• Korean Chemical Engineering Research
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• 제49권3호
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• pp.271-276
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• 2011

대면적 대기압 플라즈마 반응 장비를 플라즈마-용액 시스템에 적용하여 액상 내부에 잠입된 폴리프로필렌(PP) 필름의 표면손상 없이 관능기 도입 가능성을 탐색하였다. 액상으로 1-butyl-3-methylimidazolium tetrafluoroborate: $[BMIM]^{+}[BF_{4}]^{-}$ 이온성 액체 수용액을 사용한 경우, 안정적으로 플라즈마를 발생시킬 수 있었다. PP 필름의 플라즈마 처리 결과, PP 표면에 다양한 산소 함유 관능기들이 도입되었음을 확인할 수 있었다. 플라즈마 처리 후 PP의 표면 자유에너지는 처리시간, 전압의 증가에 따라서 증가하며, 1.5M 이온성 액체 수용액 농도에서 가장 큰 값을 나타내었다. ATR-FTIR 분석 결과, 다양한 카르보닐 기(1,726 $cm^{-1}$, 1,643 $cm^{-1}$)와 하이드록시 기$(3,100{\sim}3,500\;cm^{-1})$의 흡광도가 증가하였고, XPS 분석은 ATR-FTIR 분석 결과를 뒷받침하여 주었다.

• 전기화학회지
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• 제11권4호
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• pp.304-308
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• 2008

Noble Poly (lithium 2-acrylamido-2-methyl propane sulfonate) and its copolymer with N-vinyl formamide based on trihexyl (tetradecyl) phosphonium acetate [$(C_6H_{13})_3$ P ($C_{14}H_{29}$) $CH_3COO$; $P_{66614}$ $CH_3COO$] and trihexyl (tetradecyl)phosphonium bis(trifluoromethane sulfonyl) amide ([$(C_6H_{13})_3P(C_{14}H_{29})$] [TFSA];$P_{66614}TFSA$) were prepared and analyzed to determine their characteristics and properties. The ionic conductivity of a copolymer based $P_{66614}TFSA$ ionic liquid system exhibits a higher conductivity ($8.9{\times}10^{-5}Scm^{-1}$) than that of a copolymer based $P_{66614}CH_3COO$ system ($1.57{\times}10^{-5}Scm^{-1})$. The charge on the TFSA anion is spread very diffusely through the S-N-S core and particularly in the trifluoromethane groups, and this diffusion results in a decreased interaction between the cation and the anion. The viscosity of $P_{66614}TFSA$ (39 cP at 343 K) and $P_{66614}CH_3COO$ (124 cP at 343 K), which is very hydrophobic, was fairly high. High viscosity leads to a slow rate of diffusion of redox species. The ionic conductivity of copolymer of a phosphonium ionic liquid system also exhibits higher conductivity than that of a homopolymer system. Phosphonium ionic liquids were thermally stable at temperatures up to $400^{\circ}C$.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.79-82
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• 2003

An ionomer is defined as an ion-containing polymer with a small amount (usually up to 10-15 mol%) of ionic groups along the backbone chains or as pendant groups. Ionomers have been extensively studied because of the significant changes in their physical properties due to the formation of ionic aggregates, such as enhanced mechanical properties, high melt viscosity, and increased thermal properties.$\^$1-5/ Although there have been many studies of ionomers, the crystallization behaviour of degradable ionomers is still not understood. (omitted)

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1054-1059
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• 1998

Fluorescence and dynamic light scattering measurements were applied to the study of formation and structure of aggregated colloidal particles in modified poly(ethylene-co-methylacrylate) ionomers in aqueous solution. Both 8-anillino-l-naphthalene-sulfonic acid (ANS) and pyrene were used as fluorescence probe to obtain the information on the structure of particle surface and inside, respectively. Three different ionomers used in this study started to aggregate at very dilute concentration, 3-8 x 10-6 g/mL. In this study, we demonstrate that the polyethylene ionomers can form stable nanoparticles. The hydrophobic core made of the polyethylene backbone chains is stabilized by the ionic groups on the particle surface. Such a formed stable nanoparticles have a relatively narrow size distribution with an average radius in the range of 27-48 nm, depending on the kind of ionic groups. Once the stable particles are formed, the particle size distributions were nearly constant. This study shows another way to prepare surfactant-free polyethylene nanoparticles.

• 전기화학회지
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• 제6권2호
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• pp.141-144
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• 2003

Proton conducting polymeric gels as the electrolytes of electrochemical capacitors have been prepared by two different methods: 1) swelling a polymethacrylate-based polymer matrix in aqueous solutions of inorganic and organic acids, and 2) polymerizing complexes of anhydrous acids and prepolymers with organic plasticizer. The FT-IR spectra strongly suggest that the carbonyl groups in the polymer matrix interact with protons from the doped acids. High ionic (proton) conductivity in the range of $6\times10^{-4}-4\times10^{-2}\;S\;cm^{-1}$ was obtained at room temperature for the aqueous gels. The non-aqueous polymer complexes showed rather low ionic conductivity, but it was about $10^{-3}\;S\;cm^{-1}\;at\;70^{\circ}C$ for the $H_3PO_4$ doped polymer electrolyte. The mechanisms of ion (proton) conduction in the polymeric systems are discussed.

