• Title/Summary/Keyword: polyimide(PI)

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Polyimide grafted magnesium hydroxide for $CO_2$ Adsorption (폴리이미드 그라프팅 수산화마그네슘의 이산화탄소 흡수)

  • Hemalatha, Pushparaj;Ganesh, Mani;Peng, Mei Mei;Kim, Dea-Kyung;Jang, Hyun-Tae
    • Proceedings of the KAIS Fall Conference
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    • 2011.12a
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    • pp.364-366
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    • 2011
  • Polyimide (PI) grafted magnesium hydroxide was synthesised and characterised by XRD, TGA, SEM analysis. XRD patterns of $PI/Mg(OH)_2$ carried the peaks due to $Mg(OH)_2$ with decreased intensity. The $CO_2$ adsorption capacity of $PI/Mg(OH)_2$ at $50^{\circ}C$ was found to be 14 wt% revealing chemisorption of $CO_2$ on $Mg(OH)_2$ which could be regenerated at higher temperatures.

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Preparation and Properties of Polyimides Having Highly Flexible Linkages and Their Nanocomposites with Organoclays

  • Cho, Young-Ho;Park, Jong-Min;Park, Yun-Heum
    • Macromolecular Research
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    • v.12 no.1
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    • pp.38-45
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    • 2004
  • A highly flexible polyimide (PI) was synthesized successfully from ethylene glycol bis(anhydrotrimellitate) (TMEG) and 1,3-bis(4-aminophenoxy)benzene (TPER) for its application in electronics. To enhance the thermal stability and mechanical properties of this novel PI, we prepared PI nanocomposite films using nanoparticles of clays that had been treated with organic intercalating agents (organoclays). We used two types of organoclays: montmo-rillonite (MMT) treated with hexadecylamine (C$\_$16/) and MMT treated with dimethyl dihydrogenated tallow quaternary ammonium (l5A). PI/organoclay hybrid films were obtained by first preparing poly(amic acid) (PAA)/organoclay films and then converting the PAA to polyimide by thermal conversion. PAA was characterized by FT-IR and $^1$H-NMR spectroscopy and the conversion of PAA to PI was confirmed by FT-IR spectroscopy. We analyzed the dispersion of the organoclays in the PI film by X-ray diffraction. The thermal stability and mechanical properties of the hybrid films were also investigated.

Preparation and dielectric properties of polyimide thin films by vapor deposition polymerization method (진공증착중합에 의한 Polyimide 박막의 제조와 유전특성)

  • 이덕출;김형권
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.3
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    • pp.380-385
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    • 1996
  • Thin films of polyamic acid(PAA) were fabricated by vapor deposition polymerization(VDP) from pyromellitic dianhydride(PMDA) and 4,4'-diamino diphenyl ether(DDE). Thin films of polyimide(PI) were obtained by curing PAA, and their dielectric properties have been measured. The uniform thin films of PI formed by curing PAA at 300 .deg. C for 1 hr. which was confirmed by Fourier transform Infrared spectroscopy(FT-IR) absorption at 720, 1380, 1780c $m_{-1}$. Relative permittivity and tan .delta. were 3.9 and 0.008 at 10kHz, respectively. (author). 8 refs., 11 figs., 1 tab.1 tab.

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Control of Pretilt Angle using a in-situ Photoalignment Method on Photo-crosslinkable Polymer Surface (광중합 가능한 폴리머 표면에 in-situ 광배향법을 이용한 프리틸트각 제어)

  • 정은아;황정연;서대식;김재형;한은주
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.350-353
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    • 2001
  • Aligning capabilities for nematic liquid crystal (NLC) using a in-situ photodimerization method on various Photo-crosslinkable polyimide (PI) based Polymer and blending photopolymer surfaces were studied. High pretilt angle of the NLC can be measured by obliquely polarized UV exposure on a photo-crosslinkable polyimide based polymer surface containing biphenyl (BP), decal (de), and cholesterol (chol) group, respectively. However, the low pretilt angle of the NLC was measured by obliquely polarized UV exposure on the blending photopolymer (PI and cinnamate materials) surfaces. Consequently, the pretilt angle of the NLC generated on the photo-crosslinkable polyimide based polymer surfaces using the in-situ photodimerization method was higher than that of the blending photopolymers.

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Research on the Adhesion of Flexible Copper Clad Laminates According to Species of Polyimide (폴리이미드 종류에 따른 연성 동박 적층판의 부착력 연구)

  • Lee Jae Won;Kim Sang Ho
    • Journal of the Korean institute of surface engineering
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    • v.38 no.2
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    • pp.49-54
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    • 2005
  • Flexible copper clad laminates (FCCL) fabricated by sputtering has advantages in fine pitch etching and dimensional accuracy than previous casting or laminating type FCCL, But its lower adhesion is inevitable technical challenge to solve for commercializing it. Chromium (Cr) which strongly reacts with O moiety was used as tie-coating layer in order to improve low adhesion between copper (Cu) and polyimide (PI). Sputtering raw polyimide (SRPI) and casting raw polyimide (CRPI) were used as substrates at this research. PI was pretreated by plasma before sputtering, and each sample was varied with RF power and Cr thickness on sputtering. Peel strength of the FCCL on SRPI was higher than that on CRPI. Adhesion had maximum value when 10 nm of Cr was deposited on SRPI by RF power of 50 W. It seems to be by the formation of Cu-Cr-O solid solution at the metal-PI interface.

