• Bulletin of the Korean Chemical Society
• /
• v.23 no.11
• /
• pp.1616-1622
• /
• 2002

If the surfaces of vesicles are chemically modified so that they can be dispersed in organic solvents, the application of vesicular colloids may be expanded. A polymerizable surfactant (BDAC) and nonpolymerizable bipolar surfactant (BPAS) were synthesized in multi-steps. Large vesicles composed of BDAC and BPAS with embedded a cross-linking agent (divinylbenzene) underwent a radical polymerization. BPAS was extracted out using methanol (skeletonization). The headgroup of BDAC was cleaved off via hydrolysis in an acidic condition to yield vesicles where surfaces were covered with -COOH groups. There was no significant change in the overall shape. The skeletonized vesicles appear to have many holes with diameters up to about 25 nm. The holes retained even after hydrolysis. The hydrolyzed vesicles were not dispersed in water and most organic solvents such as tetrahydrofuran and chloroform, but dispersed in methanol.

• Polymer(Korea)
• /
• v.30 no.4
• /
• pp.286-292
• /
• 2006

Super water-absorbent resins were prepared by inverse suspension copolymerization of sodium acrylate, acrylamide and 2-hydroxyethyl acrylate using N, N'-methylene-bis-acrylamide as cross-linker. For the suspension copolymerization, monohexadecyl phosphate was employed as the dispersing agent, cyclohexane as the dispersing medium and potassium persulfate as the initiator. The dependence of water-absorption capacity on the amount of crosslinking agent, oil/water ratio, degree of neutralization and the composition of the copolymer were systematically investigated. Furthermore, the swelling kinetics of the super water-absorbent copolymer was carried out. The absorption of the resins is more than 1800 g/g for deionized water and 100 g/g for 0.9% NaCl solution, respectively. The copolymers showed an increased salt resistance and enhanced water retention of soil.

• Polymer(Korea)
• /
• v.37 no.3
• /
• pp.288-293
• /
• 2013

A group of molecularly imprinted polymers (MIPs) with specific recognition for chiral (S)-ibuprofen were successfully prepared based on hydrogen bonds, utilizing ${\alpha}$-methacrylic acid as a functional monomer. The IR analysis of MIPs showed that the blue- and red-shifted hydrogen bonds were formed between templates and functional monomers in the process of self-assembly imprinting and re-recognition, respectively. According to UV-Vis analysis, we found that the ratio of host-guest complexes between template molecule and functional monomer was 1:1. The effect of cross-linker's quantity on the polymerization was studied by transmission electron microscope (TEM). The adsorption selectivity experiments indicated that MIPs exhibited higher selectivity to (S)-ibuprofen than those to ketoprofen and (R)-ibuprofen, (S)-ibuprofen's structural analogs.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.3
• /
• pp.899-906
• /
• 2013

Using generated conformations from docking analysis by Gold algorithm, some 3D-QSAR models; CoMFA and CoMSIA have been created on 39 N-benzoylated phenoxazines and phenothiazines, including their S-oxidized analogues. These molecules inhibit the polymerization of tubulin into microtubules and thus they have been studied for the development of antitumor drugs. Training set for the CoMFA and CoMSIA models using 30 docked conformations gives $q^2$ Leave one out (LOO) values of 0.756 and 0.617, and $r^2$ ncv values of 0.988 and 0.956, respectively. The ability of prediction and robustness of the models were evaluated by test set, cross validation (leave-one-out and leave-ten-out), bootstrapping, and progressive scrambling approaches. The all-orientation search (AOS) was used to achieve the best orientation to minimize the effect of initial orientation of the structures. The docking results confirmed CoMFA and CoMSIA contour maps. The docking and 3D-QSAR studies were thoroughly interpreted and discussed and confirmed the experimental $pIC_{50}$ values.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.910-912
• /
• 2006

Barrier ribs in plasma display panels (PDPs) function to maintain the discharge space between the glass plates as well as to prevent optical cross-talking. The barrier ribs currently employed are typically $300{\mu}m$ pitch, $110{\sim}120{\mu}m$ in height, with upper and lower widths of $50{\mu}m$ and $80{\mu}m$, respectively. It has been reported that barrier ribs can be fabricated by screen-printing, sand blasting, etching and photolithographic processes. In this study, photosensitive barrier rib pastes were formulated and systematically evaluated in terms of photolithographic process variables such as printing, drying, UV exposure, development and sintering. It was found that the use of UV absorbent, polymerization inhibitor and surfactant were very effective in controlling the width uniformity of barrier ribs in the photolithographic method of barrier rib patterning.

