• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.295-295
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• 2008

Water tree experiments were done for several types of cross-linked polyethylenes. Test method is followed by ASTM D6097. Polyethylene is divided for four subgroup. First One is chemically cross-linked general XLPE, and second one is chemically cross-linked tree-retardant XLPE, and the third one is silane cross-linked polyethylene made by monosil process, and the last one is silane cross-linked polythylene made by copolymer. Tree retardant XLPE shows the shortest water tree length. Cahemcally cross-linked general XLPE shows the longest water tree length. Silane cross-linked polyethylene by copolymer is similar to tree retardant XLPE and similar breakdown strength. So silane cross-linked XLPE by copolymer could be used for the the medium voltage cable which should have tree retardant characteristics.

• 한국의류산업학회지
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• 제8권5호
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• pp.577-584
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• 2006

The binding of heavy metal ions onto cross-linked chitosan in dilute aqueous solution has been investigated as a function of pH (4.0 and 7.0), agitation period (10-180min) and concentration of various metal cations (5, 10, 50 and 100ppm). In order to obtain adsorbents that are insoluble and stable, and prevent the dissolution loss of chitosan into an acidic aqueous solution, chitosan flakes were cross-linked with epichlorohydrine (ECH) and its adsorption behavior was compared with that of the non cross-linked chitosan. An advantage of ECH is that it does not eliminate the cationic amine functional group of chitosan. In terms of adsorption ratio, the chitosan cross-linked at an ECH was inferior to original chitosan and was found that chitosan has a selectivity much remarkable than the cross-linked chitosan in low concentrated metal solutions. However, no significant decreases in the adsorption ratios were observed between the cross-linked ECH-chitosan and the non cross-linked chitosan concerning the adsorption of $Ni^{2+}$, $Co^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ acidic solution.

• 분석과학
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• 제27권1호
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• pp.27-33
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• 2014

This study described about preparation of the cross-linked silk fibroin (SF) film by ${\gamma}$-irradiation of the casted SF film, which is fabricated from aqueous solution regenerated via fibers of cocoons and their application as supports for human cell culture. The properties of cross-linked SF film were evaluated by FT-IR spectroscopy, contact angle, solubility to water, thermal analysis, surface area analyzer, and morphology via scanning electron microscopy (SEM). The cross-linked SF films were not dissolved in water and exhibited the rough surface morphology, large surface area, and good thermal properties. The human fibroblast cell (CCD-986sk) and embryo kidney-ft cell were well growed on the surface of cross-linked SF film supports prepared by ${\gamma}$-irradiation. The cross-linked SF film prepared by ${\gamma}$-irradiation can be used as biomaterials for human cell culture.

• Macromolecular Research
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• 제17권11호
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• pp.926-930
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• 2009

A new method for encapsulating nanomaterials within intermediary layer cross-linked (ILCL) polymeric micelles using a bifunctional photo-cross-linking agent was developed. For ILCL polymeric micelles, an amphiphilic triblock copolymer of poly(ethylene glycol)-b-poly(2-hydroxyethyl methacrylate)-b-poly(methyl methacrylate) (PEG-PHEMA-PMMA) was synthesized via consecutive atom transfer radical polymerization (ATRP), Di(4-hydroxyl benzophenone) dodecanedioate (BPD) was used as a bifunctional photo-cross-linking agent. The PMMA-tethered Au nanoparticles and BPD, or pyrene and BPD were encapsulated in the PEG-PHEMA-PMMA micelles, and their intermediary layers were photo-cross-linked by UV irradiation for 1 h. The HEMA units donated labile hydrogens to the excited-state benzophenone groups in BPD, and they were subsequently cross-linked by BPD through radical-radical combination. The spherical structures of the PEG-PHEMA-PMMA micelles containing the Au nanoparticles or pyrene were unaffected by the photo-cross-linking process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.516-519
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• 1999

