• Title/Summary/Keyword: Polymeric material

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Screening of Biodegradable Function of Indigenous Ligno-degrading Mushroom Using Dyes

  • Jang, Kab-Yeul;Cho, Soo-Muk;Seok, Soon-Ja;Kong, Won-Sik;Kim, Gyu-Hyun;Sung, Jae-Mo
    • Mycobiology
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    • v.37 no.1
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    • pp.53-61
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    • 2009
  • The process of biodegradation in lingo-cellulosic materials is critically relevant to biospheric carbon. The study of this natural process has largely involved laboratory investigations, focused primarily on the biodegradation and recycling of agricultural by-products, generally using basidiomycetes species. In order to collect super white rot fungi and evaluate its ability to degrade lingo-cellulosic material, 35 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye. In the laccase enzymatic analysis chemical test, 33 white rot fungi and 2 brown rot fungi were identified. The degradation ability of polycyclic aromatic hydrocarbons (PAHs) according to the utilized environmental conditions was higher in the mushrooms grown in dead trees and fallen leaves than in the mushrooms grown in humus soil and livestock manure. Using Poly-R 478 dye to assess the PAH-degradation activity of the identified strains, four strains, including Agrocybe pediades, were selected. The activities of laccase, MnP, and Lip of the four strains with PAH-degrading ability were highest in Pleurotus incarnates. 87 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye on solid media. Using Poly-R 478 dye to assess the PAHdegrading activity of the identified strains, it was determined that MKACC 51632 and 52492 strains evidenced superior activity in static and shaken liquid cultures. Subsequent screening on plates containing the polymeric dye poly R-478, the decolorization of which is correlated with lignin degradation, resulted in the selection of a strain of Coriolus versicolor, MKACC52492, for further study, primarily due to its rapid growth rate and profound ability to decolorize poly R-478 on solid media. Considering our findings using Poly-R 478 dye to evaluate the PAH-degrading activity of the identified strains, Coriolus versicolor, MKACC 52492 was selected as a favorable strain. Coriolus versicolor, which was collected from Mt. Yeogi in Suwon, was studied for the production of the lignin-modifying enzymes laccase, manganese-dependent peroxidase (MnP), and lignin peroxidase (LiP).

Electrodeposition onto the Surface of Carbon Fiber and Its Application to Composites (II) - CFRC with MVEMA and EMA Interphase - (탄소섬유 표면에의 고분자 전착과 복합재료 물성 (II) - MVEMA 및 EMA 계면상을 갖는 탄소섬유 복합재료 -)

  • Kim, Minyoung;Kim, Jihong;Bae, Jongwoo;Kim, Wonho;Hwang, Byungsun;Choi, Youngsun
    • Applied Chemistry for Engineering
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    • v.10 no.3
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    • pp.336-342
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    • 1999
  • Various surface treatment techniques can be applied onto the surface of carbon fibers to increase interlaminar shear strength (ILSS). In a commerciaI treatment, first, surface of carbon fiber was oxidized, after that, a sizing agent was coated to improve handleability and adhesion to the matrix. Carbon fiber reinforced composites (CFRC) which is made of these fibers show excellent ILSS but show low vaIues of impact strength In this study, reactive and ductile interphase was introduced between fiber and matrix to increase both the ILSS and impact strength. By using electric conductivity of carbon fibers, flexible polymers which have ionizable group, i.e., MVEMA and EMA, were coated onto the surface (oxidized) of carbon fiber by the technique of electrodeposition. ILSS and impact strength of composites were evaluated according to the surface treatments, i.e., commercial sizing treatment, interphase introduction, and without sizing treatment. Izod impact strength and ILSS of CFRC were simultaneously improved in thc thickness range of $0.08{\sim}0.12{\mu}m$ of MVEMA interphase. Water resistance of the composites was decreased by introducing MVEMA interphase.

