• Macromolecular Research
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• v.14 no.3
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• pp.373-382
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• 2006

A series of crosslinkable, waterborne polyurethanes (I-WBPUs) were prepared by in-situ polymerization using isophorone diisocyanate (IPDI)/poly(tetramethylene oxide) glycol (PTMG, $M_n$=2,000)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA)/aminoplast[hexakis(methoxymethyl)melamine (HMMM)] as a crosslinking agent. Typical crosslinkable, waterborne polyurethanes (B-WBPUs) blended from WBPU dispersion and aqueous HMMM solution was also prepared to compare with the I-WBPUs. The crosslinking reaction between WBPU and HMMM was verified using FTIR and XPS analysis. The effect of the HMMM contents on the dynamic mechanical thermal, thermal, mechanical, and adhesion properties of the I-WBPU and B-WBPU films were investigated. The storage modulus(E'), glass transition temperatures of the soft segment ($T_{gs}$) and the amorphous regions of higher order ($T_{gh}$), melting temperature ($T_m$), integral procedural decomposition temperature (IPDT), residual weight, $T_{10%}$ and $T_{50%}$ (the temperature where 10 and 50% weight loss occurred), tensile strength, initial modulus, hardness, and adhesive strength of both I-WBPU and B-WBPU systems increased with increasing HMMM content. However, these properties of the I-WBPU system were higher than those of the B-WBPU system at the same HMMM content. These results confirmed the in-situ polymerization used in this study to be a more effective method to improve the properties of the WBPU materials compared to the simple blending process.

• Analytical Science and Technology
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• v.19 no.3
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• pp.218-225
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• 2006

A molecularly imprinted polymer (MIP) was synthesized by radiation-induced polymerization (RIP), where the ferulic acid was used as a template molecule, 4-vinylpyridine as a monomer and ethylene glycoldimethacrylate (EGDMA) as a cross-linking monomer. The MIP was packed in a glass column using a slurry method for use in medium pressure liquid chromatography (MPLC). The MPLC column was tested for separation and purification of ferulic acid from the rice oil. When repeated three times, the MPLC separation/purification yielded the ferulic acid with the purity higher than ~99%. The chemiluminescence of the luminal (5-amino-2,3-dihydro-1,4-phtalazinedione) measured on a potato disc slide (5.0 mm thick) was enhanced in the presence of ferulic acid, while, without the ferulic acid, the chemiluminescence of luminol on the potato slice disc was not observed, which suggests the ferulic acid obtained from the rice oil can be useful for immunoassay.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.297-298
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• 2007

• Textile Coloration and Finishing
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• v.9 no.5
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• pp.63-74
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• 1997

Polyurethane microcapsules were synthesized by interfacial polymerization in an aqueous poly(ethylene glycol) dispersion with ethylenediamine as chain extender of toluene diisocyanate in perfume oil using poly(vinyl alcohol) as the stabilizing agent. The effect of chemical structure on the average particle size and distributions, morphologies, and thermal properties to design microcapsules for the sustained release system was investigated. It came to be known that polyurethane microcapsules with ethylene diamine as chain extender had a rounder, more permeable and controlled release membranes. And the release test of polyurethane microcapsules with different soft segment content was done to certify the effect of long methylene chain. According to the higher molecular weight of polyether polyol, the release rate of microencapsulated disperse dye molecular was faster.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3083-3087
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• 2013

Diacetylene lipid monomers possess the capability to self-assemble into vesicles via polymerization under ultraviolet irradiation, resulting in the formation of polydiacetylene (PDA) liposomes. Exposure of the polymerized vesicles to external stimuli is known to induce a unique blue-to-red color transition. The cyclic oligosaccharide ${\alpha}$-cyclodextrin known for its use in many applications, such as drug delivery, purification, and stimulus sensing, is able to form an inclusion complex with poly(ethylene glycol) (PEG) in aqueous solution. In this study, we prepared polymeric liposomes with PEG (PEG-PDA) with the aim of improving the stability of the vesicles and colorimetric response toward ${\alpha}$-cyclodextrin. We demonstrated that PEG-PDA liposome displays unique characteristics compared with native PDA liposome and it also shows apparent chromic properties of the inclusion complex formation with ${\alpha}$-cyclodextrin.

