• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.1188-1192
• /
• 2004

Polyamic acid precursors were prepared by mixing various main chain dianhydrides, main chain diamines and side chain diamines. Copolyimide films with alkylcyclohexylbenzene as a side chain were prepared by thermal imidization of polyamic acid precursors. Pretilt angles on rubbed polyimides changed according to the side chain and main chain structures of the polyimide. Consequently, we found that LC pretilt angles of polyimide films with a liquid crystal structure as a side chain showed to be approximately 90$^{\circ}$ when a linear and rigid polyimide main chain and a side chain of suitable length were employed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
• /
• pp.174-177
• /
• 1993

The polyimide films were prepared by imidizing the polyamic acid long-chain alkylamine (dimethylhexadecylamine) salt films with a thermal and chemical treatment, where the polyamic acid alkylamine salt film were formed on various substrates by using Langmuir-Blodgett (LB) method. The imidization of polyamic acid alkylamine salt films with various thickness were identified with FT-IR and UV-visible absorption spectroscopies. Atomic Force Microscopy (AFM) have been used to investigate the surface morpology of polyamic acid alkylamine salt and imidized films.

• Macromolecular Research
• /
• 제11권3호
• /
• pp.172-177
• /
• 2003

Biphenyltetracarboximide-phenylene diamine polyimide/silica-titania ternary hybrid composites were Prepared by thermal imidization and sol-gel reaction. Fluorescence spectroscopic, scanning electron microscopy, and atomic force microscopy studies revealed that the addition of small amount of titania showed profound effects on the microstructure and photophysical behaviors of polyimide/silica hybrid composites, when the content of silica-titania mixture was small or when the ratio of silica to titania in the mixture was high.

• Macromolecular Research
• /
• 제10권5호
• /
• pp.241-245
• /
• 2002

A new aromatic diamine monomer containing benzoxazole substituents was prepared by a multi-step synthesis starting from 1,4-dibromo-2,5-difluorobenzene. This bulky and disc-shaped monomer was polymerized with commercial dianhydride monomers to give several different poly(amic acid)s with their inherent viscosities in the range of 0.24-0.35 dL/g. The prepared polymers were soluble in typical polar aprotic solvents. Thermal imidization to the corresponding polyimides were investigated by using FT-IR, DSC and TGA.

• Macromolecular Research
• /
• 제9권5호
• /
• pp.247-252
• /
• 2001

Tricyclic aliphatic dianhydride monomer, tricycle[4.2.2.0]dec-9-ene exo, endo-3,4: 7,8-tetra-carboxylicdianhydride (TCDDA), was synthesized by photochemical reaction and poly(amic acid)s from TCDDA and diamines such as 1,4-bis-(4-aminophenoxy)benzene (BAB), 2,2-bis(4-(4-aminophenoxy) phenyl) propane (BAPP), 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (BAPHF), bis(4-(4-ami-nophenoxy) phenyl)sulfone (BAPS), and 1,4-bis-(4-aminophenoxy)biphenyl (BABP) were prepared. The inherent viscosities of the poly(amic acid)s were between 0.39 and 0.50 dL/g. The poly(amic acid)s were converted to polyimide films by thermal imidization. The glass transition temperatures (T$\_$g/) of the polyimides were in the range of 201-263$\^{C}$. The thermogravimetric analysis (TGA) thermogram of these polyimides showed the temperatures of 5% weight losses between 375 and 393$\^{C}$ in nitrogen atmosphere. To show their utility for image generation, degradations of these polyimides in UV exposure were investigated by UV spectroscopy.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
• /
• pp.191-192
• /
• 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.

• Macromolecular Research
• /
• 제9권6호
• /
• pp.327-331
• /
• 2001

A new soluble photosensitive poly(amide-co-imide) containing p-phenylenediacryloyl moiety was synthesized and its photoreactivity was characterized. The copolymer was synthesized fromp-phenylenediacryloyl chloride, 4,4-(hexafluoroisopropylidene)diphthalic anhydride and two equivalents of bis(4-aminophenyl) ether in NMP with a subsequent chemical imidization of the resulting poly[amide$\xi$ο-(amic acid)] by acetic anhydride and pyridine. The structure and thermal properties of the polymer were characterized by spectroscopic methods and thermal analyses. The polymer was stable up to 350$\^{C}$, showed good solubility in polar aprotic solvents, and became insoluble after UV irradiation due to the[2+2] cycloaddition of phenylenediacryloyl moiety. Photoreactivity of the polymer was investigated in solution or as a film with respect to the various exposure conditions by UV/Vis spectroscopy. The photosensitivity was noticeably increased with the irradiation temperature, especially in the presense of photosensitizer. The reason for the increased sensitivity was speculated based on the flexibilization of main chain at elevated temperature. Exposure characteristic curves were obtained from the gel fraction experiments after UV irradiation. The sensitivity and contrast at 160$\^{C}$ were measured to be 293 mJ/㎠ and 1.64, respectively.

