• Steel and Composite Structures
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• v.46 no.1
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• pp.15-31
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• 2023

Organic solar cells utilized natural polymers to convert solar energy to electricity. The demands for green energy production and less disposal of toxic materials make them one of the interesting candidates for replacing conventional solar cells. However, the different aspects of their properties including mechanical strength and stability are not well recognized. Therefore, in the present study, we aim to explore the chaotic responses of these organic solar cells. In doing so, a specific type of organic solar cell constructed from layers of material with different thicknesses is considered to obtain vibrational and chaotic responses under different boundaries and initial conditions. A square plate structure is examined with first-order shear deformation theory to acquire the displacement field in the laminated structure. The bounding between different layers is considered to be perfect with no sliding and separation. On the other hand, nonlocal elasticity theory is engaged in incorporating the structural effects of the organic material into calculations. Hamilton's principle is adopted to obtain governing equations with regard to boundary conditions and mechanical loadings. The extracted equations of motion were solved using the perturbation method and differential quadrature approach. The results demonstrated the significant effect of relative glass layer thickness on the chaotic behavior of the structure with higher relative thickness leading to less chaotic responses. Moreover, a comprehensive parameter study is presented to examine the effects of nonlocality and relative thicknesses on the natural frequency of square organic solar cell structure.

• Journal of the Korean Ceramic Society
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• v.44 no.2 s.297
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• pp.71-78
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• 2007

A [TEACOOH]-Montmorillonite intercalations complex obtained from Na-Montmorillonite and 10-Carboxy-n-triethylammonium bromide was used to attempt the polymerization of ${\varepsilon}$-caprolactone between the layer spaces of the intercalations complex to achieve Montmorillonite-Polycaprolactone nanocomposites in which the inorganic material (montmorillonite) is chemically combined with the organic polymer (polycaprolactone). The results of X-ray-, IR-, and TEM-analyses for samples obtained after polymerization showed that a polycondensation reaction was successfully produced. For a more precise investigation of the polymeric reaction products the polymerized products were separated from the silicate layers and analyzed with an IR-spectrometer. A comparison of the results of the IR-analyses of the separated polymer with that of the polymer synthesized by the reaction of ${\varepsilon}$-caprolactone with only the organic cation and without montmorillonite showed that the two obtained polymers are the same compound.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.18-18
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• 2003

Natural clays are composed of oxide layers whose thickness is about 1nm and cations existing between the layers. A number of these layers makes primary particles with a height of about 8∼10nm and these primary particles make aggregates with a size of about 0.1∼10$\mu\textrm{m}$. When layered silicate was made to be organophilic, by exchanging the interlayer cations with organic cationic molecules, the matrix polymer can penetrate between the layers to give a nanocomposite, where 1nm-scal clay layers exist separately in a continuous polymer matrix. These nanostructured hybrid organic-inorganic composites have attracted the great interest of researchers over the last 10 years. They exhibit improved performance properties compared with conventional composites, because their unique phase morphology by layer intercalation or exfoliation maximizes interfacial contact between the organic and inorganic phases and enhances interfacial properties. Since the advent of nylon-6/montmorillonite nanocomposite developed by Toyota Motor Co., the studies on layered silicate-polymer nanocomposites have been successfully extended to other polymer systems. They greatly improved the thermal, mechanical, barrier, and even the flame-retardant properties of the polymers.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.224-231
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• 2005

The polymerization of $\varepsilon-caprolactone$ in the layers of the [DEACOOH]-Montmorillonite intercalations complex was attempted using 10-Carboxy-n-decyldimethylethylammonium bromide and Na-Montmorillonite to achieve [DEACOOH]-Polycaprolactone-Montmorillonite in which the inorganic material (montmorillonite) and the organic material (polycaprolactone) are chemically linked each other. The results of X-ray- and IR-analysis for the samples obtained after polymerization showed that the polymerization reaction has been successfully accomplished. In order to study the polymeric reaction products more precisely we have separated the polymerized product from the silicate layers and analyzed it with X-ray diffractometer, IR-spectrometer and TEM. The comparison of the results of X-ray- and IR-analysis for the separated polymer with them for the polymer which was synthesized by the reaction of $\varepsilon-caprolactone$ only with the organic cation without montmorillonite showed that the obtained both polymers are the same compounds.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.368-368
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• 2006