XLPE (Cross-Linked Polyethylene) which has good electric and physical characteristic is ideal material for Insulating material with force high volumetric resistance arid high dielectric constant. We study abort electric characteristics of XLPE by DCP and TMPTA content ration. DCP (Dicumylperoxide), which was used cross-linked agent contest, was changed from 1.0 to 0.5phr. TMPTA (Trimethyl-olpropane), which was used co cross-linked agent content, was changed from 0.5 to 1.5phr. Thermal analysis by DSC in order to observe tendency of Tg according to DCP and TMPTA content. Specimen 3 that content DCP 2.0phr and TMPTA 0.5phr has the highest value Breakdown strength cf specimen 3 (DCP 2.Ophr, TMPTA 1.0phr) is the highest, value and it increased in specific inductive capacity. This due to difference from cross-linked state by DCP and TMPTA content ratio.

• Archives of Pharmacal Research
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• 제29권12호
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• pp.1179-1186
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• 2006

Cross-linked starch microspheres were prepared using different kinds of cross-linking agents. The influence of several parameters on morphology, size, swelling ratio and drug release rate from these microspheres were evaluated. These parameters included cross-linker type, concentration and the duration of cross-linking reaction. Microspheres cross-linked with glutaraldehyde had smooth surface compared with those prepared with epichlorhydrine or formaldehyde. The particle size increased with increasing the cross-linking time and increasing the drug loading. Swelling ratio of the particles was a function of cross-linker type but not the concentration or time of cross-linking. Drug release from starch microspheres was measured in phosphate buffer and also in phosphate buffer containing a-amylase. Results showed that microspheres cross-linked with epichlorhydrine released all their drug content in the first 30 minutes. However, cross-linking of the starch microspheres with glutaraldehyde or formaldehyde decreased drug release rate. SEM and drug release studies showed that cross-linked starch microspheres were susceptible to the enzymatic degradation under the influence of alpha-amylase. Changing the enzyme concentration from 5000 to 10,000 IU/L, increased drug release rate but higher concentration of enzyme (20,000 IU/L) caused no more acceleration.

• Fibers and Polymers
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• 제7권4호
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• pp.328-332
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• 2006

Poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers cross-linked with pentaerythritol, a four-way cross-linker, are prepared to compare their mechanical and shape memory properties with the one cross-linked by glycerol. Composition of PEG and pentaerythritol is varied to search for the one with the best mechanical and shape memory properties. The highest shape recovery rate is observed for the copolymer composed of 30 mol% PEG-200 and 2.5 mol% pentaerythritol. Four-way cross-linking by pentaerythritol significantly improves shape recovery rate and retention of high shape recovery rate after repeated use compared to the one cross-linked by glycerol, a three-way cross-linker, and difference and advantage of additional cross-linking point are discussed.

• 한국재료학회지
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• 제16권5호
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• pp.302-307
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• 2006

The formation and processing of organic insulators on the device performance have been studied in the fabrication of organic thin film transistors (OTFTs). The series of polyvinyls, poly-4-vinyl phenol(PVP) and polyvinyltoluene (PVT), were used as solutes and propylene glycol monomethyl ether acetate(PGMEA) as a solvent in the formation of organic insulators. The cross-linking of organic insulators was also attempted by adding the thermosetting material, poly (melamine-co-formaldehyde) as a hardener in the compound. The electrical characteristics measured in the metal-insulator-metal (MIM) structures showed that insulating properties of PVP layers were generally superior to those of PVT layers. Among the layers of PVP series: PVP(10 wt%) copolymer, 5 wt% cross-linked PVP(10 wt%), PVP(20 wt%) copolymer, 5 wt% cross-linked PVP(20 wt%) and 10 wt% cross-linked PVP(20 wt%), the 10 wt% cross-linked PVP(20 wt%) layer showed the lowest leakage current characteristics. Finally, inverted staggered OTFTs using the PVP(20 wt%) copolymer, 5 wt% cross-linked PVP(20 wt%) and 10 wt% cross-linked PVP(20 wt%) as gate insulators were fabricated on the polyether sulphone (PES) substrates. In our experiments, we could obtain the maximum field effect mobility of 0.31 $cm^2/Vs$ in the device from 5 wt% cross-linked PVP(20 wt%) and the highest on/off current ratio of $1.92{\times}10^5$ in the device from 10 wt% cross-linked PVP(20 wt%).

