• Title, Summary, Keyword: vinylidene fluoride (VDF)

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Dehydrofluorination of Vinylidene Fluoride- Trifluoroethylene Copolymer by Phase Transfer Catalysis (Vinylidene Fluoride-Trifluoroethylene 공중합체의 상전이촉매작용에 의한 탈불화수소화)

  • Jo, Jae-Hwan;Song, Ha-Yul;Guk, Yun-Hwan
    • Textile Science and Engineering
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    • v.32 no.1
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    • pp.57-63
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    • 1995
  • Films of vinylidene fluoride - trifluoroethylene (VDF-TrFE ) copolymer were dehydrofluorinated in aqueous sodium hydroxide solutions by phase transfer catalysis(PTC). Conjugated C=C double bonds in the polymer back-bone were bonds in the dehydrofluorination of VDF-TrFE copolymer. The color of film became brown and finally black with rigid double bonds during the PTC reaction. It was found from UV/VIS spectroscopic measurements that the length of conjugated double bonds of dehydrofluorinated VDF-TrFE copolymer was longer than that of dehydrofluorinated poly(vinylidene fluoride) . It was ascribed to the reaction activity due to the difference of solubility parameter between the sample and reaction solution. Thermal behavior by DSC analysis showed that the dehydrofluorination occurred at least in the crystal surfaces as well as in the amorphous chains.

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Curie Temperature Transition According to Microstructure of Polymer Chain in Poly(VDF/TrFE/CTFE) Terpolymer (Poly(VDF/TrFE/CTFE) 3성분계 고분자의 배열구조에 따른 상전이 온도의 변화)

  • Kim, Eun-Kyoung;Lee, Sang-Goo;Ha, Jong-Wook;Park, In-Jun;Lee, Soo-Bok;Park, Cheol-Min;Kim, Young-Ho
    • Polymer(Korea)
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    • v.31 no.4
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    • pp.343-348
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    • 2007
  • In this study, terpolymer of vinylidene fluoride (VDF), trifluoroethylene (TrFE), and chlorotrifluoroethylene (CTFE) were prepared by suspension polymerization using di-tertiary-butyl peroxide (DTBP) as an initiator. The structural characteristics including microstructure and chain conformation of the polymers have been carefully elucidated as a function of the chemical composition using NMR, FT-IR. The intensity of absorption bands of the $\beta$-phase gradually decreases and the $\gamma$-phase increases with the increment of CTFE mol%. The analysis results of DSC shows that the Curie phase transition temperature ($T_c$) of the terpolymer gradually shifts to ambient temperature and trace becomes smaller and broader with the increment of CTFE mol%. Also, activation energies of the samples were calculated by Freeman-Carroll method.

Effect of External Electric Field on the Isothermal Crystallization of Poly(ethylene Oxide) (외부 전장이 Poly(ethylene Oxide)의 등온결정화에 미치는 영향)

  • 김영호;최재원;김갑진
    • Proceedings of the Korean Fiber Society Conference
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    • pp.271-274
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    • 2001
  • 최근 압전성 및 유전성, 비선형 광학전도성 등과 같은 특성을 갖는 전기전자 및 광기능성 고분자에 대한 연구가 많이 이루어지고 있다[1-2]. 그 중에서 압전 및 초전성을 나타내는 대표적 유기 고분자인 poly(vinylidene fluoride)(PVDF)의 경우 압전성을 향상시키기 위하여 vinylidene. fluoride(VDF)나 vinyl fluoride(VF), trifluoroethylene(TrFE) 등과 공중합시킨 고분자들에 대한 연구가 활발히 진행되어 왔다[3-4]. (중략)

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Basic Study on P(VDF-TrFE) Smart Sensor for Monitoring Composite Structure Behaviors (복합재료구조물 거동 관찰을 위한 P(VDF-TrFE) 스마트센서의 기초연구)

