• Journal of Chest Surgery
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• v.42 no.3
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• pp.375-379
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• 2009

Difficulty in exposing anastomotic sites is a frequently encountered problem during surgical repair of a distal aortic arch aneurysm via median sternotomy or lateral thoracotomy. Endovascular repair has th limitation that it usually requires surgical rerouting of some of the brachiocephalic branches in order to get sufficient length for proximal fixation of the stent-graft. To take advantage of each approach, we fixed the distal end of the prosthetic graft by means of a pre-mounted metallic stent instead of performing conventional surgical anastomosis during the repair of distal arch aneurysms with using median sternotomy and hypothermic circulatory arrest. We report here on our experience with such 3 patients.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.643-649
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• 2017

Biodegradable enzymes such as lipase and proteinase can hydrolyze not only fatty acid esters and triglycerides, but also aliphatic polyesters. We measured the biodegradability that biodegradable enzymes have an important role in the degradation of natural aliphatic poly material such as PLA, corn starch, and polyethylene glycol in the natural environment. However, we investigated on the biodegradability of PLA, PLA and Polyethylene acrylate blended, and PLAcoPolyethylene polymerized with PLA graft copolymer Polyethylene glycol acrylate. When prepared biodegradable polymers. the Mechanical properties of them were measured on Biodegradability, thermal properties, real time in-situ electrical monitoring of polymers resin. Therefore BOD and biodegradation of PLAcoPolyethylene was graft copolymerized with PLA and polyethylene acrylate were measured at a lower rate than the other samples.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.990-997
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• 1994

The vulcanized NR and blend films were prepared with mixing of natural rubber latex (NRL) and methyl methacrylated grafted latex(MGL) with various additives by dipping process. It was investigated the basic properties of vulcanized NR films that is optimum condition of the mature time, swelling degree, cure time at $110^{\circ}C$, and measured the mechanical properties of tensile strength and elongation of its condition. In order to identify the surface structure and the slip properties of blend films contact angles and static and kinetic friction coefficient were measured. Contact angles were decreased with increment of blend ratio of MGL, and static and kinetic friction coefficient were decreased rapidly for the NR/MG and NR-d-MG films than for the NR films. From the results, NR/MG and NR-d-MG films has slip's reinforcement in skin contact surface with increased of blend ratio of MGL.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.546-549
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• 2010

A 70-year-old man was transferred to our center due to severe epigastric and back pain with the impression of a ruptured thoracic aortic aneurysm. Six months previously, he had undergone insertion of stent graft into the descending thoracic aorta at another hospital. The findings of the computed tomographic scan suggested a rapidly growing malignant mediastinal tumor rather than a ruptured aneurysm. Exploratory thoracotomy confirmed the diagnosis and the tumor was resected along with the portion of the aorta contained in it. This exemplary case should raise the concern against overzealous application of endovascular aortic repair.

• Polymer(Korea)
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• v.26 no.2
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• pp.153-159
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• 2002

In order to remove $NO_3;^-$ ion from ground-water, fibrous ion -exchangers, APP-g-GMA, were synthesized by GMA grafting onto PP trunk polymer with E-beam accelerator for pre-irradiation. Their degrees of grafting and amination yield increased up to $60^{\circ}C$ and showed maximum values as 133%, 88%, respectively. And their swelling ratio and ion exchange capacity at the maximum values are 86%, 2.5 meq/g, respectively which was higher than commercial ion-exchangers such as IMAC HP555 and Amberlite IRA 400. Optimum adsorption condition of $NO_3;^-$ ion was measured at pH 5~6 and -Cl form of APP-g-GMA containing trimethylammonium group showed the highest adsorption capacity.

• Polymer(Korea)
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• v.25 no.1
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• pp.49-55
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• 2001

The bi-functional ion exchangers, SAPP-g-(AN/St) were synthesized with mixed vinyl monomers(acrylonitrile and styrene) onto PP fabric by the pre-irradiation grafting with E-beam and its subsequent amidoximination and sulfonation. The degree of grafting of PP-g-(AN/St) was increased with decreasing acrylonitrile composition in the mixed monomers. The water uptake of copolymers increased with decreasing in the amidoxime ratio in the copolymers and increased by sulfonation, but decreased by amidoximation. The $UO_2^{2+}$ adsorption capacity of SPP-g-St, APP-g-AN, and SAPP-g-(AN/St) were 12.4, 34.0, and 38.0 mg/g, respectively and the optimum adsorption time is about 50 hrs. As a result of uranium adsorption, the synthesized ion exchanger, which we obtained have also good affinity toward the adsorption or chelating with $UO_2^{2+}$ ions.