Micro-molded parts can be defined as parts with microgram weight, parts with micro-structured surface, and parts with micro-precision. In this study, various micro-scale molded parts for various polymers were produced by using a precision micro-molding machine. Molded parts with nano-structure surface were also produced to analyze the effect of molding conditions on replication of surface pattern and higher-order structure development of molded parts. Replication of molded parts was influenced by material properties, molding conditions and size of surface pattern. Higher-order structure of molded parts was investigated by using polarized microscope. Skin-shear-core regions inside the molded parts were observed and shear region affected to surface replication.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.329-329
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• 2006

Various new active ester monomers based on (meth)acrylates and 4-vinylbenzoic acid have been prepared. Investigation of the controlled radical polymerization behavior of the respective monomers resulted in excellent polymerization control, thus, opening synthetic routes to reactive block copolymers. Polymer analogous reactions with amines yielded functional polymers. In the case of the copolymer poly(N-isopropylacrylamide-co-acetone oxime acrylate) a lower critical solution temperature could be measured at $52^{\circ}C$. Thus, the reactive copolymer features two characters: reactive AND stimuliresponsive behavior.

• Macromolecular Research
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• v.8 no.5
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• pp.224-230
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• 2000

Molecular mechanics technique has been used for finding energy-minimized conformation to understand the mechanism of yielding of glassy polymers in atomistic level. As a model polymer, amor- phous isotactic polypropylene (iPP) was generated by molecular mechanics and molecular dynamics methods. The stress-strain cone was successfully obtained by using molecular mechanics technique. The torsional angle distribution showed no significant change during extension, although the torsional angles of certain bonds in polymer backbone changed more largely than other bonds. No significant change in the van der Waals interaction is observed at yielding point, whereas the torsional angle energy starts to decrease at yield strain.

• Fibers and Polymers
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• v.5 no.2
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• pp.105-109
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• 2004

The synthesis of titanium dioxide nanofibers with 200-300nm diameter was presented. The new inorganic-organic hybrid nanofibers were prepared by sol-gel processing and electrospinning technique using a viscous solution of titanium isopropoxide (TiP)/poly(vinyl acetate) (PVAc). Pure titanium dioxide nanofibers were obtained by high temperature calcination of the inorganic-organic composite fibers. SEM, FT-IR, and WAXD techniques were employed to characterize these nanofibers. The titanium dioxide nanostructured fibers have rougher surface and smaller diameter compare with PVAc/TiP composite nanofibers. The anatase to rutile phase transformation occurred when the calcination temperature was increased from $600^{\circ}C$ to $1000^{\circ}C$.

• Fibers and Polymers
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• v.3 no.3
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• pp.103-108
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• 2002

The viscosity effect of matrix polymer on melt exfoliation behavior of an organoclay in poly($\varepsilon$-caprolactone) (PCL) was investigated. The viscosity of matrix polymer was controlled by changing the molecular weight of poly($\varepsilon$-eaprolactone), the processing temperature, and the rotor speed of a mini-molder. Applied shear stress facilitates the diffusion of polymer chains into the gallery of silicate layers by breaking silicate agglomerates down into smaller primary particles. When the viscosity of PCL is lower, silicate agglomerates are not perfectly broken into smaller primary particles. At higher viscosity, all of silicate agglomerates are broken down into primary particles, and finally into smaller nano-scale building blocks. It was also found that the degree of exfoliation of silicate layers is dependent upon not only the viscosity of matrix but thermodynamic variables.

• Journal of the Korean Ceramic Society
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• v.43 no.4 s.287
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• pp.207-212
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• 2006

[ ${\varepsilon}-caprolactam$ ] was polymerized in the layers of the [DEACOOH]-Montmorillonite intercalations complex at high temperatures ranging from 250% to 260% formed from Na-Montmorillonite and 10-Carboxy-n-decyldimethylethylammonium bromide to achieve [DEACOOH]-Polycaprolactam-Montmorillonite, in which an inorganic polymer (montmorillonite) is chemically combined with an organic polymer (polycaprolactam). The results of X-ray and IR analyses for the samples obtained after polymerization showed that the polymerization reaction was successfully accomplished. For the purpose of studying the polymeric reaction product more precisely, the polymerized product was separated from the silicate layers and analyzed with an X-ray diffractometer and an IR-spectrometer. A comparison of the results of the X-ray and IR analyses of the separated polymer and the polymer that was synthesized by the reaction of ${\varepsilon}-caprolactam$ solely with the organic cation without montmorillonite showed that the obtained both polymers are identical compounds.