse, and easy scalability.

The three primary mechanical treatments for CNF production are ultrafine grinding, homogenization, and microfluidization (Abdul et al. 2014). This study selected ultrafine grinding as the optimal CNF manufacturing process after a comparison of the energy consumption for the different mechanical treatments for CNF production yielded the following results: homogenization consumed 3,940 kJ/kg (1,095 kWh/ton), ultrafine grinding 620 kJ/kg (170 kWh/ton), and microfluidization 200, 390, 620 kJ/kg (56, 110, 175 kWh/ton) under the pressure conditions of 69, 138, 207 MPa per pass, respectively (Spence et al. 2011). Ultrafine grinding not only requires less energy, but also produces 2–10 times more CNFs compared to homogenization and microfluidization (Petroudy et al. 2021). Additionally, this method is suitable for mass production without equipment failure, irrespective of the particle size of the input material. In contrast, microfluidizers risk equipment damage due to locally concentrated high pressure and potential clogging issues, unless the particle size is reduced. Additionally, agglomeration may occur owing to storage or any other reasons even if the input particle size is reduced, thereby hindering continuous production (Li et al. 2022). Accordingly, grinding emerges as an effective mechanical method owing to its high treatment concentration and productivity. Therefore, this study investigates efficient CNF production using an ultrafine grinder.

The basic strategy of nanocellulose production involves chemically removing hemicellulose, which binds the cellulose fibers within microscale cellulose fibers, and physically disrupting the inter- and intra-molecular hydrogen bonds of cellulose.

Among alkali treatment chemicals, sodium hydroxide is an effective chemical traditionally used in wood chemistry for reducing hemicellulose and inducing changes in the crystalline structure of cellulose, thereby significantly modifying the cellulose properties. Sodium-hydroxide treatment is also cost-effective and readily recoverable. Due to these favorable attributes, sodium-hydroxide treatment has garnered increasing attention since the early 2010s as an industrially viable chemical pretreatment for hemicellulose removal (Correa et al. 2010).

Although alkali treatment is not a new chemical-treatment method, research on its application in CNF production is limited. Existing studies on chemical pretreatments have focused on oxidation processes using expensive catalysts, such as TEMPO, and little research has been conducted on CNF production combined with grinding. The significant potential of CNF as a plastic substitute has been recognized in the field of new materials through numerous application studies, such as research on CNF three-dimensional (3D) printing composites, including medical resins (Vidakis et al. 2022), and research on reinforced composites of nanocellulose mixed with with PVA (Li et al. 2013); however, high production cost are the main barrier to the commercialization of CNF products. Therefore, continuous research is needed to reduce CNF-production costs for the commercialization of low-carbon products using CNF.

This study aims to analyze the characteristics of CNFs that are mass-produced through alkali pretreatment and grinder treatment. To achieve this, the following questions are addressed for the combined alkali and grinding treatments: (1) Does pulp-hemicellulose reduction and the change in the crystalline structure of cellulose occur due to physical forces such as shear stress during the grinder treatment? (2) What are the limitations of the characteristics (e.g., morphology and relative content of nanofibers) of CNFs produced under harsh alkali and grinder treatments? (3) What is the exact chemical-reaction mechanism of NaOH that causes changes in the characteristics of the produced CNFs? For research toward commercialization, domestically available deciduous bleached kraft pulp (BKP) was utilized. A large-scale production grinder capable of processing 350–3500 kg/hr based on dry weight was employed, and the experiments were conducted on a scale of 0.1t, including 1 wt.% pulp. The manufactured pulp and CNFs were analyzed to determine their physical properties using X-ray diffraction (XRD), morphological characteristics using scanning electron microscopy (SEM) and fiber analysis, chemical properties using sugar-content analysis and the Zeta-potential, and optical properties using ultraviolet-visible (UV-VIS) spectrophotometry and turbidity measurements.

Materials

Hardwood BKP (Hw-BKP) of oak-acacia mixed Hw was used as the raw material, and sodium hydroxide (NaOH, > 98%, Daejung, Republic of Korea) was used for the alkali pretreatment.

