• Proceedings of the Korean Society of Rheology Conference
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• 2000.05a
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• pp.23-26
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• 2000

• Proceedings of the Korean Society of Rheology Conference
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• 2001.06a
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• pp.15-18
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• 2001

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.665-670
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• 2005

Nanocomposites of polypropylene with organically modified clays were compounded on a twin-screw extruder by two-step melt compounding of three components, i.e., polypropylene, maleic anhydride grafted polypropylene (PP-g-MA), and organically modified clay. The effect of PP-g-MA compatibilizers, including PH-200, Epolene-43, Polybond-3002, Polybond-3200, with a wide range of maleic anhydride (MA) content and molecular weight was examined. Morphologies of nanocomposites and their mechanical properties such as stiffness, strength, and impact resistance were investigated. X-ray diffraction patterns showed that the dispersion morphology of clay particles seemed to be determined in the first compounding step and the further dispersion of clays didn't occur in the second compounding step. As the ratio of PP-g-MA to clay increased, the clay particles were dispersed more uniformly in the matrix resin. As the dispersibility of clays was enhanced, the reinforcement effect of the clays increased, however impact resistance decreased.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.120-126
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• 2016

Eco-friendly acrylic resin/clay nanocomposites containing pristine montmorillonite (PM) or modified clays (30B and 25A) were prepared from acrylic and styrenic monomers using non-aqueous dispersion (NAD) polymerization. Effect of nanoclays on physical properties of polymerization product and resulting nanocomposites was investigated. In view of NAD particle stability, addition of nanoclay at the beginning of polymerization is proved to be good. Results of gel fraction, acid value and viscosity of the NAD product showed that nanocomposites containing clay 25A showed better physical properties than the ones with other clays. GPC results exhibit the increase in molecular weight and decrease in polydispersity index for the 25A nanocomposite. Increase in layer distance confirmed from XRD analysis showed good dispersion of 25A in the nanocomposite. Thermal and dynamic mechanical analysis showed that highest glass transition temperature and storage modulus for 25A nanocomposites. These results indicate that 25A nanoclay gives the best properties in the process of non-aqueous dispersion polymerization of acrylic resin/nanoclay nanocomposites.

• Elastomers and Composites
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• v.44 no.4
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• pp.455-465
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• 2009

In this study, Organo-montmorillonite(MMT) was synthesized by intercalation of various amine(Octylamine, Dodecylamine, Dimethyldodecylamine, Octadecylamine) compounds into layered silicate. Natural Rubber(NR)/MMT nanocomposites were prepared by reinforcement of Organo-MMT. X-ray diffraction(XRD) and Scanning electron microscope(SEM) were employed to characterize the layer distance of Organo-MMT and the morphology of the NR/MMT nanocomposites. The structures of the synthesized Organo-MMTs were analyzed by the measurement of FT-IR. Cure characteristics, surface free energy and mechanical properties such as tensile strength, modulus and hardness of NR/MMT nanocomposites were carefully studied by contact angle meter, ODR, UTM, and hardness tester. FT-IR analysis showed a insertion of the alkyl and amine chains into the interlayers of the MMT. It was shown that the cure time of the organo-MMT was more decreased than that of $Na^+$-MMT. Surface free energy and tensile strength of the NR/DDA-MMT nanocomposite were the highest. NR/ODA-MMT nanocomposite was the highest in hardness.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.352-353
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• 2003

Clay 분산 유/무기 나노복합재 제조기술은 실리케이트 층상구조의 점토광물을 나노 스케일의 시트상의 기본 단위로 박리(exfoliation)하여 고분자수지에 분산시킴으로써 범용 고분자의 낮은 기계적 물성의 한계를 엔지니어링 플라스틱 수준으로까지 올리고자 하는 것으로서, 기존의 무기 충진재 및 강화재의 입자크기(〉1 $\mu\textrm{m}$)를 나노 스케일까지 분산시켜 기존 무기물 충진 복합재의 단점을 한층 보완하는 것을 목표로 하고 있어 성능 및 원가 면에서 매우 유리한 방법으로 21세기의 복합재료 생산시장의 판도에 상당한 변화를 가져오게 할 수 있는 핵심기술이라 할 수 있다. (중략)

• Macromolecular Research
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• v.8 no.3
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• pp.120-124
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• 2000

Clay-dispersed nanocomposites have been prepared by simple melt-mixing of two components, styrenic polymers with different content of functional groups and two different organophilic clays (Cloisite(R) 25A and Cloisite(R)30A) with a twin screw extruder. Dispersibility of 10-$\AA$-thick silicate layers of clay in the hybrid was investigated by using an X-ray diffraction method and a transmission electron microscope. It was found that if the interaction force between intercalant and matrix polymer is attractive, the matrix polymer intercalates more rapidly into the gallery of silicate layers. The faster intercalation of matrix polymer leads to the better dispersibility of silicate layers in the matrix polymer.

• Elastomers and Composites
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• v.54 no.3
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• pp.201-208
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• 2019

Superabsorbent hydrogel (SAH) is a lightly crosslinked hydrophilic functional polymer material comprising a flexible chain structure, which can absorb and retain high amounts of water or aqueous fluids even under high pressure. Therefore, it is important to improve their characteristics such as absorption performance, residual monomer content, and water permeability. SAH nanocomposites were prepared using clay mineral as an inorganic filler and the influence of post-treatment processes such as quenching and aging process on their properties was studied. In addition, surface-crosslinking process was applied to improve the absorption performance associated with mechanical properties and water permeability. The structure of the SAH was characterized using attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction analysis, and scanning electron microscopy.

• Korea-Australia Rheology Journal
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• v.20 no.1
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• pp.27-34
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• 2008

Clay suspensions in liquid polymers exhibit a time-dependent behaviour that includes viscoelastic as well as thixotropic features. Because of the presence of interacting clay platelets, particulate networks can develop, which are broken down during flow and rebuild upon cessation of the flow. Here, the use of thixotropic techniques in probing flow-induced structures in nanocomposites is explored with data on a hectorite-poly(isobutylene) model system. By means of fast stress jump measurements the hydrodynamic contributions to the steady state stresses are determined as well as those caused by the stretching of the clay floes. Flow reversal measurements do not provide a clear indication of flow-induced anisotropy in the present case. The recovery of the clay microstructure upon cessation of flow is followed by means of overshoot and dynamic measurements. The development of a particulate network is detected by the appearance and growth of a low frequency plateau of the storage moduli. The modulus-frequency curves after various rest times collapse onto universal master curves, regardless of the pre-shear history or temperature. The scaling factors for this master curve are the crossover parameters. The crossover moduli are nearly a linear function of the crossover frequency, the relation being identical for recovery after shearing at different shear rates. This function depends, however, on temperature.

• Elastomers and Composites
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• v.41 no.4
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• pp.252-259
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• 2006

A new route for making rubber/clay nanocomposites was suggested based on skim natural rubber latex (SNRL), which is a protein rich by-product obtained during the centrifugal concentration of natural rubber (NR) latex. NR/acrylonitrile butadiene rubber (NBR) based nanocomposites were prepared from SNRL and NBR latex of 26 % acrylonitrile content by blending of aqueous dispersion of organoclay (OC) followed by coagulation, drying, mill mixing and vulcanization. X-ray diffraction(XRD) studies revealed that NR/NBR blend nanocomposites exhibited a highly intercalated and exfoliated structure, especially for NBR-rich blends. Dynamic mechanical studies showed that more compatible behavior was observed for NBR-rich blends. The 25/75 NR/NBR blend nanocomposite showed the best mechanical properties.