• Archives of Pharmacal Research
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• v.18 no.1
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• pp.18-21
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• 1995

Poly(ethylene glycol)(PEG) macrocers teminated with acrylate groups and semi-interpenetrating polymer networks (IPNs) composed of poly-.epsilon.-capolactone(PCL) and PEG macromer were syntheswized with the aim of obtaining a bioerodible hydrogel that could be used to release drugs for implantable delivery system. Polymerization of PEG macromer resulted in the formation of cross-linked gels due to the multifunctionality of macromer. Non-crosslinked PCL chains were interpenetrated into the cross-linked three-dimensions networks of PEG. The IPNs, largw drug loading lower concentration of PEG macromer in the IPNs concentration and the higher molecular weight of PEG macromer. Also, 5-FU was more fast released than hydrocortisone to the increased water solubility.

• Archives of Pharmacal Research
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• v.19 no.1
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• pp.18-22
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• 1996

Acrylate-terminated poly (ethylene glycol) (PEG) macromer was prepared by the reaction of PEG with acryloyl chloride. Photopolymerization of PEG macromer resulted in the formation of cross-linked PEG network. Interpenetrating polymer networks (IPNs) based on PEG and poly(acrylic acid) (PAA) was obtained via template polymerization of AA to the PEG network by UV curing. The swelling degree of the IPNs hydrogel increased with an increase of pH value due to the association-dissociation between carboxylic acid of PAA and either of PEG through hydrogen bounding. The swelling-deswelling behavior proceeded reversibly for the IPNs upon changing pH. Release of indomethacin from the IPNs demonstrated "on-off" regulation with pH fluctuation.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.327-330
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• 1996

Poly(L-leucine)(PLL)/poly(ethylene oxide)(PEO)/poly (L-leucine)(PLL) block copolymers were synthsized by polymerization of L-leucine N-carboxyanhydride with diamine-terminated PEO for possibility of wound dressing which may have several advantages such as 1) increase of solubility, 2) control of biodegradation, 3) absorption of body fluid. 4) non-immunogenic effect than PLL homopolymer wound dressing aleady commercialized. Water content increased with an increase of PEO content in the block copolymer due to the hydrophilicity of PEO. Release of silver sulfadiazine(AgSD) from AgSD loaded wound dressing increased with an increase of PEO content in the block copolymer. It was found that the number of Pseudomonas aeruginosa decrease with an increase of PEO content due to the fast release of antibacterial agents with an increase of PEO content in the block copolymer.

• Applied Chemistry
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• v.15 no.2
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• pp.85-88
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• 2011

We synthesized ethylene-styrene copolymer by coordination polymerization using 2 types of pyrazolato metallocene catalysts ((1,2,4-Me₃C₅H₄)TiCl₂(3,5-iPr₂C₃HN₂), (tert-BuC₅H₄) TiCl₂(3,5-iPr₂C₃HN₂)). We observed the effects of styrene concentration on the catalytic activity, yield, molecular weight and molecular weight distribution.

• Macromolecular Research
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• v.10 no.2
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• pp.85-90
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• 2002

Poly (ethylene oxide)/polylatide/poly(ethylene oxide) (PEO/PL/PEO) tri-block copolymers, which each block is connected by ester bond, were synthesized by coupling reaction of PL with PEO in the presence of pyridine. PL/PEO/PL tri-block copolymer was synthesized by ring opening polymerization of L-lactide initiated by PEO in the presence of stannous octoate. Degradation behavior of the copolymers was investigated in a pH 7.4 phosphate buffer saline (PBS) at 37$\pm$1 $^{\circ}C$. Gel permeation chromatography (GPC) and $^1$H-nuclear magnetic resonance (NMR) were used to monitor the change of mass loss, molecular weight and composition of copolymers. In hydrolytic degradation, the PEO/PL/PEO tri-block copolymer with high PEO contents affected the increase of its mass loss, and resulted in the decrease of its molecular weight as well as PEO composition. However, when PL/PEO/PL and PEO/PL/PEO tri-block copolymers had similar PEO contents, PEO/PL/PEO decreased faster in molecular weight and PEO composition than PL/PEO/PL.