Alkali pretreatment and mechanical treatment of Hw kraft pulp

Alkali pretreatment

For the alkali pretreatment, Hw-BKP was shredded into pieces approximately 2 cm in diameter and then dried. The pretreatment was then carried out for 1 h or 2 h using 20 wt% NaOH, following a modified TAPPI method (T203 cm-99), and the pulp was washed using a 200-mesh standard sieve until it reached a neutral pH.

Mechanical treatment

The grinder treatment was conducted by preparing a 1 wt% suspension of the alkali-pretreated Hw-BKP by adding tap water. A grinder (colloid mill, MKZA15-40J, Masuko Sangyo Co. Ltd., Japan) was used under conditions of -200 µm. This process was repeated up to a maximum of 80 times, with samples collected for analysis every 20 cycles.

Analysis of the physicochemical properties of the CNFs

Evaluation of crystalline structure

XRD analysis was performed on sheets made from the alkali- and grinder-treated Hw-BKP using an analyzer (DMAX-2500, Rigaku, Japan). The XRD patterns were recorded at a scan speed of 2 °/min in the range of 10°–40°, utilizing Cu-Ka radiation set at 40 kV and 200 mA.

Morphological characteristics

For the FE-SEM analysis, the Hw-BKP nanofiber suspension was diluted to 0.002 wt% and dispersed for 30 s using an ultrasonic homogenizer (VCX130, Sonics & Materials, USA). Vacuum filtration was then performed using a membrane filter (0.2 µm, PTFE, Advantec, Japan), followed by serial organic solvent substitution in tert-butyl alcohol (three times). The samples were stored at -60 ℃ for 24 h and then freeze-dried for 3 days using a freeze dryer (LP-03, Ilshin Biobase, Republic of Korea). The samples were then coated with iridium to a thickness of 2 nm using a sputter-coater (Leica EM ACE 600, Leica, Germany) and observed under an ultra high-resolution scanning electron microscope (S-4800, Hitachi, Japan) at an acceleration voltage of 5 kV.

Nanofiber-size characteristics

The particle size of the Hw-BKP nanofibers was analyzed by measuring the fiber diameter of 300 microfibers selected using the image-analysis program Image J (National Institutes of Health, Bethesda, MD, USA) based on SEM photographs. For the microfibers remaining in the suspension, 50 were randomly selected, and their average thickness was measured.

For the fiber-length measurement, the suspension of alkali-pretreated and grinder-treated Hw-BKP was quantified to a solid content of 0.1g, and fiber-length analysis was performed using an L&W fiber tester plus (ABBAB/Lorentzen & Wettre, Kista, Sweden).

Surface-charge characteristics

A suspension of 0.1 wt% was prepared using the alkali- and grinder-treated Hw-BKP. The Zeta potentials of the quantified samples in the suspension were measured and evaluated using a Zetasizer (Nano ZSP, Malvern Instruments, UK).

Composition characteristics

The alkali- and grinder-treated Hw-BKP was dried in a high-temperature oven at 105 ± 1°C. Primary acid hydrolysis was then performed on a 0.2-g dried sample for 2 h with 3 mL of 72% (w/w) sulfuric acid. The primary hydrolyzed solution was diluted with deionized water to a 4% concentration of sulfuric acid and then subjected to secondary acid hydrolysis at 121°C for 1 h using an autoclave. The hydrolyzed samples were filtered through a 0.45-µm membrane syringe filter (Whatman, GE Healthcare, UK) and analyzed using high-pressure liquid chromatography (1290 Infinity II, Agilent Technologies, USA). An Aminex HPX-87H column (300 × 7.8 mm, Bio-Rad Laboratories, Inc., Hercules, CA, USA) and refractive-index detector (1290 Infinity LC, Agilent Technologies, Santa Clara, USA) were used. During the analysis, the column temperature was maintained at 40°C, and the mobile phase was set and measured at 0.6 mL/min, using 0.01 N sulfuric acid, to evaluate the changes in the cellulose components resulting from the alkali and grinder treatments.