• Animal cells and systems
• /
• v.2 no.4
• /
• pp.513-520
• /
• 1998

Though the wandering spiders do not produce webs for prey-catching, they have silk producing apparatus. Among the four kinds of silk glands in the wolf spider, Pardosa astrigera, the ampullate one is the most predominant gland in both sexes, and is composed of three functional parts; excretory duct, storage ampulla and convoluted tail regions. The duct is basically composed of three superposed types of layers which are inner cuticles, monolayered epithelial cells and peripheral connective cells. The electron lucent subcuticles which have the functions of water removal and orientation of silk fibers during polymerization are well developed at the anterior region near the spinneret. Whereas the endocuticles which contain two types of banding patterns at the cross section are developed at the rest of the duct region. The secretory silks are synthesized within the glandular epithelial cells of the tail as secretory granules, and then released to the inner cavity of the storage ampulla by the mechanism of apocrine secretion. Most of these secretory vesicles are originated from the rough endoplasmic reticula of the glandular epithelial cells, whereas no Golgi complexes are found in any of the cells which have been examined.

• Applied Chemistry for Engineering
• /
• v.3 no.2
• /
• pp.280-287
• /
• 1992

Aromatic liquid crystalline polyesters were synthesized from terephthalic acid(TPA), biphenyl dicarboxylic acid(BPA) and hydroquinone(HQ) by solution polymerization. Effects of TPA/BPA ratio(by mole %) on the thermal properties, thermal stability and textures of mesophases were investigated with DSC, TGA, cross-polarized microscopy and X-ray diffractometer. The synthesized polymers in this study were thermotropic and showed nematic textures. Melting temperature($T_m$) and isotropization temperature($T_i$) of polymer increased and thermal stabilities of polymer were improved with the content of BPA. Most of the polymers in this study had crystallinity more than 30%.

• Journal of the Korean Applied Science and Technology
• /
• v.27 no.4
• /
• pp.508-514
• /
• 2010

Regenerated cellulose fibers were prepared from three pulps containing different degree of polymerization(DP) and $\alpha$-cellulose contents by dry-jet wet spinning technique with cellulose dope in N-methylmorpholin N-oxide (NMMO). The effect of antioxidant, n-propyl gallate (PG) on the properties of different regenerated celluloses was studied using X-ray diffraction, copper number calculation, and viscometry. The degradaqtion of regenerated cellulose from pulp containing higher DP and lower $\alpha$-cellulose content was occurred more seriously. The tensile strength and initial modulus of regenerated cellulose fiber obtained from NMMO dope with PG were higher than those of fiber obtained from NMMO dope without PG. All fibers showed the round shape cross section and typical cellulose II crystalline structure.

• Journal of Adhesion and Interface
• /
• v.15 no.3
• /
• pp.109-115
• /
• 2014

In this study, we synthesized and identified microcapsule containing isocyanate, and investigated the mechanical and adhesion properties of polyurethane resin by adding microcapsule. We found out that the core material of microcapsule and the component weight fraction of microcapsule from the FT-IR and TGA analysis. From the results of adhesion and mechanical property tests, we confirmed that in case of using microcapsule for adhesive resin composition, adhesion strength, tensile strength and abrasion were improved by cross-linking reaction between urethane and IPDI in microcapsule.

• Journal of the Korean Chemical Society
• /
• v.53 no.3
• /
• pp.340-344
• /
• 2009

HEMA/vinyl-substituted polyphosphazene was prepared by the ring-opening polymerization of phosphonitrillic chroride trimer at $200{\sim}300\;{^{\circ}C}$, followed by Grignard reaction with vinyl magnesium bromide and then by the reaction with HEMA(2-hydroxyethyl methacrylate). HEMA/vinyl-substituted polyphosphazene was copolymerized with EGDMA(ethylene glycol dimethacrylate; used as a cross-linker for the free-radical copolymerization), NVP (N-vinyl-pyrrolidone) in the presence of AIBN (azobisisobutyronitrile) as a radical initiator. The oxygen transmissibility, water content and visible-ray transmissibility of the resulting copolymer were measured to be Dk/t 88, 30.89% and 87%, respectively, indicating that the copolymer can be used as a good contact lens material.