• 폴리머
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• 제24권5호
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• pp.664-672
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• 2000

Poly(ethylene naphthalate)/poly($\varepsilon$-caprolactone) (PEN/PCL)의 용융 블렌딩시 필연적으로 발현되는 상호에스테르 교환반응은 PEN/PCL 공중합체를 형성하게 된다. 블렌드의 조성비, 상호에스테르 교환반응 조건 그리고 사용된 촉매가 형성된 공중합체의 randomness와 평균 sequence length에 미치는 영향을 살펴보고 이들과 블렌드의 생분해 특성과의 관계를 확인하여 보았다. 용융 블렌딩에 의하여 얻어진 PEN/PCL 공중합체는 randomness가 0과 1사이인 것으로 보아 블럭 공중합체임을 알 수 있었으며, 열처리 시간과 온도의 증가 그리고 촉매의 첨가에 의하여 randomness가 1에 근접하고 PEN과 PCL의 평균 sequence length 모두 감소하는 것으로 보아 랜덤 공중합체로 변화됨을 확인할 수 있었다. 이러한 공중합체의 생성과 랜덤화는 PEN/PCL 블렌드의 생분해성 감소를 초래함을 알 수 있었다.

• 폴리머
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• 제25권5호
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• pp.699-706
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• 2001

연신온도, 연신속도, 연신비 등 연신 조건에 따른 poly(ethylene 2,6-naphthalate) (PEN)의 배향상태 변화를 살펴보았다. 연신온도가 낮을수록 연신속도가 빠를수록 연신비에 따라 큰 복굴절 값을 보이며 FT-IR ATR dichroism 방법으로 구한 배향 특성도 복굴절의 실험결과를 뒷받침하였다. PEN을 $120^{\circ}C$에서 연신하면 무정형사슬 배향함수 ($f_a$)가 연신속도가 빠를수록 높은 값을 갖지만 $141^{\circ}C$에서 연신하면 반대로 연신속도가 빠를수록 낮은 값을 갖게 된다. 이러한 경향은 결정화 속도와 사슬 이완속도와의 관계로부터 설명이 가능하다. X-선 회절 실험 결과로부터 PEN의 naphthalene ring 구조가 필름표면에 평행하게 배열됨을 확인할 수 있었다.

• Fibers and Polymers
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• 제4권4호
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• pp.156-160
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• 2003

Poly(ethylene 2,6-naphthalate) (PEN)/Poly(ethylene glycol) (PEG) copolymers were synthesized by two step reaction during the melt copolymerization process. The first step was the esterification reaction of dimethyl-2,6-naphthalenedicarbox-ylate (2,6-NDC) and ethylene glycol (EG). The second step was the condensation polymerization of bishydroxyethylnaphthalate (BHEN) and PEG. The copolymers contained 10 mol% of PEG units with different molecular weights. Structures and thermal properties of the copolymers were studied by using $^1{H-NMR}$, DSC, TGA, etc. Especially, while the intrinsic viscosities of PEN/PEG copolymers increased with increasing molecular weights of PEG, but the glass transition temperature, the cold crystallization temperature, and the weight loss temperature of the copolymers decreased with increasing molecular weights of PEG. Consequently, the hydrophilicities by means of contact angle measurement and moisture content of the copolymer films were found to be significantly improved with increasing molecular weights of PEG.

• 한국응용과학기술학회지
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• 제24권2호
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• pp.167-173
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• 2007

The surface of poly(ethylene naphthalate) film applicable to high temerature insulator for convection microwave oven was modified with silicone coating solutions in the presence of silane crosslinking agent. The structure and properties of the PEN films were investigated by using Fourier transform IR spectroscopy, viscometry, microscopy, and tensile tests. The experimental results showed that the coating with silicone enhanced thermal stability up to $200^{\circ}C$, and slightly lowered the tensile strength and elongation of the PEN films. Judging from dimensional stability results the silicone coated PEN films can not be used for higher temperature insulator above $230^{\circ}C$. Serious dimensional contraction of films was obtained during heat treatment at $250^{\circ}C$ even for 1h. However, the surface of those films still have same chemical structure of silicones. Therefore, If we use PEN film prestretched at $230^{\circ}C$ as base one it will be possible to prepare a high temperature insulator up to $230^{\circ}C$. Conclusively, a silicone coated PEN film can be suitable for the application to convection microwave oven door insulator at high temperature up to $230^{\circ}C$.

• 폴리머
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• 제35권2호
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• pp.146-151
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• 2011

폴리(에틸렌 나프탈레이트) 중합 시 2,6-dimethyl naphthalene dicarboxylate와 함께 사용되는 디올 화합물인 ethylene glycol(EG), 1,3-propanediol(PD) 그리고 1,4-butanediol(BD)의 사용에 따른 공중합체의 물성을 살펴보았다. EG와 함께 PD 혹은 BD를 40% 이내 첨가하는 경우 합성된 폴리에스터가 무정형을 유지함을 알 수 있으며 이는 열적 특성과 배향 특성, 그리고 기계적 특성을 저하시키는 반면 치수안정성을 증가시킴을 획인할 수 있어 합성 폴리에스터가 유연기판 소재로의 적용 가능성을 확인하였다.