Optical properties

A 0.04 wt% suspension of alkali- and grinder-treated Hw-BKP was prepared and homogenized using a sonicator (VCX 130, Vibra Cell, USA) at 300 W for 3 min. The suspension was then centrifuged (Supra R22, Hanil, Republic of Korea) at 1,000g for 15 min to separate the supernatant. The properties of the nanofibers due to the alkali pretreatment and grinder treatment were evaluated in the wavelength range of 200–800 nm using a UV/VIS spectrophotometer (Optizen POP, Mecasys Co., Ltd, Republic of Korea), and the turbidity of the supernatant was measured using a turbidity meter (TL2360, Hach Company, USA).

Changes in the properties of Hw-BKP with alkali-treatment time

Figure 1 illustrates the changes in the properties of Hw pulp particles with the alkali treatment time at 20 wt.%. Figure 1a displays the changes in pulp sugar yield after the alkali treatment. Glucose derived from cellulose and xylose derived from hemicellulose exhibited an increase of up to 80% and a decrease to below 3%, respectively, whereas arabinose displayed no noticeable change owing to its trace amount. Hemicellulose can be readily removed even under mild alkaline conditions (3–10 wt%). In this study, the use of a strong alkali (20 wt%) led to the breakdown and removal of hemicellulose, resulting in a relative increase in cellulose content (Li et al. 2015; Carrillo et al. 2022). The sugar components of the pulp were observed depending on the alkali-treatment time; little change was observed in xylose, whereas a marginal decrease was noted in glucose. This suggests that prolonged treatment under strong alkaline conditions impacts the amorphous regions of cellulose. Figure 1b presents the XRD results based on the alkali treatment time. Untreated Hw-BKP exhibited crystalline peaks at approximately 16° (110) and 22° (200), indicative of the cellulose I structure in native cellulose chains (Lekha et al. 2016). After the alkali treatment, characteristic peaks were observed at approximately 12° (1–10), 20° (110), and 22.3°–22.6° (020). This is indicative of a transition from the cellulose I to cellulose II structure in the cellulose crystalline structure, a change attributed to swelling and washing during the alkali treatment. The alkali-treatment time did not significantly affect the cellulose structure. Figure 1c presents the Z-potential results based on the alkali-treatment time. The surface-potential difference is an important indicator of the colloidal state of the suspension. A decrease in the absolute value of the pulp-fiber surface potential was observed after the alkali treatment, but no significant treatment time-dependent change was detected. The change in surface potential is considered to be due to the reduction of hemicellulose, which contains many hydroxyl groups, following the alkali treatment, which is supported by the sugar-analysis results (Fig. 1a). Figure 1d displays SEM images based on the alkali-treatment time, and Figs. 1e and 1f illustrate the physical properties of the alkali-treated pulp fiber particles (average particle size, coarseness, microfiber content). SEM analysis revealed that the originally stiff fibers became more flexible and twisted after the alkali treatment, and a decrease in fiber thickness and length was noted (Fig. 1e). No noticeable change in the microfiber content was observed. Interestingly, the characteristic value of coarseness, proportionate to cell-wall thickness, increased after the alkali treatment (Fig. 1f). This increase is likely attributable to the strong alkali treatment of 20 wt% used in this study, which led to the removal of most hemicellulose through mercerization and the swelling of the cellulose I molecular structure due to NaOH. This was followed by recombination into an antiparallel structure (Scheme 1) after alkali washing, resulting in the change in crystalline structure explained in the XRD result (Wang et al. 2014; Wang et al. 2018). As depicted in Scheme 1, cellulose I is composed of a monoclinic crystalline unit affected by three different forces (hydrogen, covalent, and van der Waals forces) depending on the dimensional direction (Altaner et al. 2014). First, hydrogen bonding occurs between adjacent hydrogens of the hydroxyl groups, imparting crystallinity to the cellulose. The hydroxyl groups, located in the equatorial direction, extend in the a direction of Scheme 1, with a bond strength of approximately 8 kcal/mol^-1. Second, covalent bonds are formed in the b direction, with the strongest bond strength of 550 kcal/mol^-1 among the three bonds. Lastly, van der Waals bonds in the axial direction (c direction) have the weakest bond strength (5 kcal/mol^-1). Notably, after the alkali treatment, the lengths of the hydrogen and covalent bonds in the unit cell remained almost unchanged; however, the length of the van der Waals bonds in the axial direction increased, as indicated in Scheme 1. This may account for the increase in cell-wall thickness observed in the coarseness results in Fig. 1f, which is likely owing to the increase in the axial length of the unit cell driven by bond strength (Holtzapple 1993).