• Elastomers and Composites
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• v.36 no.3
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• pp.177-187
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• 2001

Polypropylene(PP)/polyurethane(PU) blends with reactive compatibilizers were prepared by the compositional quenching process. Maleic anhydride grafted PP(MPP) and hydroxyethyl maleimide grafted PP(HPP) were introduced as reactive compatibilizers. The formation of HPP and the reactions of compatibilizers with the PU components were confirmed by FT-IR spectroscopy. The morphology, tensile properties, thermal stability, and surface property were studied. The blends prepared by the compositional quenching showed better dispersed domain morphology than the melt blends. The PU domain size became more uniform and reduced in size with increasing the amount of compatibilizers. The blends with HPP showed sightly smaller domain sire than the blends with MPP. The blends with compatibilizers all showed improved tensile properties, surface property. and thermal stability due to the interfacial adhesion effect. The blends with MPP showed higher surface energy than the blends with HPP, but the latter showed better thermal stability compared to the former.

• Elastomers and Composites
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• v.44 no.3
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• pp.209-221
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• 2009

Polyolefins are important commodity polymers with the largest volume of business owing to their outstanding combination of cost performance and excellent physical properties. However, the lack of functional groups often has limited their end uses, such as compatibilizer, modifier and adhesive, where the interaction with other materials is especially important. The incorporation of functional groups as polymer segments to afford block or graft polyolefin copolymers has been extensively investigated in the context of the functional polyolefin hybrids. Living polymerization processes have been considered to be an efficient method to prepare the polyolefin hybrids with precisely controlled architecture and compositions. Among the living polymerization techniques, controlled/"living" radical polymerization (CRP) methods are very effective not only because of the controllability of polymerization but also because of the versatility of monomers and polymerization conditions. In this review paper, progresses on the preparations of polyolefin graft or block copolymers through CRP techniques are summarized. The commodity polymers such as polyisobutylene, polyethylene and polypropylene are combined with polar segments such as polyacrylate, polymethacrylate, polystyrene to yield functionalized polyolefins.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.59-66
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• 2003

The comb-type grafted polymer hydrogels, which composed of N-isopropylacrylamide monomer and oligo(N-isopropylacrylamide-co-tert-butylacrylamide) [oligo(NIPAAm-co-t-BAM)], were synthesized by redox polymerization in 5~10% methanol aqueous solution using ammonium peroxodisulfate (APS) at 4 oC for 24h. The lower critical solution temperatures (LCSTs) of the comb-type grafted hydrogels were decreased with increase of t-BAM content in the grafted copolymer. We observed the effect of crosslinker and concentration of oligo(NIPAAm-co-t-BAM) on the shrinking/swelling ratio of hydrogels. Changes of shrinking/swelling ratio were decreased with increase of concentration of crosslinker. The increase of grafted oligo(NIPAAm-co-t-BAM) in the hydrogel shows an fast changes of shrinking/ swelling rate. The comb-type grafted hydrogels are expected to be valuable for the sensing materials of time-temperature labels(TTLs).

• Journal of Adhesion and Interface
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• v.12 no.2
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• pp.62-66
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• 2011

In this study, we synthesized a excellent adhesive chlorinated polyolefin (CPO)-g-$\beta$-carboxy ethyl acid ($\beta$-CEA) by radical polymerization. Also, we prepared low-level toxic primer for polypropylene (PP) using CPO-g-$\beta$-CEA and studied toxic and adhesion property. We identified the graft structure and properties of the prepared chlorinated polyolefin-g-$\beta$ CEA using FT-IR, DSC, UTM. Graft ratio were optimum value at 5 wt% $\beta$-CEA contents in CPO-g-$\beta$ CEA. And the primer for PP was prepared with CPO-g-$\beta$ CEA and adhesive builder PX-95 content. Finally, optimum peel strength obtained when PX-95 contents was 3 wt%.