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Manufacture of Wood Veneer-Bamboo Zephyr Composite Board: II. Effect of Manufacturing Conditions on Properties of Composite Board (목재 단판-대나무 제퍼 복합보드 제조: II. 복합보드의 성능에 미치는 제조조건의 영향)

  • Roh, Jeang Kwan
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.6
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    • pp.108-117
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    • 2007
  • This research was performed to investigate the feasibility of bamboo as a raw material for the manufacture of plywood. Wood veneer-bamboo zephyr composite boards (WBCB) were manufactured using keruing (Dipterocarpus sp.) veneers and hachiku bamboo (Phyllostacbys nigra var. henonis Stapf) using various adhesives, and the effect of the method and amount of resin spread on the mechanical properties of the composites were investigated. The WBCB manufactured using polymeric isocyanate (PMDI) showed the best mechanical properties, followed by phenol-formaldehyde resin (PF), phenol-melamine-formaldehyde resin, urea-melamine-formaldehyde resin, and urea-formaldehyde resin. However, considering the operation feasibility as well as mechanical properties, PF resin proved to be the appropriate adhesive for the practical purpose. As the amount of resin spread increased, the mechanical properties of 5-ply WBCB with 12 mm thicknesses manufactured using PF resin tended to increase, and more failure occurred at the interface between veneer and bamboo zephyr than at the interface among bamboo zephyrs. This result suggests that penetration of resin into bamboo zephyr could be the important factor. In this research, the appropriate amount of resin amount was $320g/m^2$. 5-ply WBCBs were manufactured using various methods of resin spread but the effect of the methods on the mechanical properties showed no little difference, which meant that the method of resin spread could be chosen considering the manufacturing conditions and operation feasibility.

Self-healing Elastomers As Dream Smart Materials (꿈의 스마트 재료로서 자기치유 탄성체)

  • Kim, Il;Shin, Nam-Ho;Jo, Jung-Kyu;Hur, A-Young;Li, Haiqing;Ha, Chang-Sik
    • Elastomers and Composites
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    • v.44 no.3
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    • pp.196-208
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    • 2009
  • Sophisticated polymeric materials with 'responsive' properties are beginning to reach the market. The use of reversible, noncovalent interactions is a recurring design principle for responsive materials. Recently developed hydrogen-bonding units allow this design principle to be taken to its extreme. Supramolecular polymers, where hydrogen bonds are the only force keeping the monomers together, form materials whose (mechanical) properties respond strongly to a change in temperature or solvent. In this review, we describe some examples of hydrogen-bonded supramolecular polymers that can be utilized for self-healing materials. Synthesis of a rubber-like material that can be recycled might not seem exciting. But one that can also repeatedly repair itself at room temperature, without adhesives, really stretches the imagination. Autonomic healing materials respond without external intervention to environmental stimuli in a nonlinear and productive fashion, and have great potential for advanced engineering systems.

Coupled Analysis with Digimat for Realizing the Mechanical Behavior of Glass Fiber Reinforced Plastics (유리섬유 강화 플라스틱의 역학적 거동 구현을 위한 Digimat와의 연성해석 연구)

  • Kim, Young-Man;Kim, Yong-Hwan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.6
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    • pp.349-357
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    • 2019
  • Finite element method (FEM) is utilized in the development of products to realistically analyze and predict the mechanical behavior of materials in various fields. However, the approach based on the numerical analysis of glass fiber reinforced plastic (GFRP) composites, for which the fiber orientation and strain rate affect the mechanical properties, has proven to be challenging. The purpose of this study is to define and evaluate the mechanical properties of glass fiber reinforced plastic composites using the numerical analysis models of Digimat, a linear, nonlinear multi-scale modeling program for various composite materials such as polymers, rubber, metal, etc. In addition, the aim is to predict the behavior of realistic polymeric composites. In this regard, the tensile properties according to the fiber orientation and strain rate of polybutylene terephthalate (PBT) with short fiber weight fractions of 30wt% among various polymers were investigated using references. Information on the fiber orientation was calculated based on injection analysis using Moldflow software, and was utilized in the finite element model for tensile specimens via a mapping process. LS-Dyna, an explicit commercial finite element code, was used for coupled analysis using Digimat to study the tensile properties of composites according to the fiber orientation and strain rate of glass fibers. In addition, the drawbacks and advantages of LS-DYNA's various anisotropic material models were compared and evaluated for the analysis of glass fiber reinforced plastic composites.