CNF-production characteristics related to alkali pretreatment and grinder treatment

The results of the XRD, sugar, and Zeta-potential analyses of the cellulose suspension particles, treated with the grinder both before and after alkali treatment and over time, are shown in Figs. 2a–c, 2 d–f, and 3 g–i, respectively. As previously mentioned, the sugar-content analysis and XRD results primarily show the effects of the alkali treatment alone, with no significant changes observed based on the number of mechanical treatments. In this context, pulp is composed of microscale particles comprising cellulose-fiber bundles. The pulp used in this study was bleached kraft pulp, primarily consisting of cellulose and hemicellulose, with the lignin removed. It is characterized by its structure, in which rigid crystalline cellulose chains are partially cemented by amorphous hemicellulose. Initially, we anticipated that the strong shear stress from the grinder discs would significantly decrease the sugar content (xylose and arabinose) of hemicellulose as the pulp particles broke down. However, the expected decrease in sugar content was not observed. As indicated in Figs. 1 and 2a–c, the changes in the sugar components of the particles were more influenced by the chemical treatment than by the mechanical treatment. The same trend was observed in the crystalline structure. Untreated pulp exhibited an increasing trend in the absolute value of the Zeta potential as the grinder-treatment counts increased. This may be attributed to the particles breaking down under the grinder treatment, which increased the surface area and exposed more of the remaining hemicellulose on the surface. Unlike in the untreated samples, the absolute value of the Zeta potential was approximately 15 mV, showing a marginal decrease or remaining constant regardless of the grinder-treatment counts. When the absolute value of the surface potential difference is above 30 mV, the particles are considered to be stably dispersed in the solvent (Mtibe et al. 2015). The CNF manufacturing conditions used in this study for cellulose nanofibrillation with the grinder were extremely harsh at -200 µm, a condition rarely seen in previous studies. Despite these conditions, the Zeta-potential results suggest that additional dispersing agents may be required for applications in areas requiring dispersion stability when using CNF suspensions produced solely by grinder treatment.

Figure 3a and 3b illustrate the microfiber content and coarseness of the CNF suspensions prepared using varying numbers of mechanical treatments in a grinder. The microfiber proportion increased with a longer alkali-treatment time and a higher number of mechanical treatments. For the unpretreated pulp, the microfiber content gradually increased with an increase in the number of mechanical treatments. In contrast, for the alkali-pretreated pulp, a marked increase in microfiber content was observed after 60 treatments. In terms of alkali treatment time, the suspensions made from pulp treated for 2 h showed higher microfiber content than those made from pulp treated for 1 h. The coarseness results showed the opposite trend. In untreated pulp, coarseness decreased marginally with more mechanical treatments, whereas in alkali-pretreated pulp, a sharp decrease in coarseness was noted from 60 treatments onwards. In addition, the coarseness tended to decrease more when exposed to a longer alkali-treatment time (Xu et al. 2014). According to ISO 16065-2 (Pamidi et al. 2020), microfibers are defined as fibers shorter than 200 µm. Importantly, microfiber content as determined by a fiber-quality analyzer does not necessarily equate to nanofiber content. Therefore, these results should be interpreted alongside SEM images for an accurate size analysis.