• 한국식품과학회지
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• 제34권3호
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• pp.431-436
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• 2002

보통 옥수수 전분을 이용하여 저항전분을 제조할 때 저항 전분의 수율을 높일 수 있는 방법을 개발하기 위한 목적으로 가교결합 전분을 제조하고 annealing처리를 병행하였다. Annealing은 $40{\sim}60^{\circ}C$ 범위에서 실시하였고, 이와 비교하기 위하여 $70^{\circ}C$와 $100^{\circ}C$에서 열처리한 후 가교결합 전분을 제조하였다. RS 분석방법으로는 pancreain-gravimetric법(P/G법)을 사용하였다. 보통 옥수수전분과 고아밀로오스 옥수수전분으로 annealing하지 않고 가교결합 전분을 제조했을 때의 RS수율은 각각 14.7, 45.3%였고, annealing 한 후 가교결합 전분을 제조했을 때 28.0, 63.4%까지 증가하였다. 가교결합 전분의 팽윤력은 annealing 처리에 의해 영향받지 않았으나, 보통 옥수수전분으로 제조한 시료의 경우는 호화온도이상에서 열처리했을 때 팽윤력이 2배이상 증가하였다. 두가지 전분으로부터 제조된 가교결합 전분의 X-선 회절도와 주사전자현미경에 의한 특성 역시 annealing에 의해 영향받지 않았다.

• Applied Biological Chemistry
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• 제49권1호
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• pp.49-54
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• 2006

쌀 전분에 phosphorus oxychloride$(POCl_3)$를 단계별(전분 고형분 대비 $0.005{\sim}0.06%$)로 2시간 반응시켜 가교화 쌀 전분을 제조하고, 변성된 쌀 전분의 용해도, 팽윤력, RVA, DSC, X-ray 특성을 연구하였다. 팽윤력은 일반 쌀 전분 보다 다소 낮은 온도에서 증가되기 시작하였으나 그 이후는 모두 낮은 수치를 보여 가교화 쌀 전분이 일반 쌀 전분보다 완만한 상승을 나타내었다. 용해도는 가교화 쌀 전분이 일반 쌀 전분보다 전체적으로 낮은 결과를 나타내었고 $POCl_3$ 함량에 따른 유의적인 차이는 보이지 않았다. RVA 분석결과 가교화 쌀 전분이 일반 쌀전분보다 pasting temperature와 최고점도는 낮아졌고 holding strength와 final viscosity는 높은 경향을 나타내어 breakdown과 setback 은 낮은 것으로 나타났다. DSC 분석 결과 가교화 쌀 전분이 일반 쌀 전분보다 $T_o$, $T_p$, $T_c$가 감소하였으나 ${\Delta}H$의 경우 큰 차이가 나타나지 않았다. X-ray 회절분석 결과 일반 쌀 전분 보다 $POCl_3$ 함량에 따라 상대적 결정화도가 소폭 감소되는 결과를 나타내었으나 95% 신뢰도 수준에서 유의적인 차이는 없는 것으로 나타났다. 따라서 가교화 쌀 전분의 경우 전분입자가 $POCl_3$ 의해 강한 공유 결합을 형성함으로써 내열성, 내전단성의 성질이 생겨 호화가 일어난 후에 점도가 많이 낮아지지 않은 것으로 판단되며 전분의 결정형태에는 크게 영향을 미치지 않으나 전분의 무정형 부분에 영향을 주어 쌀 전분의 팽윤력, 용해도 및 pasting property등의 물리화학적 성질에 변화를 주는 것으로 판단되었다.