• Macromolecular Research
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• 제9권6호
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• pp.332-338
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• 2001

Waterborne polyurethane as a new polymer electrolyte was synthesized by using relatively hydrophilic polyols. The morphology of polyurethane was changed as it was dispersed in water. In contrast to polyurethane ionomer, waterborne polyurethane did not form an ionic cluster but produced a binary system composed of hydrophilic and hydrophobic groups. In the colloidal system, the former and the latter existed at outward and inward, respectively. Waterborne polyurethane was prepared from poly(ethylene glycol) (PEG) /poly(propylene glycol) (PPG) copolymer, 4,4'-diphenylmethane diisocyanate(MDI), ethylene diamine as a chain extender, and three ionization agents, 1,3-propane sultone, sodium hydride and lithium hydroxide. PEG/PPG copolymer was used for suppressing the crystallinity of PEG and N-H bond was ionized for increasing the electrochemical stability of polyurethane. Low molecular weight poly(ethylene glycol) and poly(ethylene glycol dimethyl ether) (PEGDME) were used as plasticizers. DSC, FT-IR and $^1$H-NMR of the waterborne polyurethane were measured. Also, the ionic conductivity of solid polymer electrolytes based on waterborne polyurethane and various concentrations of low molecular weight poly(ethylene glycol) or PEGDME were measured by AC impedance.

• Bulletin of the Korean Chemical Society
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• 제7권5호
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• pp.399-402
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• 1986

The critical micelle concentration (CMC) of sodium deoxycholate (NaDC) and the effects of amides on the micellization processes have been studied by fluorometric technique using pyrene as a probe. The addition of amides as cosolvent destabilized the NaDC micelle and increased the CMC. The order of effectiveness for the perturbation of NaDC micelle was N-methylacetamide ${\ge}$ DMF > acetamide > formamide, which is the order of hydrophobicity of the amines. This indicated that the effect of amides on the micellization processes of NaDC arises from diminution of the hydrophobic effect. The electrostatic repulsion between ionic head groups in the NaDC micelle appeared to be much less than that in aliphatic ionic micelle. This was also revealed in the weaker dependence of the CMC on ionic strength. The premicellar association of NaDC was not significantly involved in the micellization processes of the bile salt.

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.177-184
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• 2019

An electrochemical detection method for capsaicin has been developed using ionic liquid (IL) doped graphene-titania-Nafion composite-modified electrode. The combination of IL (1-hexyl-3-methylimidazolium with hexafluorophosphate counter ion) in the composite-modified electrode resulted in a significantly increased electrochemical response for capsaicin compared to that obtained at the corresponding electrode without IL. The increased electrochemical signal could be ascribed to the decreased electron transfer resistance through the composite film and also to the effective accumulation of capsaicin on the electrode surface due to ${\pi}-{\pi}$ interaction of the imidazole groups of IL with the aromatic rings of capsaicin. The present IL composite-modified electrode can detect capsaicin with a concentration range from $3.0{\times}10^{-8}M$ to $1.0{\times}10^{-5}M$ with a detection limit of $3.17{\times}10^{-9}M$ (S/N = 3). The present sensor showed good reproducibility (RSD = 3.2%).

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.368-376
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• 1988

Transition metal PSSA ionomers containing Co(II), Ni(II), Cr(III), Ru(III), and Rh(III) are investigated by IR, Far-IR, UV-Vis and DSC. Reliable IR Spectroscopic criteria are established for assessing the degree of ion-exchange of PSSA ionomers and the local structures around metal cations in them. In the hydrated transition metal PSSA ionomers, the ionic groups are solvated by water molecules and there is no significant interactions between sulfonate group and metal cations. The visible spectra indicated that metal cations are present as [M$(H_2O)_6$]$^{n+}$ with Oh symmetry. Their $T_g$ values increase as the extent of ionic site concentration increases, but there is no direct dependence of $T_g$ on the nature of metal cations or their oxidation states. Thus, the water content in PSSA ionomer is found to have dominant influence on $T_g$ of hydrated transition metal PSSA ionomers. Dehydration of the hydrated transition metal PSSA ionomers results in direct interaction between ionic groups and significant color changes of the ionomers due to the changes of the local structures around metal cations. On the base of spectral data, their local structures are discussed. In case of dehydrated 12.8 and 15.8 mol % transition metal PSSA ionomers, no glass transition is observed in 25-$250^{\circ}C$ region and this is believed to arise from the formation of highly crosslinked structures caused by direct coordination of sulfonate groups of metal cations. In the 6.9 mol % transition metal PSSA ionomers, the glass transition is always observed whether they are hydrated or dehydrated and this is though to be caused by the sufficient segmental mobility of the polymer backbone.

• Journal of the Korean Wood Science and Technology
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• 제40권3호
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• pp.194-203
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• 2012

바이오매스 전처리에 효과적인 이온성 액체로 주목받고 있는 1-ethyl-3- methylimidazolium acetate를 사용하여 리기다소나무(pitch pine)로부터 리그닌을 추출하였고, 추출한 리그닌(Ionic Liquid Lignin : ILL)의 화학구조적 특성을 동일한 수종에서 단리한 milled wood lignin (MWL)과 비교분석하였다. 작용기 분석 결과 ILL과 MWL은 각각 10.0, 7.2%의 페놀성 수산기와 4.9, 11.0%의 메톡실기를 갖는 것으로 나타났다. ILL의 중량평균 분자량(3,995 Da)은 MWL (8,438 Da)에 비해 약 2배 정도 낮았으며, 다분산지수는 1.36으로 MWL (3.18)보다 낮은 값을 보였다. ILL의 열중량 분석 결과에 의하면 최대중량감소율(Vm)이 나타나는 온도(Tm)는 $306.6^{\circ}C$로 MWL ($341.9^{\circ}C$)보다 낮아 ILL이 MWL에 비해 열적으로 불안정하다는 것을 확인할 수 있었다.