  • Bae, Ji-Hun;Chang, Seung-Hwan
    • Composites Research
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    • v.28 no.3
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    • pp.75-80
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    • 2015
  • Poly(vinylidene fluoride-trifluoroethylene; P(VDF-TrFE)) is one of the most promising electroactive polymers with numerous application potentials in many fields of industry. Because of its good electro-mechanical properties P(VDF-TrFE) has been used for a number of sensors and actuators and also can be used for monitoring composite structure behaviors as a sensor. Three different ways (Electrical poling, annealing-cooling, and pressing) to enhance ${\beta}$-phase of P(VDF-TrFE) film were carried out. A microscopic analysis was conducted using X-ray diffraction to investigate the effect of such treatments on piezoelectric properties of P(VDF-TrFE) film. From the results, poling, annealing-cooling, and pressing were all effective to enhance ${\beta}$ crystallinity of P(VDF-TrFE) film and the maximum increase rate was 62.80% from 45.29% of the control group.

Synthesis of Poly(vinylidene fluoride-co-hexafluoropropylene) (비닐리덴 플루오라이드와 헥사플루오르프로필렌 공중합체의 합성)

  • Lee, Sang Goo;Ha, Jong-Wook;Park, In Jun;Lee, Soo-Bok;Lee, Jong Dae
    • Polymer(Korea)
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    • v.37 no.1
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    • pp.74-79
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    • 2013
  • Polyvinylidene fluoride (PVDF) and its copolymer with hexafluoropropylene (HFP) were successfully prepared from free radical solution polymerizations using diisopropyl peroxidicarbonate (DIPPDC) in the presence of 1,1,2-trichlorotrifluoroethane (R-113). The reactivity ratios of VDF and HFP were estimated as$r_{VDF}=2.06{\pm}0.03$ and $r_{HFP}{\approx}0$. This result indicates that HFP cannot undergo self propagation. The weight-average molecular weight and molecular weight distribution of copolymers were found to decrease with increasing HFP content. The melting temperature of copolymers linearly decreased with the increase of HFP content because of the introduction of HFP. Moreover, no melting peak was observed for the copolymers with high HFP content. The glass transition temperature of copolymers gradually increased with the increase of HFP content due to the restricted flexibility of the polymer chains.

Experimental Evidence for the Existence of a New Transition of a VDF and TrFE Copolymer (P(VDF/TrFE)의 새로운 전이에 대한 실험적 증거)

  • 김갑진;이종순;조항원
    • Proceedings of the Korean Fiber Society Conference
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    • pp.105-109
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    • 2002
  • vinylidene fluoride(VDF)와 trifluoroethylene(TrFE)의 공중합체 인 P(VDF/TrFE)는 전기활성을 갖는 강유전성 결정이므로 압전성 및 초전성 재료로 PVDF와 더불어 널리 사용되고 있다. 그러나 P(VDF/TrFE)는 어떤 온도 이상에서는 all-trans conformation을 하는 강유전 결정상이 전기적으로 불활성으로 되면서 PVDP의 $\alpha$-결정의 사슬배좌(trans-gauche)와 유사한 상유전 결정상으로 전이하는 상승 Curie 전이 온도 (T$^{\uparrow}$ $_{c}$ )가 존재하기 때문에 P(VDF/TrFF)의 압전재료로서의 적용온도 범위가 넓지 못하다는 단점이 있다. (중략)

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Miscibility and Phase Separation Behavior of P(VDF-co-HFP) and Poly(vinyl methyl ketone) Blends (P(VDF-co-HFP)와 poly(vinyl methyl ketone) 블렌드물의 혼화성 및 상분리 거동)

