• Title/Summary/Keyword: pyromellitic dianhydride

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A Study on the Properties of Epoxy Based Powder Coating with Various Curing Agents (에폭시 분체도료의 경화제 종류에 따른 물성에 관한 연구)

  • Park, Jae-Hong;Shin, Young-Jo
    • Applied Chemistry for Engineering
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    • v.9 no.1
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    • pp.58-65
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    • 1998
  • Substituted dicyandiamide(Sub-DICY), Accelerated dicyandiamide(Acc-DICY), Trimellitic anhydride(TMA), Pyromellitic dianhydride(PMDA) and Phenolic curing agent(Ph.C.A.) are mainly used for epoxy powder coating curing agent. Various characteristics of epoxy films fully cured by optimum condition such as mechanical properties like $T_g$, tensile strength, elongation at break hardness, abrasion resistance and chemical properties like water absorption, acid resistance, alkali resistance and electrical properties, corrosion resistance are determined by various measuring devices and analyses devices. In conclusion, phenolic curing agent was shown excellent thoughness but severe color change as temperature increased. Acid anhydride has excellent insulation properties and color stability at elevated temperature but lower thoughness and adhesion to substrate. DICY curing agent was shown high water absorption and severe color chance as temperature increased.

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The Electric Breakdown Chatacteristics of Polyimide Thin Films by Self Healing Method (자기절연회복법에 의한 폴리아미드 박막의 절연파괴특성)

  • Kim, Hyeong-Gweon;Lee Eun-Hak;Park, Jong-Kwan
    • Journal of the Korean Institute of Telematics and Electronics T
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    • v.36T no.2
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    • pp.1-7
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    • 1999
  • The polymide thin films were fabricated by vapor deposition polymerized method of dry processes and studied the electric breakdown characteristics by self healing method. Polyamic-acid(PAA) thin films prepared by vapor deposition-polymerization (VDP) from PMDA(Pyromellitic dianhydride) and DDE(4,4'-diaminodiphenyl ether) were changed to PI thin films by thermal curing. In the same sample, electric breakdown fields increase with increasing test number, and then saturated over test number of the 25th. When the curing temperatures were 200$^{\circ}C$, 250$^{\circ}C$, 300$^{\circ}C$ and 350$^{\circ}C$, the electric breakdown strengths of PI were 1.21MV/cm, 3.94MV/cm, 4.61MV/cm and 4.55MV/cm at the test number of 40th.

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Optically Active and Organosoluble Poly(amide-imide)s Derived from N,N'-(Pyromellitoyl)bis-L-histidine and Various Diamines: Synthesis and Characterization

  • Faghihi, Khalil;Shabanian, Meisam;Hajibeygi, Mohsen
    • Macromolecular Research
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    • v.17 no.11
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    • pp.912-918
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    • 2009
  • An optically active diacid containing the L-histidine moiety was prepared by reacting pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydride) 1 with L-histidine 2 in acetic acid, and was polymerized with several aromatic diamines 5a-g to obtain a new series of optically active poly(amide-imide)s (PAIs) using two different methods, such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,N-dimethylformamide (DMF) system as a condensation agent. The resulting new polymers 6a-g with inherent viscosity was obtained in good yield. The polymers were readily soluble in polar organic solvents, such as N,N-dimethyacetamide (DMAc), N,N-dimethyformamide (DMF), and dimethyl sulfoxide (DMSO). The obtained polymers were characterized by FTIR, specific rotation, elemental analysis as well as $^1$H-NMR spectroscopy and gel permeation chromatography (GPC). The thermal stability of the resulting PAIs was evaluated with thermogravimetric analysis techniques under a nitrogen atmosphere.

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • v.17 no.12
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

A study on the electric breakdown of polyimide thin film fabricated by vapor deposition polymerization (진공증착중합법에 의해 제조된 폴리이미드박막의 절연파괴특성)

  • 이붕주;김형권;김종석;한상옥;박강식;김영봉;이덕출
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.293-296
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    • 1997
  • The experimental system used for vapor deposition polymerization (VDP) from PMDA (Pyromellitic dianhydride) and DDE (4, 4-diaminodiphenyl ether) were changed to PI (polyimide) thin films by thermal curing. The curing temperatures were 20$0^{\circ}C$, 25$0^{\circ}C$, 30$0^{\circ}C$, 35$0^{\circ}C$. When test number was 40, the electric breakdown strengths of PI were 1.21MV/cm, 3.94MV/cm, 4.61MV/cm, 4.55MV/cm according to curing temperatures.

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Synthesis of Poly Imide/α'ω'-di Poly Acrylamide (3-Mercaptopropyl) Trimethoxysilane Terminated Copolymer (양 말단에 MPTMS-아크릴아미드로 치환된 폴리이미드의 합성)

  • Min, Jun Ho;Park, Chan Young;Min, Seong Kee
    • Korean Journal of Materials Research
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    • v.26 no.9
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    • pp.478-485
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    • 2016
  • An amide group was introduced to restrain the cohesion of silica nano-particles and copolymerized with polyamic acid. Amide block copolymers were prepared using silica and (3-mercaptopropyl) trimethoxysilane (MPTMS) with a siloxane group, using 2, 6-Lutidine as a catalyst. Amide block polymers and copolymers were synthesized via ATRP after brominating pyromellitic dianhydride (PMDA) and polyamic acid of methylene diphenyl diamine (MDA) using ${\alpha}$-bromo isobutyryl bromide. Characteristic peaks of copolymer with amide and imide groups and patterns of amorphous polymers were studied using FT-IR and XRD analyses; an analysis of the surface characteristic groups was conducted via XPS. Changes in the thermal properties were examined through DSC and TGA; solubility for solvents was also studied.

