• Microbiology and Biotechnology Letters
• /
• v.45 no.1
• /
• pp.1-11
• /
• 2017

In this review, we focus on one of the most attractive biomaterials, microfibrillated cellulose (MFC). MFC, a type of nanocellulose, mainly originates from cellulose in lignocellulosic biomass. MFC represents one of incredible important natural resources due to its abundancy, renewability, and sustainability. MFC is produced through mechanical pretreatment, and it is composed of various sizes of microfibers, ranging from a few nanometers to a few micrometers. Because of the heterogenetic compositions of MFC, it possesses superior properties as a material, such as high surface area, high aspect ratio, and peculiar insolubility as a biomaterial. These properties allow MFC to be used in various bio-industries, from the traditional pulp industry to the high-tech food/bio/chemical/medical industries. However, it is difficult to use MFC on a commercial scale owing to the high energy input required during its production and the challenge of controlling its reactivity. Therefore, future studies should be focused on accurately characterizing MFC's surface morphologies, regulating its characteristics in a desirable direction, and standardizing proper guidelines for the analysis of surface morphologies its analysis.

• Composites Research
• /
• v.35 no.3
• /
• pp.153-160
• /
• 2022

Cellulose nanofibrils (CNF) based on wood pulp fibers are gained much attention as part of biocompatible hydrogels for biomedical applications such as tissue engineering scaffolds, biomedicine, and drug carrier. However, CNF hydrogels have relatively poor mechanical properties, impeding their applications requiring high mechanical integrity. In this work, we prepare 2,2,6,6-tetramethylipiperidin-oxyl (TEMPO) oxidated cellulose nanofibrils hydrogels mediated with metal cations, which form the metal-carboxylate coordination bonds for enhanced mechanical strength and toughness. We conduct the large amplitude oscillatory shear (LAOS) test and Live/dead cell assay for obtaining nonlinear viscoelastic parameters and cell viability, respectively. In particular, the cell proliferation and viability change depending on the type of metal salt, which also affected the rheological properties of the hydrogels.

• Applied Chemistry for Engineering
• /
• v.27 no.4
• /
• pp.380-385
• /
• 2016

Nanocelluloses, mainly cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC, i.e., defect-free, rod-like crystalline residues after acid hydrolysis of fibers), have been the subject of recent interest. Due to the presence of hydroxyl groups on the surface of nanocelluloses, their surfaces are reactive, making them suitable candidates for reinforcing materials for manufacturing polymer composites. In this study, CNF was used as a reinforcing material for manufacturing cement composites. CNF was prepared by TEMPO (2,2,6,6,-tetramethyl piperidine-1-oxyl radical) oxidation procedure combined with extensive homogenization and ultrasonication. Transmission electron microscopy (TEM) analysis of the suspension showed the width of CNF between 10 and 15 nm. The compressive strength of cement composites containing 0.5% CNF was comparable to that of conventional cement composites. On the other hand, the tensile and flexural strength were improved by 49.7% and 38.8%, respectively, compared to those of conventional cement composites. Also, at an ambient condition, the degree of self-shrinkage reduction reached to 18.9% in one day, followed by 5.9% in 28 days after molding.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.4
• /
• pp.483-490
• /
• 2014

The effect of microfibrillated cellulose (MFC) content and coupling agent (polymeric methylene diphenyl diisocyanate, pMDI) on the properties of MFC-reinforced polybutylene succinate (PBS) nanocomposite. With increasing MFC content, tensile strength and elastic modulus were increased. More than 1.5 times in tensile strength of PBS/MFC(70/30) nanocomposite was improved by the addition of pMDI (1 phr), compared to the nanocomposite without pMDI. This trend was being significant in nanocomposite with higher MFC content. Thermal stability of the nanocomposite was increased by the addition of pMDI. These improvements is considered to be due to the improvement of MFC dispersion and interfacial adhesion between MFC and PBS matrix.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.4
• /
• pp.376-384
• /
• 2014

This study investigated the effect of nanocellulose, such as microfibrillated cellulose (MFC) and cellulose nanocrystal (CNC), and aminated starch on tensile property and thermal stability of plasticized starch film. Glycerol (23 wt%) was used as a plasticizer and nanocelluloses of 1-30 parts per hundred parts of resin (phr) in the basis of plasticized starch were added. Tensile strength and elastic modulus increased with increasing nanocellulose addition amount, whereas elongation at break decreased. Tensile properties of MFC-reinforced starch film were higher than those of CNC-reinforced film. Optimum addition amount of aminated starch, which is commonly used for paper sizing, to improve tensile property of film, was found to be 5%. And 1% addition of aminated starch showed the best effect in the improvement of tensile property of the film. Thermal stability was improved with the addition of MFC to plasticized starch film with and without aminated starch.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2011.04a
• /
• pp.201-205
• /
• 2011

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2011.10a
• /
• pp.151-156
• /
• 2011

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.4
• /
• pp.302-309
• /
• 2013

The highly porous cellulosic aerogels were prepared by freeze-drying method using sodium hydroxide-urea aqueous solution in the process of dissolution, gelation, regeneration and organic solvent substitution. The structural characteristics of porous aerogel were analyzed using scanning electron microscopy and nitrogen adsorption apparatus. As a result, the dissolving pulp was completely dissolved, but filter papers and holocellulose were divided into two layers (dissolved and undissolved parts) in the process of centrifugation. The structure of aerogel from dissolved pulp showed porous pores in the surface and net-shaped network in the inner part. Aerogels from filter paper and holocellulose had the condensed porous network surface and the open-pore nano-fibril network inner structure. Undissolved form of fibers was observed in the aqueous solution of aerogel from holocellulose. The BET value ($S_{BET}$) of aerogel from dissolved pulp was ranged in 260~326 $m^2/g$, and it was decreased with the increase of concentration. Whereas, the $S_{BET}$ value of aerogel from filter paper (198~418 $m^2/g$) was increased with the increase of concentration. The $S_{BET}$ value of aerogel from holocellulose were 137 $m^2/g$ at 2% (w/w) of cellulose, and it was increased to maximum 401 $m^2/g$ at 4% (w/w) of cellulose. Then, it was decreased at 5% (w/w) of cellulose.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2011.10a
• /
• pp.365-372
• /
• 2011

• Applied Chemistry for Engineering
• /
• v.32 no.1
• /
• pp.110-116
• /
• 2021

In this work, the surface of hydrophilic cellulose nanofibrils (CNFs) was modified precisely by varying amounts of cetyltrimethylammonium bromide (CTAB) to produce CNF-based particle surfactants. We found that a critical CTAB density was required to generate amphiphilic CTAB-grafted CNF (CNF-CTAB). Compared to pristine CNF, CNF-CTAB was highly efficient at stabilizing oil-in-water Pickering emulsions. To evaluate their effectiveness as particle surfactants, the surface coverage of oil-in-water emulsion droplets was determined by changing the CNF-CTAB concentration in the aqueous phase. Furthermore, styrene-in-water stabilized by CNF-CTAB surfactants was thermally polymerized to produce CNF-stabilized polystyrene (PS) particles, offering a great potential for various applications including pharmaceuticals, cosmetics, and petrochemicals.