Figures 4 and 5 show the low-magnification (x200) and high-magnification (x30k) images of the suspension samples prepared in this study, respectively. As shown in the low-magnification photographs in Fig. 4, the number and size of microscale cellulose particles decreased with increasing alkali-treatment time and grinder-treatment counts. However, in the untreated pulp, a larger number of microscale fibers were observed compared to the alkali-treated sample. In the high-magnification photographs in Fig. 5, microscale particles exhibit a nanofibrillated morphology. In the untreated pulp, nanofibrillated particles were attached like cobwebs on the surface of microfibers, and their widths were smaller and more uniform than those in the alkali-treated sample (compared at 80 grinder-treatment counts). In the alkali-treated pulp, as the grinder-treatment counts increased, microscale particles increasingly lost their original morphology and crush. They formed a net-like microfibril structure, showing nanofibrillated particles that were somewhat thicker compared to those in untreated pulp. This result is opposite to our initial hypothesis that using alkali-treated pulp with reduced hemicellulose content would yield finer nanoparticles. As explained in Scheme 1, the Cell-1 crystalline structure had a parallel structure, where non-reducing and reducing ends of molecules were arranged in the same direction, and the unit chains had weak van der Waals forces in the axial direction. In contrast, the alkali treatment altered the parallel structure of Cell-1 into a non-parallel Cell-2 structure. A notable feature in the Cell-2 structure is that as the crystalline structure rearranges, hydrogen bonds form in the axial direction, and the interaction forces between unit chains become stronger than those in the Cell-1 structure (Halonen et al. 2013). Therefore, as shown in Scheme 2, when shear stress is applied between the grinder discs, the thin untreated cellulose with weak chain-interaction forces is likely to exhibit fibers separately falling off from the surface. However, in the case of thicker alkali-treated cellulose with stronger chain-interaction forces, chunks are expected to fall off under strong shear stress, as shown in Fig. 5.

Figure 6 shows the length-evaluations of the microfibers present in the suspension using a fiber-quality analyzer. The microfiber lengths tended to decrease with increasing treatment counts and alkali-treatment time. The sizes of the micro- and nanoscale particles present in the grinder-treated suspensions of untreated and alkali-treated pulp were evaluated using SEM, the results of which are presented in Fig. 7. As anticipated, in the SEM image, the thickness of the microfibers tended to decrease in the alkali-treated pulp compared to the untreated pulp, regardless of the grinder-treatment counts, whereas the nanofiber thickness tended to increase. This trend was also observed with increasing alkali-treatment time. As described in Scheme 2, in cellulose fibers with the cellulose I structure, the molecular chains were horizontally oriented and firmly bonded owing to strong van der Waals forces. Only the surface of the fiber bundle was scraped by the disc, even under strong shear stress, thereby forming nanofibers. However, in cellulose molecules with the cellulose II structure, the microfibers became thinner while the generated nanofibers became thicker. This may have been owing to the weakened non-covalent bonding and structural integrity under the deformation of the original structure, resulting in the splitting of the interior of a chain bundle (Rahman et al. 2007; Holtzapple 1993).

Optical properties of alkali- and grinder-treated Hw-BKP

We evaluated the nanomaterial content in the suspensions prepared in this study by obtaining CNF suspensions using the centrifugation method described in previous studies (Naderi et al. 2014; Desmaisons et al. 2017). We evaluated the light transmittance and turbidity of the centrifuged suspensions to indirectly assess the CNF content, as shown in Figs. 8 and 9, respectively. The UV-spectrophotometer analysis of the nanofibers separated by centrifugation revealed that transmittance in the 200–800 nm range decreased for all treatments in increasing order of nanofiber content. This suggests that the UV transmittance decreases as the nanofiber content increases. Particularly, the transmittance of ultraviolet A (UVA, 320–400 nm) and ultraviolet B (UVB, 280–320 nm) decreased, which may be owing to the scattering and absorption of UV by nanoparticles (Rabani et al. 2022). The alkali-pretreated pulp contained more nanofibers than the untreated pulp, and the turbidity also increased to 22.37 and 31.60 NTU following 1 h and 2 h of alkali pretreatments, respectively, and 80 counts of grinder treatment. This indicates that the nanofiber content resulting from mechanical treatment increased after the alkali pretreatment. Therefore, although alkali pretreatment marginally increases the width of nanofibers, it also enhances the nanofiber content, which positively impacts nanofibrillation efficiency (Nechyporchuk et al. 2016).