PROPERTIES OF THE CRYSTALLINE POLYIMIDE FILM DEPOSITED BY IONIZED CLUSTER BEAM

  • Whang, Chung-Nam
    • Proceedings of the Materials Research Society of Korea Conference
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    • 1992.05a
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    • pp.6-6
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    • 1992
  • Ionized cluster beam deposition (ICBD) technique has been employed to fabricate high-purity crystalline polyimide (PI) film. The pyromellitic dianhydride (PMDA) and oxydianiline (ODA) were deposited using dual ICB sources, Fourier trans forminfraredspectroscopy (FT-IR), X-ray photoemission spectroscopy (XPS), and Transmission electron microscopy (TEM)study show that the bulk and surface chemical properties and the crystalline structure are very sensitive to the ICBD conditions such as cluster ion acceleration voltage and ionization voltage, At optimum ICBD conditions, the PI films have a maximum imidization, negligible impurities(∼1% isoimide), and a good crystalline structure probably due to the high surface migration energy and surface cleaning effect. These characteristics are superior to those of films deposited by other techniques such as colvent cast, vapowr deposition, or sputtering techniques.

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Preparation of Novel Iron Phthalocyanine Containing Reactive Groups and its Deodorizing Property on Cellulose

  • Kim, Eun-Mi;Choi, Jae-Hong
    • Textile Coloration and Finishing
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    • v.25 no.4
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    • pp.247-253
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    • 2013
  • The enzyme-like catalytic functions of metal complex phthalocyanine derivatives those containing carboxylic acid groups could be applied as odor-removing systems and antibacterial systems. Pyromellitic dianhydride and 4-nitrophthalimide were used as starting material for synthesizing dinitro-tetracarboxylic acid iron phthalocyanine(compound 1). Then diamino-tetracarboxylic phthalocyanine(compound 2) was obtained by reduction of compound 1. For the formation of covalent bond with cellulose fiber, cyanuric chloride was introduced to the amino group of compound 2 by condensation reaction compound 3. The exhaustion method was employed for adsorbing compound 3 on cotton fiber. K/S values of each fabrics were measured by a CCM system and deodorizing rates were tested by a detector tube method for ammonia gas. K/S values of treated cotton fiber with compound 3 were arranged from 2.1 to 4.2 at $90^{\circ}C$ of exhaustion temperature. Deodorizing rates provided result of 81%, 84%, 88%, 91%, by passing time of 30 min, 60 min, 90 min, 120 min, respectively.

Phosgen-free Synthesis of Oligoureas Having Amino End-groups: Their Application to the Synthesis of Poly(urea-imide)

  • Chang, Ji-Young;Kim, Beom-Jin
    • Fibers and Polymers
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    • v.3 no.2
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    • pp.55-59
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    • 2002
  • The thermal reaction of acetoacetanilide in the presence of aniline or phenol yielded carbanilide in quantitative yields. This reaction was applied to the synthesis of polyurea. Bisacetoacetamides were prepared from diamines and diketene in DMF. They were thermally polymerized in the presence of phenol or a diamine (6FDA) to yield polyureas of low molecular weights. The polymers were soluble in DMSO and NMP. $^1{H-NMR}$ analysis showed that they had amino group terminated structures. Poly(urea-imide) was synthesized by the reaction of an oligourea diamine with pyromellitic dianhydride in NMP. The concentration of terminal amino groups was determined by an acid-base titration. The thermal property of poly(urea-imide) was evaluated by thermogravimetric analysis (TGA). Initial decompisition took place at 332-$350^{\circ}C$.

Chemically Induced High Pretilt Angle by CN-Containing Polyimide

  • Lee, Myong-Hoon;You, Kwon-Il;Lee, Chang-Jin;Woo, Tae-Ha
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.191-192
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    • 2000
  • New copolyimides containing nitrile side group were synthesized from copolymerization of pyromellitic dianhydride, m-phenylene diamine and 3,5-diaminobenzonitrile and subsequent thermal imidization of the resulting poly(amic acid). Crystallinity, glass transition temperature and initial decomposition temperature of copolyimides were almost identical to those of homo polyimide prepared from PMDA and m-PDA. Change of pretilt angle induced by the orientation layer of resulting copolyimide was investigated by using a nitrile-containg nematic liquid crystal cell after rubbing. As the content of polar nitrile group was increased in the copolymer, pretilt angle was increased from $3.65^{\circ}$ to $6.49^{\circ}$. The mechanism of this was speculated as the dipolar interaction between the liquid crystal and nitrile groups in copolyimide.

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