Synthesis, Morphology and Permeation Properties of poly(dimethyl siloxane)-poly(1-vinyl-2-pyrrolidinone) Comb Copolymer (폴리디메틸실록산-폴리비닐피롤리돈 빗살 공중합체 합성, 모폴로지 및 투과성질)

  • Patel, Rajkumar;Park, Jung Tae;Park, Min Su;Kim, Jong Hak
    • Membrane Journal
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    • v.27 no.6
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    • pp.499-505
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    • 2017
  • The increasing number of natural disasters resulting from anthropogenic greenhouse gas emissions has prompted the development of a gas separation membrane. Carbon dioxide ($CO_2$) is the main cause of global warming. Organic polymeric membranes with inherent flexibility are good candidates for use in gas separation membranes and poly(dimethyl siloxane)(PDMS) specifically is a promising material due to its inherently high $CO_2$ diffusivity. In addition, poly(vinyl pyrrolidine)(PVP) is a polymer with high $CO_2$ solubility that could be incorporated into a gas separation membrane. In this study, poly(dimethyl siloxane)-poly(vinyl pyrrolidine)(PDMS-PVP) comb copolymers with different compositions were synthesized under mild conditions via a simple one step free radical polymerization. The copolymerization of PDMS and PVP was characterized by FTIR. The morphology and thermal behavior of the produced polymers were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Composite membranes composed of PDMS-PVP on a microporous polysulfone substrate layer were prepared and their $CO_2$ separation properties were subsequently studied. The $CO_2$ permeance and $CO_2/N_2$ selectivity through the PDMS-PVP composite membrane reached 140.6 GPU and 12.0, respectively.

Improved Dissolution and Characterization of Solid Dispersed Atorvastatin Calcium (아토르바스타틴 칼슘 고체분산체의 특성화 및 용출율 개선)

  • Lee, Jun-Hee;Ku, Jeong;Park, Jung-Soo;Park, Jong-Hak;Ahn, Sik-Il;Mo, Jong-Hyun;Kim, Yun-Tae;Rhee, John-M.;Lee, Hai-Bang;Khang, Gil-Son
    • Journal of Pharmaceutical Investigation
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    • v.38 no.2
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    • pp.111-117
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    • 2008
  • To overcome the solubility of poorly water-soluble drug, the formation of solid dispersion using a spray-dryer with polymeric material, that can potentially enhance the dissolution rate extend of drug absorption was considered in this study. $Eudragit^{(R)}$ E100 as carrier for solid dispersion is acrylate copolymer that soluble in acidic buffer solutions (below pH 5.0). It was used to increase dissolution of atorvastatin calcium as a water-insoluble drug in acidic environments. In this study, a spray-dryer was used to prepare solid dispersion of atorvastatin calcium and $Eudragit^{(R)}$ E100 for purpose of improving the solubility of drug. Atorvastatin calcium and $Eudragit^{(R)}$ E100 were dissolved in ethanol and spray-dryed. DSC and XRD were used to analyze the crystallinity of the sample. It was found that atorvastatin calcium is amorphous in the $Eudragit^{(R)}$ E100 solid dispersion. FT-IR was used to analyze the salt formation by interaction between atorvastatin calcium and $Eudragit^{(R)}$ E100. Comparative dissolution study exhibited better dissolution characteristics than the commercial drug ($Lipitor^{(R)}$) as control. The dissolution rate of atorvastatin calcium was markedly increased in solid dispersion system in simulated gastric juice (pH 1.2). This study proposed that this solid dispersion system improved the bioavailability of poorly water-soluble atorvastatin calcium.

Propylene/Nitrogen Separation Membranes Based on Amphiphilic Copolymer Grafted from Poly(1-trimethylsilyl-1-propyne) (양친성 고분자가 그래프팅된 Poly(1-trimethylsilyl-1-propyne) 기반의 프로필렌/질소 분리막)