This study investigates the significant positive effects of alkali pretreatment and mechanical (grinder) treatment on the production of CNFs. In our analysis, Hw-BKP subjected to 20 wt% NaOH pretreatment for 1 and 2 h underwent a transformation from cellulose I to cellulose II in its crystalline structure. This strong alkali treatment led to the separation and reduction of hemicellulose, consequently altering the cellulose-hemicellulose composition within the pulp fiber. The alkali treatment caused the pulp to swell, leading to the detachment of its weaker ends and a reduction in fiber length. Contrastingly, mechanical treatment (using a grinder) did not induce any change in the crystalline structure, indicating that mechanical treatment did not alter the composition of the cellulose and hemicellulose. However, CNFs were observed to be thicker after alkali pretreatment compared to untreated samples, which may be attributable to the changed orientation of the cellulose molecules. Alkali pretreatment followed by mechanical treatment resulted in a higher yield of microfibers in the pulp compared to untreated pulp, a finding corroborated by UV and turbidity analyses of the separated CNFs. Notably, an increase in nanofiber production was observed after approximately 60–80 iterations of grinder treatment. Thus, alkali pretreatment is a cost-effective and efficient chemical method to augment nanofibrillation productivity.

Acknowledgements/Funding

This study was supported by the National Institute of Forest Science (grant number: FP0701-2021-02) and the Korea Forest Service (grant number: 2021354A00-2023-AC03-1).

Availability of data and material

Not applicable.

Conflicts of interests

The authors declare no conflicts of interest.

Author Contributions

Kyojung Hwang: Conceptualization, Methodology, Writing-Original Draft. Jisoo Park: Methodology, Formal analysis. Danbee Lee: Methodology, Investigation. Jaegyoung Gwon: Conceptualization, Methodology, Writing-Review&Editing, Supervision.Sang-Jin Chun: Investigation, Validation. Tai-Ju Lee: Writing-Review&Editing. Jin-Ho Seo: Investigation