• Macromolecular Research
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• 제10권1호
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• pp.44-48
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• 2002

The supermolecular structures of poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalate) (PEN), and their blend were investigated with optical microscopy and small angle light scattering. With increasing the crystallization temperature, incomplete spherulitic texture was developed for the PET samples. At a high crystallization temperature of 220 $^{\circ}C$, the light scattering pattern represented a random collection of uncorrelated lamellae. The general morphological appearances for the PEN samples were similar to that of the PET. A notable feature was that the spherulites of the PEN formed at 200 $^{\circ}C$ showed regular concentric bands arising from a regular twist in the radiating lamellae. The spherulitic morphology of the PET/PEN blend was largely influenced by the changes of the sequence distribution in polymer chains determined by the level of transesterifcation. The increased sequential irregularity in the polymer chains via transesterification caused a morphological transition from a regular folded crystallite to a tilted lamellar crystallite.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.70-73
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• 2003

최근 들어 poly(trimethylene terephtha)ate)(PTT)를 폴리에스터계 고분자들인 PET, PTN, PBN 등과 블렌드하고 이들의 특성 변화에 대해 검토한 결과가 많이 발표되고 있다. PTT를 PET나 PTN과 블렌드시키면 혼화성이 없으나, 이들 블렌드물을 용융시키면 점차 하나의 T$_{g}$를 나타내어 혼화성을 갖는다[1-3]. 반면에 PTT와 PBN을 블렌드시키면 처음부터 혼화성이 존재한다[4]. 이같이 PTT와 혼합되는 고분자의 종류에 따라 혼화성이 달라지는데, 본 연구는 PTT와 poly(ethylene naphthalate)(PEN)을 블렌드시키면 혼화성이 어떻게 되는가를 검토한 것이다. (중략)

• 폴리머
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• 제24권1호
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• pp.113-123
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• 2000

Poly(p-hydroxybenzoate) (PHB)/poly(ethylene terephthalate) (PET) 8/2공중합 폴리에스테르계 액정고분자와 poly(ethylene 2,6-naphthalate) (PEN) 및 poly(ethylene terephthalate)를 용융혼합하여 삼상계 블렌드물의 액정상 형성여부 및 기계적 성질을 조사하였다. PHB의 함량이 40 mo1%에서 급격한 점도의 감소로 토크의 값이 감소하였고, 인장강도와 초기 탄성율은 PHB의 함량이 증가함에 따라 액정고분자의 피브릴 형성으로 증가하였다. 섬유의 인장강도와 탄성율은 PHB의 함량과 권취속도를 증가시킴에 따라 증가하였고, 에스테르 교환반응은 용융혼합 시간에 따라 증가하였다. 에스테르 교환반응은 용융흔합물의 흔화성을 향상시키고, 동일 조성비의 단량체를 함유한 공중합체에서 나타나는 액정상을 형성하였다. PHB의 함량이 30 wt%에서는 부분적인 액정상이 나타나며, 40 wt%에서 삼상계 블렌드의 의사액정상이 나타났다.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.38-43
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• 1997

Poly(ethylene 2, 6-naphthalate-co-tetramethylene 2, 6-naphthalate) (PEN/PBN) copolymers were synthesized and studied by 13C NMR spectroscopy, DSC analysis and X-ray diffraction. A minimum in the melting point vs. composition curve was found at approximately 60 mol% tetramethylene 2, 6-naphthalate. The PEN/PBN copolymers were shown to be statistically random throughout the range of 1, 4-butanediol compositions. The melting point depression behavior of annealed PEN/PBN copolymers depended upon the sequence propagation probability, PS, which is suggested by indivisual crystal formation of two pure comonomers; that is, ethylene-naphthalate-ethylene, EE, and tetramethylene-naphthalate-tetramethylene, BB. However, it can be seen from the X-ray curve that the peaks of PEN/PBN copolymers appear from a crystal lattice which is governed only by the rich component between two different aliphatic units in the copolymer composition.

• Macromolecular Research
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• 제14권2호
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• pp.146-154
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• 2006

Organic and inorganic hybrid nanocomposites based on poly(ethylene 2,6-naphthalate) (PEN) and silica nanoparticles were prepared by a melt blending process. In particular, polymer nanocomposites consisting mostly of cheap conventional polyesters with very small quantities of inorganic nanoparticles are of great interest from an industrial perspective. The crystallization behavior of PEN/silica hybrid nanocomposites depended significantly on silica content and crystallization temperature. The activation energy of crystallization for PEN/silica hybrid nanocomposites was decreased by incorporating a small quantity of silica nanoparticles. Double melting behavior was observed in PEN/silica hybrid nanocomposites, and the equilibrium melting temperature decreased with increasing silica content. The fold surface free energy of PEN/silica hybrid nanocomposites decreased with increasing silica content. The work of chain folding (q) for PEN was estimated as $7.28{\times}10^{-20}J$ per molecular chain fold, while the q values for the PEN/silica 0.9 hybrid nanocomposite was $3.71{\times}10^{-20}J$, implying that the incorporation of silica nanoparticles lowers the work required to fold the polymer chains.