• Journal of Forest and Environmental Science
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• 제33권2호
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• pp.154-159
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• 2017

Enzymatic treatment was conducted to hydrolyze pure cellulose nanofiber (PCNF), holocellulose nanofiber (HCNF), and lignocellulose nanofiber (LCNF) for 6, 24 and 72 hours and thus-obtained nanofibers (1, 3, 5, 10 wt%) were used to reinforce polyvinyl alcohol (PVA). Glucose production yield was increased by enzymatic hydrolysis. Tensile strength and elastic modulus of all PVA nanocomposite reinforced three nanofibers were improved by increasing enzymatic hydrolysis time of nanofibers and these values were higher in order of nanocomposite reinforced with PCNF>HCNF>LCNF. Furthermore, tensile properties of nanocomposite with PCNF were increased by nanofiber content. Thermal stability of PVA was improved by adding nanofibers and by increasing nanofiber content.

• 한국표면공학회지
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• 제57권1호
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• pp.31-37
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• 2024

The surge in demand for lithium is primarily fueled by the expanding electric vehicle market, the necessity for renewable energy storage, and governmental initiatives aimed at achieving carbon neutrality. This study proposes a straightforward method for lithium extraction utilizing cellulose nanofiber (CNF) via a vacuum filtration process. This approach yields a porous CNF film, showcasing its potential utility as a lithium extractor and indicator. Given its abundance and eco-friendly characteristics, cellulose nanofiber (CNF) emerges as a material offering both economic and environmental advantages over traditional lithium extraction techniques. Hence, this research not only contributes to lithium recovery but also presents a sustainable solution to meet the growing demand for lithium in energy storage technologies.

• Journal of the Korean Wood Science and Technology
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• 제43권6호
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• pp.730-739
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• 2015

본 연구는 셀룰로오스 나노섬유를 닥나무 인피섬유 시트의 제조시 첨가하여, 닥나무 인피섬유 시트의 특성에 미치는 영향을 조사하였다. 형태학적 및 화학적 성질이 다른 5종류의 셀룰로오스 나노섬유, 즉 리그노셀룰로오스 나노섬유 (lignocellulose nanofiber, LCNF), 홀로셀룰로오스 나노섬유(holocellulose nanofiber, HCNF), 알칼리처리 홀로셀룰로오스 나노섬유(alkali-treated HCNF, AT-HCNF), TEMPO-산화 나노섬유(TEMPO-oxidated nanofiber, TEMPO-NF), 셀룰로오스 나노크리스탈(cellulose nanocrystal, CNC)을 제조하였으며, 각 나노섬유의 종류 및 첨가량이 닥나무 인피섬유시트 제조시의 여수시간 및 시트의 투기도, 평활도, 인장강도 특성에 미치는 영향을 조사하였다. 여수시간은 모든 나노섬유에 있어서 첨가량이 증가함으로서 길어졌으며, 5%의 첨가량에서 HCNF가 가장 여수시간이 길었다. 또한, 셀룰로오스 나노섬유 첨가량이 증가할수록 시트의 평활도, 인장강도 특성이 향상되었으며, 특히 0.1%의 극히 적은양의 나노섬유 첨가로도 비인장강도 및 탄성계수가 크게 향상되는 것을 알 수 있었다. 이러한 특성 향상은 닥나무 인피섬유 간에 교차적으로 적층되어 있는 셀룰로오스 나노섬유의 충전 효과에 기인하는 것을 전자현미경 사진을 통해 확인할 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.69-72
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• 2007

Cellulose is a beneficial material that has low cost, lightweight, high compatibility and biodegradability. Recently electroactive paper (EAPap) on cellulose base was discovered as a smart material and actuator through ion migration and piezoelectric effect. Furthermore cellulose has a potentiality to apply the display material, because of its high reflectivity, flexibility and high transmittance. The various shapes and height patterns of the Cellulose acetate (CA) solution, such as circle and honeycomb patterns, were fabricated and observed by field emission scanning electron microscope (FESEM, S4300 Hitachi). The resulting pattern showed uniform size in the large area without defect. After stretching the CA film with saponification process in the sodium methoxide in methanol solution, Most of the compositions become one directional ordered nanofibers below 50nm.

• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.119-129
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• 2014

This work undertook to prepare nanofibers of cellulose nanofibrils (CNF)/polyvinyl alcohol (PVA) composite by electrospinning, and characterize the electrospun composite nanofibers. Different contents of CNFs isolated from hardwood bleached kraft pulp (HW-BKP) by 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-mediated oxidation were suspended in aqueous polyvinyl alcohol (PVA) solution, and then electrospun into CNF/PVA composite nanofibers. The morphology and dimension of CNFs were characterized by transmission electron microscopy (TEM), which revealed that CNFs were fibrillated form with the diameter of about $7.07{\pm}0.99$ nm. Morphology of the electrospun nanofiber observed by field-emission scanning electron microscopy (FE-SEM) showed that uniform CNF/PVA composite nanofibers were manufactured at 1~3% CNF contents while many beads were observed at 5% CNF level. Both the viscosity of CNF/PVA solution and diameter of the electrospun nanofiber decreased with an increase in CNF content. The diameter and its distribution of the electrospun nanofibers helped explain the differences observed in their morphology. These results show that the electrospinning method was successful in preparing uniform CNF/PVA nanofibers, indicating a great potential for manufacturing consistent and reliable cellulose-based nanofibrils for scaffolds in future applications.

