• Korea-Australia Rheology Journal
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• v.12 no.2
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• pp.135-141
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• 2000

The linear viscoelastic behavior of acrylonitrile-butadiene-styrene (ABS) polymers with different rubber content has been investigated in the frame of a linear viscoelastic model, which takes into account the inter-connectivity of the dispersed rubber particles. The model developed in our previous work has been shown to properly predict the low frequency plateau for the storage modulus, which is generally observed in polymer blends containing core-shell-type impact modifiers. In the present study, further experiments have been carried out on ABS polymers with different rubber content to verify the validity of our linear viscoelastic model. It has been found that our model describes quite properly the rheological behavior of ABS polymers with different rubber content, especially at low frequencies. The experimental data confirm that our model describes the rheological properties of rubber-modified thermoplastic polymers with strong adhesion at the particle/matrix interface more accurately than the Palierne model.

• Korean Journal of Materials Research
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• v.13 no.11
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• pp.725-731
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• 2003

The effect of organic processing parameters on the dispersion stability of the BaTiO$_3$-based dielectric particles and borosilicate glass particulate suspensions was investigated in a system where organic solvents, dispersant, binder and modifier were used as processing additives in a low temperature cofired ceramic fabrication processes. Two- and three-component organic solvents were used to disperse ceramic particles and it was found the better stability in the particulate suspension prepared in a bi-solvent, which was consists of toluene and ethanol in a non-azeotropic composition. The addition amount of organic additives had a great impact on dispersion in the present investigation. The flow curves of the suspensions prepared with binder and modifier were fitted according to the power-law equation, which indicates that the internal structure of the suspension could be disturbed under the applied shear stress. Finally, the LTCC green tapes were successfully tape-cast based upon the optimum formulation of LTCC suspension and its microstructure was compared with that of the hard-agglomerates.

• Clinical and Experimental Pediatrics
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• v.49 no.6
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• pp.581-588
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• 2006

Asthma is a chronic inflammation of the airway associated with increased bronchial hyperresponsiveness that leads to recurrent episodes of cough, wheezing, breathless, chest tightness. According the recent studies, repeated airway inflammation leads to structural changes so called 'airway remodeling' and associated with decreased pulmonary function. Airway remodeling begins form the early stage of asthma and the early diagnosis and management is very important to prevent airway remodeling. Medication for asthma can be classified into acute symptom reliever and chronic controller. Short acting beta2 agonist is a well-known reliever that reduced asthma symptoms within minutes. Controllers should be taken daily as a long-term basis to control airway inflammation. Inhaled corticosteroid(ICS) is the most effective controller in current use. However, in some patients ICS monotherapy is not sufficient to control asthma. In those cases, other medications such as long acting beta2 agonist, leukotriene modifier or sustained-release theophylline should be added to ICS, which called Add-on-Therapy. Combination inhaler devices are easy to use. Oral leukotriene modifier has a good compliance especially in children. Finally, as asthma is a chronic disease, the development of on-going partnership among health care professionals, the patients, and the patients' family is necessary for the effective management of asthma.

• Interdisciplinary Bio Central
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• v.4 no.4
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• pp.13.1-13.6
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• 2012

The advanced glycation endproducts receptor (AGER) is a multiligand signal transduction receptor. One of its ligands, S100b molecules activates vascular smooth muscle cells and endothelial cells via its receptor, thus triggering activation of signaling cascades and generation of cytokines and proinflammatory molecules. Ubiquitin-conjugating enzyme Ubc9 is an E2 conjugating enzyme that transfers the activated small ubiquitin-related modifier to protein substrates, and thus it plays a critical role in SUR-Mylation-mediated cellular pathways. Previous studies have shown that both AGE-R and Ubc9 play roles in diverse cellular signaling pathways. However, until recently, little attention has been paid to interactions between AGE-R and Ubc9. In this study, sequence database searches allowed us to identify a potential interaction motif between AGE-R and Ubc9. The subsequent biochemical and molecular biological analysis suggested that there may be specificity in AGE-R and Ubc9 complex signaling in atherosclerosis and cancer cells in a cell-type specific manner. Although the determinant for specificity in AGE-R and Ubc9 complex signaling in cancer cells and atherosclerosis is yet to be determined, this study provides the basis to develop a specific therapeutic application of AGE-R, SURM (small ubiquitin-related modifier)-1, and Ubc9 complex activation pathways in atherosclerosis, diabetes, cancer and inflammatory diseases.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.83-94
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• 1996

EMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and ethylhexyl metacrylate in acrylmonomer. To facilitate water emulsification, acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measure by GPC, and C.H.N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier[(PDCM-PED) water proof agent of cement for concrete in building construction] was prepared by blending of the guaternized acrylic copolymer syndisized above, sodium silicate, sodium gluconate and oleic acid emulsion. The result with prepared polymer dispersion of cement modifier was examined, and it was found that excellent waterprooffing effect ; Water permeability ratio is 0.50 under the water pressure of $100g/cm^2$ and 0.60 under $3kg/cm^2$, and water absorption ratio is $0.42{\sim}0.50$ and $1.0{\sim}1.02$ compressive strength ratio at mixed of water/PDCM-PED is 50 times.