  • 김영호;홍성돈;김갑진
    • Proceedings of the Korean Fiber Society Conference
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    • pp.319-320
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    • 2003
  • 압전성과 초전성을 나타내는 고분자인 poly(vinylidene fluoride)(PVDF)는 poly(methyl methacrylate), poly(vinyl acetate), 및 Poly(vinyl methyl ketone)(PVMK) 등과 블렌딩하면 혼화성(miscibility)이 있다. 이들 블렌드물들을 용융온도 이상으로 승온시키면 낮은 온도에서는 균일상으로 존재하지만, 온도가 계속 증가하면 상분리되어 LCST(lower critical solution temperature)를 나타낸다[1]. 이러한 승온에 의한 상분리 거동에서 외부전장을 가하면 전기활성 고분자인 PVDF에 영향을 주어 상분리 거동이 변화될 것으로 예산된다. (중략)

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Measurements of the Second Harmonic Coefficients of the Ferroelectric Polymer P(VDP-TrFE)(72/28 mole%) at 1064 and 532 nm Wavelength (강유전성 고분자 P(VDF-TrFE)(72/28 mole%)의 파장 1064 및 532 nm에 대한 2차 비선형 광학 계수 측정)

  • 정창수;임종선;박광서;김도석;이범구
    • Proceedings of the Optical Society of Korea Conference
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    • pp.232-233
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    • 2001
  • 2차 비선형광학 물질이 높은 응용성을 갖기 위해서는 큰 2차 비선형광학 계수뿐만 아니라 넓은 파장 영역에 걸친 투명성을 가지고 있어야 한다. vinylidene fluoride(VDF)와 trifluoroethylene(TrFE)가 공중합된 f(VDf-TrFE) 공중합체는 이러한 조건을 갖추고 있는 강유전성 물질이다. 우리는 몰비율이 72:28인 P(VDF-TrFE)을 ITO기판위에 casting하고 corona 극화한 뒤, 두 개의 입력 파장(1064nm, 532nm)에 대한 2차 조화파 발생 실험을 실시하고 Herman과 Hayden의 마커무의 식을 이용하여 2차 비선형 광학 계수를 측정하였다. (중략)

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Phase separation Behavior of P(VDF-co-HFP)/PBA and P (VDF-co-HFP)/P(BA-co-BS) Blends (P(VDF-co-HFP)/PBA 및 P(VDF-co-HFP)/P(BA-co-Bs) 블렌드의 상분리 거동)

  • 홍성돈;김영호;김갑진
    • Proceedings of the Korean Fiber Society Conference
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    • pp.193-194
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    • 2003
  • 전기활성 고분자인 poly(vinylidene fluoride)(PVDF)를 전기 비활성 고분자와 블렌드시키는 경우 어떤 블렌드계에서는 용융 온도 이상에서 LCST(lower critical solution temperature) 상분리 거동을 나타내는데[1,2], 이때 외부 전장을 가해주면 이들의 상분리 거동에 영향을 미칠 수 있다[3]. PVDF와 블렌딩시켰을 때 LCST 상분리 거동을 나타내는 고분자로는 poly(methyl methacrylate), poly(ethyl methacrylate), poly(1,4-butylene adipate) (PBA) 등이 있다[l,3]. (중략)

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Electrical Properties of Metal-Ferroelectric-Semiconductor Structures Based on Ferroelectric P(VDF-TrFE) Copolymer Film

  • Lee, Gwang-Geun;Park, Hyeong-Jin;Han, Hui-Seong;Park, Byung-Eun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.85-86
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    • 2007
  • A poly(vinylidene fluoride-trifluoroethyene) (P(VDF-TrFE)) copolymer thin film having ${\beta}$ phase was prepared by sol-gel method. The electrical properties of the film were studied to evaluate the possibility for appling to a ferroelectric random access memory. In order to characterize its electrical properties, we produced a MFS (metal-ferroelectric-semiconductor) structure by evaporation of Au electrodes. The C-V (capacitance-voltage) measurement revealed that the Au/P(VDF-TrFE)/Si structure with a 4 wt% film had a memory window width of about 0.5V for a bias voltage sweep of 1V.

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