• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2395-2398
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• 2010

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.13-17
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• 2005

Potential for measuring mobile cadmium concentration in sandy soil using polymer magnetic beads with carboxyl groups was investigated. Experiments for extracting cadmium were performed with contaminated soils, de-ionized water and magnetic beads. In this neutral experimental condition, reacting cadmium with magnetic beads indicate total amount of cadmium that can be moved in soil. The results showed that the mobile fraction of cadmium in soil could be combined with magnetic beads in short time. After binding between cadmium and magnetic beads, the beads were separated from soil suspension by outer magnetic force. The bound cadmium was dissolved from magnetic beads by acid solutions, which were then analyzed by atomic absorption spectroscopy (AAS). This method can determine mobile heavy metals in sandy soil effectively than existing method which use pollutant chemicals to environments such as EDTA.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.444-445
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• 2008

• Macromolecular Research
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• v.15 no.4
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• pp.285-290
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• 2007

Ag nanoparticles were distributed onto polystyrene nanoparticle (PS-Ag) beads using two synthetic methodologies. In the first methodology, polystyrene (PS) beads were prepared via emulsion polymerization, with Ag nanoparticles subsequently loaded onto the surface of the PS beads. The polymerization of styrene was radiolytically induced in an ethanol (EtOH)/water medium, generating PS beads. Subsequently, Ag nanoparticles were loaded onto the PS beads via the reduction of Ag ions. The results from the morphological studies, using field emission transmission electron microscopy (FE-TEM), reveal the PS particles were spherical and nanosized, and the average size of the PS spherical particles decreased with increasing volume % of water in the polymerization medium. The size of the PS spherical particles increases with increasing radiation dose for the polymerization. Also, the amount of Ag nanoparticle loading could be increased by increasing the irradiation dose for the reduction of the Ag ions. In the second methodology, the polymerization of styrene and reduction of Ag ions were simultaneously performed by irradiating a solution containing styrene and Ag ions in an EtOH/water medium. Interestingly, the Ag nanoparticles were preferentially homogeneously distributed within the PS particles (not on the surface of the PS particles). Thus, Ag nanoparticles were distributed onto the surface of the PS particles using the first approach, but into the PS clusters of the particles via the second. The antimicrobial efficiency of a cloth coated with the Ag-PS composite nanoparticles was tested against bacteria, such as Staphylococcus aureus and Klebsiella pneumoniase, for 100 water washing cycles.

• Elastomers and Composites
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• v.35 no.1
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• pp.29-37
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• 2000

In this study as a basic research of the elastomer, we show the results of the behavior of the two different chain length polymers in the melt confined between two impenetrable planes. The cubic lattice simulations are conducted in the canonical ensemble with a method that is a combination of reptation and crackshaft bond flip motions. A total of 680 chains which are 544 short chains comprising 10 beads and 136 long chains comprising 160 beads were placed in 20 lattice layers. It was assumed that there is no energetic interactions between covalently connected beads. while all other neighbors will interact with a truncated 6-12 Lennard-Jones potential. From the analysis of the simulation results, it was shown that purely entropic effects caused the shorter chains to partition preferentially to the surface. We also showed that the center of mass density of the shorter chains shows maximum near the surface. This is the opposite phenomena when compared to that of the longer chains. However, the segments of the shorter and the longer chains did not display any significant changes in bond order.

• Polymer(Korea)
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• v.36 no.6
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• pp.761-767
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• 2012

The polycarbonate (PC)-based optical diffusers for direct-lit LED backlight unit were prepared by using extrusion compounding followed by compression molding process. The application of inorganic porous silica particles as a diffusing agent in addition to conventional poly(methyl methacrylate) (PMMA) beads was attempted, and the optical, thermal, and mechanical properties of the prepared diffusers were investigated. The morphological observations revealed that the diffusing agents could be uniformly dispersed in the PC matrix without agglomeration by high shear stress generated during extrusion process. The incorporation of the porous silica particles mixed with PMMA beads remarkably enhanced the luminance uniformity with respect to both location and view angle for the diffuser, while minimizing the reduction in the absolute luminance, as compared with the diffuser containing only PMMA beads. In addition, thermal and mechanical properties of the diffusers were shown to be improved upon addition of the porous silica particles.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1145-1153
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• 2015

PVC-Zeolite composite was prepared by immobilizing zeolite with polyvinyl chloride (PVC). The prepared PVC-Zeolite beads were characterized by using X-ray diffractometer (XRD), fourier transform infrared spectrometer (FTIR), thermo gravimetric analyzer (TGA), and scanning electron microscopy (SEM). The removal properties of Sr and Cs ions from aqueous solution were investigated in batch experiment. The removal efficiencies of Sr and Cs ions by the PVC-Zeolite beads were dependent on the initial pH of solution. The removal efficiencies sharply increased at below pH 4 and was kept constant at pH 4 or more. The adsorption kinetics of Sr and Cs ions by the PVC-Zeolite beads were fitted well by the pseudo-second-order model ($r^2$>0.99) more than pseudo-first-order model. The maximum adsorption capacities of Sr and Cs ions calculated from Langmuir isotherm model were 39.37 mg/g and 55.87 mg/g, respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.7.2-7.2
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• 2009

Nanoporous bioactive glass(NBG) ceramic with well interconnected pore structures were fabricated bytriblock copolymer templating and sol-gel techniques. Hierarchically porous BGbeads were also successfully synthesized by controlling the condition of solvent.The beads have hierarchically nano- and macro-pore structure with a sizesbetween several tens nanometers and several hundred micrometers. Both NBG andBG beads show superior bone-forming bioactivity and good in vitrobiodegradability. Biocompatibility both in vitro and in vivo were examed andwas revealed that it largely relies on the pore morphology as well ascomposition. Our synthetic process can be adapted for the purpose of preparingvarious bioceramics, which have excellent potential applications in the fieldof biomaterials such as tissue engineering and drug storage.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.247.1-247.1
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• 2003

Iron deficiency is the most common nutritional problem worldwide. Oral iron supplementation programs have failed because of noncompliance and gastrointestinal toxicity. The purpose of this study was to explore the possibility of alginate gel bead as an oral controlled release system of iron supplements and increase the stability of iron succinyl casein (ISC). Alginate beads containing ISC were prepared by the gelation of sodium alginate with calcium cations. The release profiles of ISC were investigated according to the concentration of polymer, the drug/sodium alginate ratio, the concentration and type of cation, curing time and pH of calcium chloride solution. (omitted)

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.449-455
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• 1986

Various polymer metal complexes have been synthesized from anhydrous $AlCl_3,\;FeCl_3,\;SbCl_5,\;SnCl_4\;and\;ZnCl_2$ with cation exchange resin in carbon disulfide solvent. The forms of the surfaces and sectioned beads of these polymer metal complexes have been observed using scanning electron probe microanalyzer. To examine the catalytic activity of polymer metal complexes, the esterification of various dibasic acids with alcohols have been carried out. Polymer metal complexes were found to be the effective catalyst for esterification of dibasic carboxylic acids.