• Elastomers and Composites
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• v.36 no.1
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• pp.3-13
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• 2001

To resolve environmental problem of waste tire and asbestos and also to capitalize the wastes, we developed a new kind of friction material using scrap tire, potassium hexatitanate, filler, and friction modifier in which rubber made a continuous phase. The material containing 5, 20, 10, 20phr of potassium hexatitanate, phenol, friction modifier, $BaSO_4$, respectively showed good friction properties, high and stable coefficient or friction, and low wear rate.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3805-3810
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• 2013

The surface modification of silica particles (SPs) was systemically conducted by the treatment of 0.1-10 wt % phenylsilanetriol (PST) on the basis of SPs used through two step processes: 1) the PST coating of SPs via evaporation under reduced pressure and 2) their thermal condensation leading to Si-O-Si bond formation via heating at $130^{\circ}C$. The evaluation of the modified SPs was conducted by the simple floating test on water and the measurement of the contact angle (CA) of water droplet on the 2-dimensional layer of modified SPs on slide glass. When PST was used about 2 wt % or above on the basis of SPs (about average size: 50 nm) used, the modified SPs were fully floated on the water and all dispersed into upper organic solvent layer after a shaking with the mixture of the water and benzene, indicating that the modified SPs have hydrophobic properties. The modified SPs were characterized by $^{29}Si$ MAS NMR and physicochemical properties including SEM, TEM, BET, adsorption/desorption isotherms, etc. were measured and compared each other in details. This research demonstrates that the organosilanetriol is a good modifier applicable for the surface modification of inorganic oxide particles using a low amount of modifier on the basis of oxide particles used.

• Carbon letters
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• v.20
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• pp.53-61
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• 2016

The reportedly synergistic effects of carbon nanotubes (CNTs) and graphene hybrids have prompted strong demand for an efficient modifier to enhance their dispersion. Here, we investigated the ability of poly(acrylonitrile) (PAN) to overcome the van der Waals interaction of multi-walled CNTs (MWCNTs) and graphene by employing a simple wrapping process involving ultrasonication and subsequent centrifugation of PAN/MWCNT/graphene solutions. The physical wrapping of MWCNTs and graphene with PAN was investigated for various PAN concentrations, in an attempt to simplify and improve the polymer-wrapping process. Transmission electron microscopy analysis confirmed the wrapping of the MWCNTs and graphene with PAN layers. The interaction between the graphitic structure and the PAN molecules was examined using proton nuclear magnetic resonance, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy. The obtained results revealed that the cyano groups of the PAN molecules facilitated adhesion of the PAN molecules to the MWCNTs and graphene for polymer wrapping. The resulting enhanced dispersion of MWCNTs and graphene was verified from zeta potential and shelf-life measurements.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.29-37
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• 2007

The effects of latex particle size, basis weight of base paper and coating color concentration on the printing quality of coated paper were investigated. Coating colors were prepared with five types of latexes having different particle sizes. Coated papers were produced with high solid coating colors and with low solid coating colors in a industrial coater, respectively. In high solid coating colors, rheology modifier was used and GCC content was high. It was concluded that, in order to control binder migration and hence print mottle, latex particle sizes shall be controlled as well as formation, sizing degree and roughness of basis paper.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.33-40
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• 2009

The use of the crumb rubber as an asphalt binder modifier may contribute to road maintenance and repair. The adhesion properties of the crumb rubber modified asphalt (CRMA) sealant have attracted interest due to brittle and adhesion failure of asphalt binders at low temperatures. In this study, the influence of a flexibilizer as a modifier for CRMA at low temperatures was investigated. Their properties were measured using the penetration, the softening point, the tensile and tensile adhesion tests at low temperature. The tensile adhesion strength and the strain of CRMAs were increased with increasing ductile deformation of the CR and the asphalt binder in the flexiblizer modified CRMAs. It was found that the flexibilizer concentration was an important factor for tensile and adhesion properties of CRMAs at low temperatures.