• Title/Summary/Keyword: 폴리이미드

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Synthesis of Soluble Copolyimides Using an Alicyclic Dianhydride and Their $CO_2/CH_4$ Separation Properties (지환족 다이안하이드라이드를 이용한 용해성 폴리이미드 공중합체 합성 및 메탄/이산화탄소 분리특성)

  • Park, Chae Young;Lee, Yongtaek;Kim, Jeong Hoon
    • Membrane Journal
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    • v.24 no.1
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    • pp.1-9
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    • 2014
  • In this study, four soluble homo- and co-polyimides using 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA) and 4,4'-diaminodiphenyl ether (ODA) monomers were synthesized to develop the gas separation membrane with good $CO_2/CH_4$ separation properties. To prepare the copolyimides, 20 mol% of three dianhydrides - (4,4'-(hexafluoroisoproplidene)diphthalic anhydride (6FDA), 4,4'-biphthalic anhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) - were added in DOCDA-ODA monomer mixture, respectively. All the synthesized homo- and co-polyimides were characterized by FT-IR. Their thermal properties were analyzed with differential scanning calorimeter (DSC). Dense membranes were prepared from these copolyimides to check their gas permeation properties for $CO_2$ and $CH_4$ gases using a time-lag method. The permeation testing results are as follows; DOCDA/ODA homopolymer showed 1.71 barrer of $CO_2$ permeability and 74.35 of $CO_2/CH_4$ selectivity. The three polyimide copolymers (DOCDA/6FDA-ODA, DOCDA/BPDA-ODA, DOCDA/BTDA-ODA) showed lower $CO_2/CH_4$ selectivities and higher $CO_2$ permeabilities than the homopolymer (DOCDA-ODA). DOCDA/6FDA-ODA showed twice times higher $CO_2$ permeabilities without severe $CO_2/CH_4$ selectivity loss than the DOCDA-ODA.

The Effect of Diamine and Solvent on The Synthesis of Polyimides and Their Film Properties (폴리이미드의 합성과 필름의 물성에 미치는 디아민과 용매의 효과)

  • Choi, Hyeong-Ki;Lee, Ho-Sik;Chung, Chang-Nam;Kim, Jum-Sik
    • Applied Chemistry for Engineering
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    • v.2 no.3
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    • pp.253-261
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    • 1991
  • Polyamic acids, precursor polymers of polyimides have been obtained by the solution polycondensation of benzophenone tetracarboxylic dianhydride (BTDA) with 4, 4'-diamino diphenyl methane (MDA) and/or 3, 3'-dimethyl benzidine (OTB). The reaction was carried in two solvent systems such as m-cresol and m-cresol/xylene mixture. The results of TGA analysis showed that the polyimide films had good thermal stability with the initial decomposition temperature ranging from $540^{\circ}$ to $590^{\circ}$. According to DSC analysis of polymers, the glass transition temperature was over $340^{\circ}$. Polyimide film samples, showed good mechanical and electrical properties, had over $16Kg/mm^2$ of tensile strength and about 200 KV/mm of dielectric breakdown voltage. The properties of the copolymer from MAD/OTB were better than those of the homopolymer from MDA. And the polymer synthesized in m-cresol had lower properties than that obtained in m-cresol/xylene.

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Electrical Properties and Preparation of 6FDA/4-4'DDE Polyimide Thin films by Bapor Deposition Polymerization method (진공증착중합법을 이용한 6FDA/4-4'DDE 폴리이미드 박막의 제조와 전기적 특성)

  • 이붕주;김형권;이덕출
    • Journal of the Korean Vacuum Society
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    • v.7 no.3
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    • pp.229-236
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    • 1998
  • In this paper, thin films of Polyimide (PI) were fabricated by vapor deposition polymerization method (VDPM) of dry processes. The film's properties with curing temperature and electrical properties were studies. The synthesis of hexafluoroisopropyliden-2,2-bis[phthalic anhydride](6FDA) and 4, 4'-diamino diphenyl ether (DDE) was carried out by vapor deposition polymerization(VDP) with the same deposition rate. The evaporation temperature of 6FDA and DDE were $214^{\circ}C$ and $137^{\circ}C$, respectively, so as to preserve balance of stoichiometry. The polymic acid (PAA) made by VDPM were changed to PI by thermal curing. The uniformity and density of PI thin films were increased according to increasing curing temperature. The relative permittivity and dissipation loss factor were 3.7 and 0.008 at the frequency of 100Hz~200KHz, respectively, for the fabricated in the curing temperature of $300^{\circ}C$. Also, the resistivity was about 1.05$\times$$ 10^{15}$$\Omega$cm at $30^{\circ}C$.

