• Title, Summary, Keyword: chlorotrifluoroethylene (CTFE)

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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.

Preparation and Characterization of Proton Conducting Crosslinked P(VDF-co-CTFE)-MAA/SEMA membranes (수소이온 전도성 가교된 P(VDF-co-CTFE)-MAA/SEMA 막 제조 및 분석)

  • Patel, Rajkumar;Lei, Zeng Xiao;Heo, Sung Yeon;Kim, Jong Hak
    • Membrane Journal
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    • v.23 no.4
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    • pp.290-296
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    • 2013
  • Poly(vinylidenefluoride-co-chlorotrifluoroethylene) P(VDF-co-CTFE) polymer was attached to methacrylic acid (MAA) in the presence of 1,8-diazabicyclo[5,4,0]undec-7-ene(DBU) catalyst to prepare P(VDF-co-CTFE)-MAA copolymer. The modified P(VDF-co-CTFE)-MAA was polymerized with 2-sulfoethyl methacrylate (SEMA) monomer in the presence of 4',4'-azobis(4-cyanovaleric acid(ACVA) initiator by free radical polymerization to form the proton conducting membrane. The ratio of the SEMA was increased in the membrane to increase the presence of the acidic group. The maximum IEC value that was observed at 50% SEMA was around 0.82 meq/g, which is consistent with the water uptake value. The highest proton conductivity achieved by P(VDF-co-CTFE)-MAA/SEMA membrane with 50% SEMA was approximately 0.041 S/cm. This indicates that the available ionic group for the proton conduction increases with the increase in the SEMA in the membrane.

Preparation and Characterization of Proton Conducting Composite Membranes From P(VDF-CTFE)-g-PSPMA Graft Copolymer and Heteropolyacid

  • Seo, Jin-Ah;Roh, Dong-Kyu;Koh, Jong-Kwan;Kim, Jong-Hak
    • Korean Membrane Journal
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    • v.10 no.1
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    • pp.20-25
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    • 2008
  • Proton conducting composite membranes were prepared by solution blending of poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(sulfopropyl methacrylate) (P(VDF-CTFE)-g-PSPMA) graft copolymer and heteropolyacid (HPA). The P(VDF-CTFE)-g-PSPMA graft copolymer was synthesized by atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of P(VDF-CTFE). FT-IR spectroscopy revealed that HPA nanoparticles were incorporated into the graft copolymer via hydrogen bonding interactions. The water uptake of membranes continuously decreased with increasing HP A concentration up to 45wt%, after which it slightly increased. It is presumably due to the decrease in number of water absorption sites due to hydrogen bonding interaction between the HP A particles and the polymer matrix. The proton conductivity of membranes increased with increasing HPA concentration up to 45wt%, resulting from both the intrinsic conductivity of HP A particles and the enhanced acidity of the sulfonic acid of the graft copolymer.

Preparation and Characterization of Graft Copolymer/$TiO_2$ Nanocomposite Polymer Electrolyte Membranes (가지형 공중합체/$TiO_2$ 나노복합 고분자 전해질막의 제조 및 분석)

  • Koh, Jong-Kwan;Roh, Dong-Kyu;Patel, Rajkumar;Shul, Yong-Gun;Kim, Jong-Hak
    • Membrane Journal
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    • v.20 no.1
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    • pp.1-7
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    • 2010
  • A graft copolymer, i.e. poly(vinylidene fluoride-co-chlorotrifluoroethylene )-g-poly(styrene sulfonic acid) (P(VDF-co-CTFE)-g-PSSA) with 47 wt% of PSSA was synthesized via atom transfer radical polymerization (ATRP). This copolymer was combined with titanium isopropoxide (TTIP) to produce graft copolymer/$TiO_2$ nanocomposite membranes via sol-gel process. $TiO_2$ precursor (TTIP) was selectively incorporated into the hydrophilic PSSA domains of the graft copolymer and grown to form $TiO_2$ nanoparticles, as confirmed by FT-IR and UV-visible spectroscopy. Water uptake and ion exchange capacity (IEC) decreased with TTIP contents due to the decrease in number of sulfonic acid in the membranes. At 5 wt% of TTIP, the mechanical properties of membranes increased while maintaining the proton conductivity.

Synthesis and Characterization of Proton Conducting Graft Copolymer Membranes (수소이온 전도성 가지형 공중합체 전해질막 제조 및 분석)

  • Roh, Dong Kyu;Koh, Jong Kwan;Seo, Jin Ah;Kim, Jong Hak
    • 한국신재생에너지학회:학술대회논문집
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    • pp.126.2-126.2
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    • 2010
  • The "grafting from" technology to prepare the well-defined microphase-separated structure of polymer using atom transfer radical polymerization (ATRP) will be introduced in this presentation. Various amphiphilic comb copolymers were synthesized through this approach using poly (vinylidene fluoride) (PVDF), poly (vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE) and poly(vinyl chloride) (PVC) as a macroinitiator. Hydrophilic side chains such as poly (styrene sulfonic acid) (PSSA) or poly (sulfopropyl methacrylate) (PSPMA) were grafted from the mains chains using direct initiation of the chlorine atoms. The structure of mass transport channels has been controlled and fixed by crosslinking the hydrophobic domains, which also provides the greater mechanical properties of membranes. Successful synthesis and microphase-separated structure of the polymer were confirmed by $^1H$ NMR, FT-IR spectroscopy and TEM. The grafted/crosslinked membranes exhibited good mechanical properties (400 MPa of Young's modulus) and high thermal stability (up to $300^{\circ}C$), as determined by a universal testing machine (UTM) and TGA, respectively.

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