The Etching Characteristics of Polyimide Thin Films using CF4O2 Gas Plasma (CF4O2 gas 플라즈마를 이용한 폴리이미드 박막의 식각)

  • 강필승;김창일;김상기
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.5
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    • pp.393-397
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    • 2002
  • Polyimide (PI) films have been studied widely as the interlayer dielectric materials due to a low dielectric constant, low water absorption, high gap-fill and planarization capability. The polyimide film was etched using inductively coupled plasma system. The etcying characteristics such as etch rate and selectivity were evaluated at different $CF_4/(CF_4+O_2)$chemistry. The maximum etch rate was 8300 ${\AA}/min$ and the selectivity of polyimide to SiO$_2$was 5.9 at $CF_4/(CF_4+O_2)$ of 0.2. Etch profile of polyimide film with an aluminum pattern was measured by a scanning electron microscopy. The vertical profile was approximately $90^{\circ}$ at $CF_4/(CF_4+O_2)$ of 0.2. As 20% $CF_4$ were added into $O_2$ plasma from the results of the optical emission spectroscopy, the radical densities of fluorine and oxygen increased with increasing $CF_4$ concentration in $CF_4/O_2$ from 0 to 20%, resulting in the increased etch rate. The surface reaction of etched PI films was investigated using x-ray photoelectron spectroscopy.

Annealing Behavior of Pretilt Angles on Polyimide Surface with Rubbing and Ion Beam Irradiation

  • Lee, Sang-Keuk;Lim, Ji-Hun;Oh, Byeong-Yun;Kim, Young-Hwan;Han, Jeong-Min;Seo, Dae-Shik
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.6
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    • pp.243-246
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    • 2008
  • We have studied the liquid crystal (LC) alignment, the pretilt angle generation, and the annealing behavior for a nematic liquid crystal (NLC) on the homogeneous polyimide (PI) surfaces by using the rubbing method and the ion beam (IB) method. An excellent LC alignment of the NLC on the PI surface with rubbing and IB irradiation were observed. The pretilt angle of NLC on the homogeneous PI surface for the rubbing method is decreased from $4.5^{\circ}$ to $3.5^{\circ}$ as rubbing time is increased, that of the for the IB irradiation method is decreased from $0.5^{\circ}$ to $0.1^{\circ}$ as the time of IB irradiation is increased. After the annealing, the pretilt angles of the rubbed PI surfaces increased up to $4^{\circ}$, these of the IB irradiated PI surfaces little increased. It is considered the side chain of the rubbed PI show the its abilities of the original capacities, while the side chain of the IB irradiated PI cannot show the its abilities of the original capacities due to the IB has already destroyed the side chain of the PI.

Si Induced Polymer Based Alignment Layer for Liquid Crystal Orientations with High Electro-Optic Properties at Low Temperature (저온 공정의 Si을 이용한 PI 배향 막의 전기광학 특성 향상에 대한 연구)

  • Kim, Dai-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.9
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    • pp.677-681
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    • 2013
  • Apart from the deposition of alignment layer, alignment process needs to be involved for alignment of liquid crystal (LC) molecules. To simplify manufacturing process, several method were used such as rubbing, ion-beam irradiation, UV irradiation, and lithography. But, eventually it needs another treatment for LC alignment. Here, we suggested Si induced polyimide (PI) alignment layer at low temperature. Using this method, we are able to eliminate the alignment process and found that the alignment and electro-optic performance are much better than that of the rubbed PI LC cells. Compared to the rubbed PI cells, the response time was decreased by 70% and C-V characteristics have hysteresis-free.

Washing Effects on Generation of Pretilt Angle in NLC, 5CB, on a Polyimide Surface with Trifluoromethyl Moieties

  • Lee, Sang-Keuk;Hwang, Jeoung-Yeon;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.04a
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    • pp.133-135
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    • 2003
  • The washing effects on pretilt angle generation in a nematic liquid crystal (NLC), 4-n-pentyl-4’-cyanobiphenyl (5CB) on a rubbed polyimide (PI) surface with trifluoromethyl moiety have been successfully studied. The pretilt angle of 5CB is increased by the washing process on the rubbed PI surface. The surface tension on the rubbed PI surface increases with the rubbing strength RS and then saturated above RS=150 mm. The pretilt angle of 5CB for all washing processes on the rubbed PI surface decreases with the surface tension. We have found that the pretilt angle of 5CB on the rubbed PI surface may be attributed van der walls (VDW) dispersion interaction between the LC molecules and the polymer surfaces having trifluoromethyl moieties.

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A Study on Response Characteristics of TN Cell on a Polyimide Surface (폴리이미드 표면에서의 TN 셀의 응답 특성에 관한 연구)

  • 황정연;전용제;정연학;서대식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.9
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    • pp.808-811
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    • 2002
  • We investigated response characteristics of twisted nematic (TN) cell with different nematic liquid crystals (NLCs) and cell gap d on a rubbed polyimide (PI) surface. High transmittance and fast response time of the TN cell on the rubbed PI surface were achieved by using high birefringence (Δn) and low cell gap d. The response time of TN cell on the rubbed PI surface was measured 5.1 ms. The transmittance and response time of the TN cell on the rubbed PI surface decreased with decreasing Δnd.