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The Change of Properties and Synthesis of Soluble Polyimides Based on 2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane (2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane을 이용한 용해성 폴리이미드의 합성과 특성변화)

  • Kim, Han-Sung;Ha, Soon-Hyo;Chun, Kyoung-Yong;Han, Hak-Soo;Joe, Yung-il
    • Applied Chemistry for Engineering
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    • v.10 no.7
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    • pp.979-984
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    • 1999
  • Aromatic soluble polyimides were synthesized from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and various dianhydrides such as pyromelltic dianhydride(PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride(BTDA), and 4,4'-(hexafluoroisopropylidene)-bis(phthalic anhydride)(6FDA). Polyimides prepared by thermal imidization were insoluble in common organic solvents (acetone, MNP, DMAc, DMSO, THF, and DMF) but those prepared by chemical imidization were soluble. The difference of solubility was explained by esterification between hydroxyl group and $CH_3COO^-$ from acetic anhydride used as a dehydration agent in chemical imidization. Glass transition temperatures of polyimides by thermal method were higher than those by chemical method. All of the polyimides are stable up to $300^{\circ}C$ regardless of the sample preparation. The x-ray diffraction patterns showed that all polyimides were amorphrous.

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Hydrolysis Stability of Sulfonated Phthalic and Naphthalenic Polyimide with Ester Bond (에스테르기를 도입한 술폰화 프탈계 폴리이미드와 나프탈렌계 폴리이미드의 수화안정성에 관한 연구)

  • 이영무;이창현;손준용;박호범
    • Membrane Journal
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    • v.13 no.2
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    • pp.110-117
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    • 2003
  • Sulfonated polyimides had been utilized and studied widely as available materials in chloro-alkali electrolysis, cationic exchange resins, and so on. However, a slow decrease in performance during experiments had been reported, which could be attributed to a loss of ionic conductivity related to either a continuous dehydration or polymer degradation. One of main reasons to account for the degradation of sulfonated polymers is the hydrolysis leading to polymer chain scission and decrement of molecular weight. Therefore, the objective of our study was to investigate possible imide cycle and additional ester bond cleavage connected with $SO_3$H presence under hydrated condition. In order to confirm and obtain as clear information as possible about breakages of bonds via $^1H\; and \;^{13}C$ NMR and IR spectroscopic analyses, our study was performed by model compound. Consequently, model compounds with both phthalic and naphthalenic imide ring and ester bonds were synthesized to evaluate the hydrolysis stability of sulfonated polyimide. The experiments were performed for prepared model compounds before and after aging in deionized water at $80^{\circ}C$ and were terminated by lyophilization technique. The aging products were finally analyzed by NMR and IR spectroscopy.

Preparation and Characterization of Polymer Coated BaTiO3 and Polyimide Nanocomposite Films (고분자로 표면 코팅된 BaTiO3와 이를 이용한 폴리이미드 나노복합필름의 제조 및 특성)

  • Han, Seung San;Han, Ji Yun;Choi, Kil-Yeong;Im, Seung Soon;Kim, Yong Seok
    • Applied Chemistry for Engineering
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    • v.17 no.5
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    • pp.527-531
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    • 2006
  • We have prepared organophilic inorganic particles and polyimide (PI) nanocomposite having excellent thermal stability and high dielectric constant that can be used for electronic application such as capacitor. We have chosen barium titanate (BT), a high dielectric constantmaterial and its surface was coated with nylon 6 to improve the affinity with PI. The FT-IR and TEM studies showed that the organophilic inorganic particle (BTN) has a polymer shell with thickness of 5 nm. We have suggested that it is possible to control the thickness of coating surface and also indicated the relationship between the ratio of inside and outside radius of BTN and the weight fraction of BT. The PI nanocomposite films based on poly(amic acid) and BTN were prepared by cyclodehydration reaction. The homogeneous dispersion of BTN in PI matrix was identified by using SEM. We have investigated the effect of BTN content on the coefficient of thermal stability, integral procedural decomposition temperature (IPDT), and dielectric constant of PI nanocomposite films.