• 한국응용과학기술학회지
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• 제25권3호
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• pp.341-346
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• 2008

Cellulose nanofibers from microfibril cellulose (MFC) was prepared by hydrobromic acid (HBr) treatment at different concentrations. Polyvinyl alcohol (PVA) composite films at various loading level of nanofibers were manufactured by a film casting method. The analysis of degree of polymerization (DP), crystallinity ($X_c$) and molecular weight ($M_w$) of cellulose after acid treatment was conducted. The mechanical and thermal properties of the cellulose nanofibers reinforced PVA films were characterized using tensile tests and thermogravimetric analysis (TGA). The DP and $M_w$ of MFC by HBr hydrolysis considerably decreased, but $X_c$ showed no significant change. After acid hydrolysis, the diameter of cellulose nanofibers was in the range of 100 to 200 nm. The thermal stability of the films was steadily improved with the increase of nanofiber loading. There was a significant increase in the tensile strength of PVA composite films with the increase in MFC loading. Finally, 5 wt.% nanofiber loading exhibited the highest tensile strength and thermal stability of PVA composite films.

• Macromolecular Research
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• 제13권1호
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• pp.62-67
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• 2005

This paper investigated the effect of biodegradation behavior on the oxidation of cellulose nanofiber mats. The cellulose mats were produced through electro spinning. The diameter of an electrospun fiber varied from 90 to 240 nm depending on the electrospinning parameters, such as the solution concentration, needle diameter, and rotation speed of a grounded collector. Oxidized cellulose (OC).mats containing different carboxyl contents were prepared using $NO_2$ as an oxidant. The total carboxyl content of the cellulose nanofiber mats obtained after oxidation for 20 h was $20.6\%$. The corresponding carboxyl content was important from a commercial point of view because OC containing $16-24\%$ carboxyl content are used widely in the medical field as a form of powder or knitted fabric. Degradation tests of the OC mats were performed at $37^{\circ}C$ in phosphate-buffered saline (pH 7.4). Microscopy techniques were introduced to study the morphological properties and the degradation behavior of the OC mats. Morphological changes of the mats were visualized using optical microscopy. Within 4 days of exposure to PBS, the weight loss of the OC mats was $>90\%$.

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1291-1298
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• 2015

Five different polymer nanofibers, namely, polyaniline nanofiber (PANI), magnetically separable polyaniline nanofiber (PAMP), magnetically separable DEAE cellulose fiber (DEAE), magnetically separable CM cellulose fiber (CM), and polystyrene nanofiber (PSNF), have been used for the immobilization of lactase (E.C. 3.2.1.23). Except for CM and PSNF, three polymers showed great properties. The catalytic activities (k_cat) of the free, PANI, PAMP, and magnetic DEAE-cellulose were determined to be 4.0, 2.05, 0.59, and 0.042 mM/min·mg protein, respectively. The lactase immobilized on DEAE, PANI, and PAMP showed improved stability and recyclability. PANI- and PAMP-lactase showed only a 0-3% decrease in activity after 3 months of vigorous shaking conditions (200 rpm) and at room temperature (25℃). PANI-, PAMP-, and DEAE-lactase showed a high percentage of conversion (100%, 47%, and 12%) after a 1 h lactose hydrolysis reaction. The residual activities of PANI-, PAMP-, and DEAE-lactase after 10 times of recycling were 98%, 96%, and 97%, respectively.

• International Journal of Ocean System Engineering
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• 제1권4호
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• pp.180-184
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• 2011

Nanocomposites based on cellulose nanofibers have been studied for a considerable time since its first introduction, however real applications seem to have hardly developed to these days. The high-strength of cellulose nanofibers suggests the potential to reinforce plastics to produce composites for semi-structural or even structural applications. This paper discusses some of the attempts to produce such high-strength nanocomposites and the main challenges that have to be overcome to bring them into commercial products.

• 펄프종이기술
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• 제47권2호
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• pp.42-52
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• 2015

In this study, cellulose nanofibrils (CNF) were modified through carboxymethylation or TEMPO-mediated oxidation and their effects on ionicity and characteristics of sheet, film, and foam were investigated. Carboxymethylation was carried out on pulp fibers as a pre-treatment before preparation of CNF. The gel-like and translucent CNF hydrogel was obtained by grinding of carboxymethylated cellulose fibers. Carboxymethylated CNF film and freeze dried sheet showed higher transparency than that of untreated CNF. The CNF sheet with high strength and the CNF foam without large ice crystals were obtained by using the carboxymethylated CNF. TEMPO-mediated oxidation was carried out as a post-treatment of CNF. The zeta potential and charge demand of TEMPO-oxidized CNF were increased with an increase in oxidation time and addition amount of NaClO. The density of sheet made of TEMPO oxidized CNF was increased with the amount of oxidizing agent. The TEMPO oxidized cellulose nanofiber (TOCN) which was obtained from supernatant after centrifugation could be converted to transparent film.