  • Park, Cheol Hun;Lee, Jae Hun;Park, Min Su;Kim, Jong Hak
    • Membrane Journal
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    • v.29 no.2
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    • pp.88-95
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    • 2019
  • Hydrocarbons containing carbon double bonds are generally called olefins and it is extensively used in petro-chemical industry as essential base material. Especially, olefins are essential in polymer synthesis and thus the effective separation and purification of olefins from gas mixture are very important and it gives significant positive effect on the future industrial development. In this study, we fabricated polymeric composite membrane based on poly(1-trimethylsilyl-1-propyne) (PTMSP) for propylene/nitrogen separation and enhancement of its separation performance by grafting amphiphilic copolymer. Furthermore, to accelerate facilitated transport for propylene molecules, Ag salt ($AgBF_4$) and ionic liquid ($EMIM-BF_4$) was incorporated to polymer composite membranes. The neat PTMSP membrane exhibited extremely high gas permeance and low gas selectivity due to its high free volume. To address this issue, PTMSP was grafted with poly(oxyethylene glycol methacrylate) (POEM) and poly(ethylene glycol) behenyl ether methacrylate (PEGBEM). Additionally, the additives such as $AgBF_4$ and $EMIM-BF_4$ further increased the propylene permeance, resulting in increment of propylene/nitrogen selectivity.

Automated Inspection System for Micro-pattern Defection Using Artificial Intelligence (인공지능(AI)을 활용한 미세패턴 불량도 자동화 검사 시스템)

  • Lee, Kwan-Soo;Kim, Jae-U;Cho, Su-Chan;Shin, Bo-Sung
    • Journal of the Korean Society of Industry Convergence
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    • v.24 no.6_2
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    • pp.729-735
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    • 2021
  • Recently Artificial Intelligence(AI) has been developed and used in various fields. Especially AI recognition technology can perceive and distinguish images so it should plays a significant role in quality inspection process. For stability of autonomous driving technology, semiconductors inside automobiles must be protected from external electromagnetic wave(EM wave). As a shield film, a thin polymeric material with hole shaped micro-patterns created by a laser processing could be used for the protection. The shielding efficiency of the film can be increased by the hole structure with appropriate pitch and size. However, since the sensitivity of micro-machining for some parameters, the shape of every single hole can not be same, even it is possible to make defective patterns during process. And it is absolutely time consuming way to inspect all patterns by just using optical microscope. In this paper, we introduce a AI inspection system which is based on web site AI tool. And we evaluate the usefulness of AI model by calculate Area Under ROC curve(Receiver Operating Characteristics). The AI system can classify the micro-patterns into normal or abnormal ones displaying the text of the result on real-time images and save them as image files respectively. Furthermore, pressing the running button, the Hardware of robot arm with two Arduino motors move the film on the optical microscopy stage in order for raster scanning. So this AI system can inspect the entire micro-patterns of a film automatically. If our system could collect much more identified data, it is believed that this system should be a more precise and accurate process for the efficiency of the AI inspection. Also this one could be applied to image-based inspection process of other products.

An accurate analytical model for the buckling analysis of FG-CNT reinforced composite beams resting on an elastic foundation with arbitrary boundary conditions

  • Aicha Remil;Mohamed-Ouejdi Belarbi;Aicha Bessaim;Mohammed Sid Ahmed Houari;Ahmed Bouamoud;Ahmed Amine Daikh;Abderrahmane Mouffoki;Abdelouahed Tounsi;Amin Hamdi;Mohamed A. Eltaher
    • Computers and Concrete
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    • v.31 no.3
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    • pp.267-276
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    • 2023
  • The main purpose of the current research is to develop an efficient two variables trigonometric shear deformation beam theory to investigate the buckling behavior of symmetric and non-symmetric functionally graded carbon nanotubes reinforced composite (FG-CNTRC) beam resting on an elastic foundation with various boundary conditions. The proposed theory obviates the use to shear correction factors as it satisfies the parabolic variation of through-thickness shear stress distribution. The composite beam is made of a polymeric matrix reinforced by aligned and distributed single-walled carbon nanotubes (SWCNTs) with different patterns of reinforcement. The material properties of the FG-CNTRC beam are estimated by using the rule of mixture. The governing equilibrium equations are solved by using new analytical solutions based on the Galerkin method. The robustness and accuracy of the proposed analytical model are demonstrated by comparing its results with those available by other researchers in the existing literature. Moreover, a comprehensive parametric study is presented and discussed in detail to show the effects of CNTs volume fraction, distribution patterns of CNTs, boundary conditions, length-to-thickness ratio, and spring constant factors on the buckling response of FG-CNTRC beam. Some new referential results are reported for the first time, which will serve as a benchmark for future research.