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이지훈,Yulin Deng 한국고분자학회 2012 Macromolecular Research Vol.20 No.1
Cellulose nanowhisker-reinforced poly(vinyl alcohol) (PVA) nanofiber webs with different alignment degrees were successfully fabricated using an electrospinning technique. The morphology and mechanical properties of aligned and isotropic electrospun fiber webs were investigated. The relative alignment degree of electrospun fiber in the webs was analyzed using a fast Fourier transform method. Due to the different load transfer mechanisms,aligned PVA electrospun fiber webs show high modulus and tensile strength along the fiber direction compared with isotropic PVA electrospun fiber webs. Cellulose nanowhisker-reinforced PVA electrospun fiber webs show increased mechanical properties for both the aligned electrospun webs and the isotropic electrospun webs. Experiment results indicate that cellulose nanowhiskers have a more significant reinforcement effect for the aligned webs than the isotropic webs.
Characterization of Electrospun Nanofibers of Cellulose Nanowhisker/Polyvinyl Alcohol Composites
Mijung Cho,Byung Dae Park,John F. Kaclla 한국목재공학회 2012 목재공학 Vol.40 No.2
Cellulose nanowhisker (CNW) isolated from hardwood bleached kraft pulp (1-W-BKP) using sulfuric acid hydrolysis was suspended in polyvinyl alcohol (PVA) and electrospun into composites nanofibers. Transmission electron microscopy (TEM) revealed the CNW to be rod-like, approximately of 16.1 4.6 nm wide and 194 ± 61 nm long, providing an aspect ratio of about 12, with a particle size distribution range of 662.2 + 301.2 nm. Uniform and high quality CNW/PVA composite nanofibers were successfully manufactured by the electrospinning method. As the CNW loading increases, the viscosity of CNW/PVA solutions shows a minimum at 1% CNW level which subsequently results in the smallest diameter (193 nm) of electrospun nanofibers. The average diameter of the nanofibers increased up to 284 nm with increasing CNW loading. These results suggest that the electrospinning method provides a great potential of manufacturing consistent and reliable nanofibers from CNW/PVA solution for the formation of scaffolds with potentials in future application.
Oun, Ahmed A.,Rhim, Jong-Whan Elsevier 2017 Carbohydrate polymers Vol.169 No.-
<P><B>Abstract</B></P> <P>Chitin nanowhiskers (ChNW) were isolated and used for the synthesis of hybrid ChNW/ZnO-Ag NPs. The hybrid nanoparticles were used for the preparation of multifunctional carboxymethyl cellulose (CMC) films. A ChNW was needle shape with the width of 8–40nm, the length of 150–260nm, and crystallinity index of 93.6%. The ZnO-Ag NPs were spherical with the diameter of 10.5–16.2nm. STEM, EDX, XRD, and UV–vis analyses confirmed the formation of ZnO-Ag NPs on the surface of ChNW. The thermal stability of ChNW was increased by incorporation of ZnO-Ag NPs. A CMC-based nanocomposite film incorporated with 5wt% of ChNW/ZnO-Ag NPs was homogeneous and showed the high UV-barrier property. The tensile strength (TS) and elastic modulus (E) of the composite film increased by 18–32% and 55–100%, respectively, while the elongation at break (EB) decreased by 23–33%. CMC composite films showed strong antibacterial activity against <I>E. coli</I> and <I>L. monocytogenes</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hybrid ZnO-Ag nanoparticles were prepared. </LI> <LI> The ZnO-Ag NPs were formed on the surface of the chitin nanowhiskers (ChNW). </LI> <LI> The hybrid NPs were used for the preparation of CMC-based multifunctional nanocomposite films. </LI> <LI> Tensile strength, elastic modulus, water vapor barrier, and thermal stability properties of the nanocomposite films increased significantly. </LI> <LI> The nanocomposite films exhibited strong antibacterial activity against both Gram<SUP>+</SUP> and Gram<SUP>−</SUP> bacteria. </LI> </UL> </P>
Surface Modification of Cellulose Nanowhiskers and Their Reinforcing Effect in Polylactide
이주형,김성훈,박상호 한국고분자학회 2014 Macromolecular Research Vol.22 No.4
The aim of this study was to improve the dispersability of the cellulose nanowhiskers (CNW) in the nonpolarenvironment, and to fabricate its biocomposites. The acetylated cellulose nanowhiskers (ACNs) were preparedby introducing the acetyl groups onto the cellulose surfaces. The biocomposites were prepared by incorporating 1,2 and 3 wt% of the ACN into the polylactide (PLA) matrix by using a solution casting method. From the morphologicalanalysis, it was found that the ACN was dispersed well in PLA matrix because of the surface blocking effectby acetyl groups on the cellulose surface, which led to decrease of surface polarity. Moreover, the ACN showedenhancing effects on the tensile properties, thermal stability, dimensional stability and dynamic mechanical propertiesof the PLA composites. The ACN promoted crystallization behavior, resulting in an increase in crystallinity forthe PLA/CNW composites. From the results of this work, the dispersability of the cellulose can be improved significantlyby surface modification, and it can maximize the reinforcing potential of cellulose for the biopolymers.