Electrical Conductivity Behavior of 6FDA-based Fluorinated Polyimide/PMMA-g-MWCNT Nanocomposite Film (6FDA를 포함한 불소계 폴리이미드와 PMMA가 그래프트된 카본나노튜브 나노복합필름의 전기 전도성 연구)

  • Yun, Sung-Jin;Im, Hyun-Gu;Kim, Joo-Heon
    • Polymer(Korea)
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    • v.34 no.2
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    • pp.97-103
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    • 2010
  • PMMA was grafted on MWCNT surface in order to prepare conducting film composed of 6FDAbased polyimide/MWCNT. The electrical conductivity of 6FDA-based polyimide/PMMA-g-MWCNT was investigated as a function of PMMA-g-MWCNT content. Dispersion of MWCNT in 6FDA-based polyimide composite film was better than the pristine MWCNT due to the interaction force between PMMA and 6FDA-based polyimide. Electrical conductivity was interpreted by percolation threshold theory. As a result, 6FDA-6FpDA/PMMA-g-MWCNT which have high critical exponents and low critical concentration showed better dispersion than polyimide composite material that contains DABA(diamino benzoic acid).

The Preparation and the Gas Permeation Characteristics of the Soluble Polyimides (용해성 폴리이미드의 제조 및 기체투과특성)

  • Chun, Kyoung-Yong;Kim, Han-Sung;Han, Hak-Soo;Joe, Yung-il
    • Applied Chemistry for Engineering
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    • v.9 no.2
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    • pp.306-310
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    • 1998
  • The soluble polyimides(PMDA/diamine/dianhydride) were prepared and investigated. After coating the prepared PMDA/diamine/dianhydride solution into the commercial tubular alumina ceramic membranes, gas permeation characteristics was investigated. $T_g{\prime}s$ of the polyimides were in the range of $337{\sim}358^{\circ}C$ and thermal stability was good. The polymer was soluble in NMP, DMAc, DMSO, THF, and m-cresol. The adhesion between the alumina membrane and the soluble polyimide was excellent. The soluble polyimide/alumina membranes containing 6FDA showed the highest permeability among others. The permeability of nitrogen of PMDA/1,3PDA/6FDA-alumina membrane was about $7.6{\times}10^{-7}(mol/m^2{\cdot}Pa{\cdot}s)$ in the gas permeation experiments. The ideal separation factor of $O_2/N_2$ and $H_2/N_2$ in PMDA/1,3PDA/6FDA-alumina membrane were 6.19, and 70.0, respectively.

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Effect of Plasma Treatment on Permeability and Selectivity Characteristics of Mixture Gas through Polyimide Membrane (플라즈마 처리된 폴리이미드 막의 기체투과특성)

  • 배성렬;노상호;류대선;박희진
    • Membrane Journal
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    • v.11 no.1
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    • pp.38-49
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    • 2001
  • The surface of polyimide membrane was modified by plasma treatment using Ar and NH~. and the permeability and selectivity for the mixture gas $(CO_2/N_2=20/80 vol%)$ were measured. The per¬meation experiments were performed by a variable volume method at $30^{\circ}$C and total pressure of 5 atm, The effect of the plasma conditions such as treatment time, power input, gas flow rate and pressure in the reactor on the transport Dwperties of modified membranes was investigated. The surface of the plasma treated membrane was analyzed by means of FTlR - ATH, ESCA and AFM. The dependences of the wettability and the etching on plasma treatment time were investigated by use of the contact angle and the weight loss measurement. Measurements of gas pcnneability characteristic were performed using both dry and wet membranes. The effects of experimental conditions such as temperature on the membrane performance were studied.

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