Abdul KHPS, Davoudpour Y, Nazrul IM, Mustapha A, Sudesh K, Dungani R, Jawaid M (2014) Production and modification of nanofibrillated cellulose using various mechanical processes: A review. Carbohydr Polym 99:649-665. https://doi.org/10.1016/j.carbpol.2013.08.069
Altaner CM, Thomas LH, Fernandes AN, Jarvis MC (2014) How cellulose stretches: Synergism between covalent and hydrogen bonding. Biomacromolecules 15: 791-798. https://doi.org/10.1021/bm401616n
Barbash VA, Yaschenko OV, Alushkin SV, Kondratyuk AS, Posudievsky OY, Koshechko VG (2016) The effect of mechanochemical treatment of the cellulose on characteristics of nanocellulose films. Nanoscale Res Lett 11:410-417. https://doi.org/10.1186/s11671-016-1632-1
Benabid FZ, Zouai F (2016) Natural polymers: Cellulose, chitin, chitosan, gelatin, starch, carrageenan, xylan and dextran. Alger J Nat Prod 4:348-357. https://doi.org/10.5281/zenodo.199036
Carrillo-Varela I, Vidal C, Vidaurre S, Parra C, Machuca A, Briones R, Mendonca RT (2022) Alkalization of kraft pulps from pine and eucalyptus and its effect on enzymatic saccharification and viscosity control of cellulose. Polymers 14:3127-3148. https://doi.org/10.3390/polym14153127
Correa AC, de Morais Teixeira E, Pessan LA, Mattoso LHC (2010) Cellulose nanofibers from curaua fibers. Cellulose 17:1183-1192. https://doi.org/10.1007/s10570-010-9453-3
de Assis CA, Iglesias MC, Bilodeau M, Johnson D, Phillips R, Peresin MS, Bilek EM, Rojas OJ, Venditti R, Gonzalez R (2018) Cellulose micro- and nanofibrils (CMNF) manufacturing-financial and risk assessment. Biofuel Bioprod Biorefin 12:251-264. https://doi.org/10.1002/bbb.1835
Desmaisons J, Boutonnet E, Rueff M, Dufresne A, Bras J (2017) A new quality index for benchmarking of different cellulose nanofibrils. Carbohydr Polym 174:318-329. https://doi.org/10.1016/j.carbpol.2017.06.032
Halonen H, Larsson PT, Iversen I (2013) Mercerized cellulose biocomposites: A study of influence of mercerization on cellulose supramolecular structure, water retention value and tensile properties. Cellulose 20:57-65. https://doi.org/10.1007/s10570-012-9801-6
Holtzapple MT (1993) Cellulose. In: Macrae R, Robinson RK, Sadler MJ (eds) Encyclopedia of food science, Food technology and nutrition, Academic press, London, pp 2731-2738.
Jambeck JR, Geyer R, Wilcox C, Siegler T, Perryman M, Andrady A, Ramani N, Law KL (2015) Plastic waste inputs from land into the ocean. Science 347:768-771. 10.1126/science.1260352
Kim JH, Shim BS, Kim HS, Lee YJ, Min SK, Jang D, Abas Z, Kim J (2015) Review of nanocellulose for sustainable future materials. Int J Precis Eng Manuf - Green Technol 2:197-213. https://doi.org/10.1007/s40684-015-0024-9
Lekha P, Mtibe A, Motaung TE, Andrew JE, Sithole BB, Gibril M (2016) Effect of mechanical treatment on properties of cellulose nanofibrils produced from bleached hardwood and softwood pulps. Maderas: Cienc Tecnol 18:457-466. http://dx.doi.org/10.4067/S0718-221X2016005000041
Li J, Liu Y, Duan C, Zhang H, Ni Y (2015) Mechanical pretreatment improving hemicelluloses removal from cellulosic fibers during cold caustic extraction. Bioresour Technol 192:501-506. https://doi.org/10.1016/j.biortech.2015.06.011
Li J, Zhang F, Zhong Y, Zhao Y, Gao P, Tian F, Zhang X, Zhou R, Cullen PJ (2022) Emerging food packaging applications of cellulose nanocomposites: A review. Polymers 14:4025-4056. https://doi.org/10.3390/polym14194025
Liu D, Sun X, Tian H, Maiti S, Ma Z (2013) Effects of cellulose nanofibrils on the structure and properties on PVA nanocomposites. Cellulose 20:2981-2989. https://doi.org/10.1007/s10570-013-0073-6
Mtibe A, Linganiso LZ, Mathew AP, Oksman K, John MJ, Anandjiwala RD (2015) A comparative study on properties of micro and nanopapers produced from cellulose and cellulose nanofibers. Carbohydr Polym 118:1-8. https://doi.org/10.1016/j.carbpol.2014.10.007
Naderi A, Lindstrom T, Pettersson T (2014) The state of carboxymethylated nanofibrils after homogenization-aided dilution from concentrated suspensions: A rheological perspective. Cellulose 21:2357-2368. https://doi.org/10.1007/s10570-014-0329-9
Nechyporchuk O, Belgacem MN, Bras J (2016) Production of cellulose nanofibrils: A review of recent advances. Ind Crops Prod 93:2-25. https://doi.org/10.1016/j.indcrop.2016.02.016