• 폴리머
• /
• 제38권5호
• /
• pp.632-639
• /
• 2014

Trimellitic anhydride chloride와 2,7-dihydroxynaphthalene을 이용하여 2,7-dihydroxynaphthalene bis(trimellitate anhydride) (2,7-TA)의 무수물 단량체를 합성하였다. 합성된 2,7-TA와 p-xylylenediamine 및 2,2'-bis(trifluoromethyl) benzidine(TFB)을 다양한 몰 비로 반응하여 얻은 폴리아믹산(polyamic acid, PAA)을 유리판에서 열처리하여 에스터기를 가지는 폴리이미드 공중합체(copolyimide, Co-PI)를 합성하였다. 합성된 Co-PI는 TFB의 몰 비 조성에 따라 열적 성질, 가스 투과도, 및 광학 성질 등을 조사하였다. 용액 캐스팅으로 합성된 Co-PI 필름은 유연하고 질긴 성질을 보였다. Co-PI 필름은 모두 투명하였으며, 각 필름의 cut-off wavelength은 370~395 nm이었고, 노란색 지수는 3.55~7.63의 비교적 낮은 값을 보여주었다. Co-PI 필름의 열적 성질들은 TFB의 몰 비가 증가할수록 증가하였지만, 산소 차단성과 광학 투명성에서는 반대의 결과를 보여주었다.

• 폴리머
• /
• 제37권5호
• /
• pp.618-624
• /
• 2013

Trimellitic anhydride chloride와 hydroquinone을 이용하여 hydroquinone bis(trimellitate anhydride)(HQ-TA)를 합성하였다. 합성된 HQ-TA와 6가지의 다양한 디아민들을 사용하여 전구체 polyamic acid(PAA)를 합성한 후, 열적-및 화학적-이미드화 반응을 거쳐 에스터 그룹을 가지는 폴리이미드(polyimide, PI) 필름을 합성하였다. PI 합성은 구조적으로 다양한 방향족 디아민을 사용하였다. 각 디아민 구조에 따른 유리전이온도($T_g$)는 167-$215^{\circ}C$를 보였고, 초기분해온도(${T_D}^i$)는 $364-451^{\circ}C$를 나타내었다. 가장 향상된 열팽창 계수(coefficient of thermal expansion, CTE)와 가스차단성은 TFB(3.23 $ppm/^{\circ}C$)와 4,4-ODA(< $10^{-2}cc/m^2/day$) 단량체를 각각 사용하였을 때 보였다. PI 필름의 투과도는 500 nm에서 65-89%를 보였으며, 노란색 정도를 나타내는 황색지수(yellow index, YI)는 3.01-69.52를 보였다.

• 폴리머
• /
• 제39권1호
• /
• pp.88-98
• /
• 2015

폴리이미드(PI) 나노복합체 필름 제조에 사용된 작용기화 4-amino-N-hexadecylbenzamide graphene sheets (AHB-GSs)는 graphene oxide 분산액에 4-amino-N-hexadecylbenzamide(AHB)를 반응시켜 합성하였다. AHB-GS의 주사탐침 현미경(atomic force microscope, AFM) 이미지와 모식도를 통해서 AHB-GS의 평균 두께가 약 3.21 nm임을 확인하였다. PI는 4,4'-biphthalic anhydride와 bis(4-aminophenyl)sulfide를 사용하여 합성하였다. PI 나노복합체는 0-10 wt%의 다양한 함량의 AHB-GS를 용액 삽입(solution intercalation) 방법을 사용하여 합성하였고, 이미드화는 각각 $250^{\circ}C$ 및 $350^{\circ}C$까지 열 처리하였다. AHB-GS는 대부분 고분자 매트릭스에 잘 분산되었고 약간 뭉친 것도 있었지만 마이크로미터 수준의 입자는 관찰되지 않았다. TEM으로 관찰하였을 때, 평균적으로 입자의 두께는 10 nm 미만이었다. PI 복합체 필름 중 소량의 AHB-GS만으로도 가스 투과도와 전기 전도도는 향상되었지만, 반대로 유리전이 온도와 초기 분해 온도는 AHB-GS의 함량이 10 wt%까지 증가함에 따라 지속적으로 감소되는 경향을 보였다. 전체적으로는, $250^{\circ}C$까지 이미드화한 PI에 비해 $350^{\circ}C$까지 열처리한 PI 필름이 보다 향상된 특성을 보였다.