High Performance of NanoCellulose/Nanochitin Coating Polypropylene Film for Food Packaging Materials
Seunghyeon LEE,Dongsoo HWANG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
In food packaging industry, it is important to possess barrier properties which prevent oxygen gas and water vapor. In general, aluminum coated polypropylene films are used because aluminum has a good gas barrier ability. However, this film is difficult to reuse and generate harmful particle when finally incinerated. In this study, we made a renewable food packaging film using the two most abundant biorenewable resources, cellulose and chitin. The structure of this film is simply made by stacking TEMPO cellulose nanofibers and Chitin nanowhiskers on polypropylene, and coating layers can sufficiently prevent oxygen gas and water vapor permeation. Compared with pristine pp, oxygen gas and water vapor permeability were significantly reduced from 1118 to 13.10㏄ m-2day-1 and from 2.43 to 2.13g m-2day-1, respectively. Furthermore, it has high transparency and antibacterial effect, so it can be expected as a new renewable food packaging material.
Preparation of Cellulose Nanowhiskers and Their Reinforcing Effect in Polylactide
이주형,박상호,김성훈 한국고분자학회 2013 Macromolecular Research Vol.21 No.11
Cellulose nanowhiskers (CNW) were isolated from microcrystalline cellulose (MCC) using acid hydrolysis and ultrasonication. Polylactide (PLA) composites were prepared by incorporating CNW (0.1 and 0.5 wt%) into a PLA matrix and casting the composite films. To investigate the effects of the CNW as reinforcement in the PLA composites,analyses of rheological properties, thermal stability, thermal behavior, and mechanical properties were performed. In rheological analysis, complex viscosity of the PLA/CNW solutions in CHCl3 was decreased with an increase in frequency and the storage modulus and loss tangent were increased with filler loading. Despite filler loading on the PLA matrix, transmittance was decreased slightly. Thermal stability was decreased with CNW loading. The nanocellulose filler did not affect glass transition or melting temperature; however, it promoted crystallization,resulting in an increase in crystallinity for the PLA composites. The tensile strength and tensile modulus of the PLA composite films increased with a rise of CNW contents. These results suggest that high performance PLA bionanocomposites with high transparency can be obtained by adding uniformly dispersed small amount of the CNW.
셀룰로스 나노휘스커 강화 셀룰로스 아세테이트 복합재료의 특성
조현은,송영한,김형섭,Cho, Hyun Eun,Song, Younghan,Kim, Hyungsup 한국섬유공학회 2014 한국섬유공학회지 Vol.51 No.6
Recently, nanomaterials obtained from biomass have gained attention due to their function and sustainability. Among bio-nanomaterials, cellulose nanowhisker (CNW) is one of the most potential materials for reinforcement of bioplastics due to its superior mechanical properties, biodegradability, and high aspect ratio. In the study, cellulose acetate composite was produced using CNW obtained under different conditions. There was a significant increase in the initial modulus of the composite with increasing CNW content, but there was no impact on the thermal stability.