Pamidi TRK, Johansson O, Lofqvist T, Shankar V (2020) Comparison of two different ultrasound reactors for the treatment of cellulose fibers. Ultrason. Sonochem 62:104841-104848 https://doi.org/10.1016/j.ultsonch.2019.104841
Petroudy SRD, Chabot B, Loranger E, Naebe M, Shojaeiarani J, Gharehkhani S, Ahvazi B, Hu J, Thomas S (2021) Recent advances in cellulose nanofibers preparation through energy-efficient approaches: A review. Energies 14: 6792-6822. https://doi.org/10.3390/en14206792
Rabani I, Jang H, Park YJ, Tahir MS, Lee YB, Moon EY, Song JW, Seo YS (2022) Titanium dioxide incorporated in cellulose nanofibers with enhanced UV blocking performance by eliminating ROS generation. RSC Adv 12:33653-33665. https://doi.org/10.1039/D2RA06444H
Rahman MM, Khan MA (2007) Surface treatment of coir (Cocos nucifera) fibers and its influence on the fibers' physico-mechanical properties. Compos Sci Technol 67: 2369-2376. https://doi.org/10.1016/j.compscitech.2007.01.009
Morcillo-Martín R, Espinosa E, Rabasco-Vílchez L, Sanchez LM, de Haro J, Rodríguez A (2022) Cellulose nanofiber-based aerogels from wheat straw: Influence of surface load and lignin content on their properties and dye removal capacity. Biomolecules 12:232-248. https://doi.org/10.3390/biom12020232
Shih YF, Kotharangannagari VK, Tsou TC (2020) Development of eco-friendly modified cellulose nanofiber reinforced polystyrene nanocomposites: thermal, mechanical, and optical properties. J Polym Res 27:181-190. https://doi.org/10.1007/s10965-020-02156-8
Spence KL, Venditti RA, Rojas OJ, Habibi Y, Pawlak JJ (2011) A comparative study of energy consumption and physical properties of microfibrillated cellulose produced by different processing methods. Cellulose 18:1097-1111. https://doi.org/10.1007/s10570-011-9533-z
Vidakis N, Petousis M, Michailidis N, Kechagias JD, Mountakis N, Argyros A, Boura O, Grammatikos S (2022) High-performance medical-grade resin radically reinforced with cellulose nanofibers for 3D printing. J Mech Behav Biomed Mater 134:105408-105420. https://doi.org/10.1016/j.jmbbm.2022.105408
Wang H, Chen C, Fang L, Li S, Chen N, Pang J, Li D (2018) Effect of delignification technique on the ease of fibrillation of cellulose II nanofibers from wood. Cellulose 25:7003-7015. https://doi.org/10.1007/s10570-018-2054-2
Wang H, Li D, Yano H, Abe K (2014) Preparation of tough cellulose II nanofibers with high thermal stability from wood. Cellulose 21:1505-1515. https://doi.org/10.1007/s10570-014-0222-6
Xu H, Li B, Mu X, Yu G, Liu C, Zhang Y, Wang H (2014) Quantitative characterization of the impact of pulp refining on enzymatic saccharification of the alkaline pretreated corn stover. Bioresour Technol 169:19-26. https://doi.org/10.1016/j.biortech.2014.06.068
Yin K, Lu H, Zhang Y, Hou L, Meng X, Li J, Zhao H, Xing M (2022) Secondary brain injury after polystyrene microplastic-induced intracerebral hemorrhage is associated with inflammation and pyroptosis. Chem Biol Interact 367:110180. https://doi.org/10.1016/j.cbi.2022.110180

No competing interests reported.

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Scheme 1 The cellulose I (parallel) and II (antiparallel) structures
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Scheme 2 Disintegration mechanism of alkali-treated and untreated cellulose fiber

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Editorial decision: Revision requested
21 Jan, 2024
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12 Dec, 2023
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First submitted to journal
11 Dec, 2023

You are reading this latest preprint version

Nanofibrilation of alkali-pretreated cellulose fiber using grinding treatment

Status:

Version 1

Abstract

Figures

Introduction

Materials and Methods

Materials

Alkali pretreatment and mechanical treatment of Hw kraft pulp

Alkali pretreatment

Mechanical treatment

Analysis of the physicochemical properties of the CNFs

Evaluation of crystalline structure

Morphological characteristics

Nanofiber-size characteristics

Surface-charge characteristics

Composition characteristics

Optical properties

Results and discussion

Changes in the properties of Hw-BKP with alkali-treatment time

CNF-production characteristics related to alkali pretreatment and grinder treatment

Optical properties of alkali- and grinder-treated Hw-BKP

Conclusions

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1