• Polymer(Korea)
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• v.28 no.6
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• pp.494-501
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• 2004

A new alkali developable photosensitive poly(amic acid) (PAA-0) with transmittance at 400 nm was synthesized from cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2-(methacryloyloxy)ethyl-3,5-diamino-benzoate and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyl disiloxane in N-methyl-2-pyrrolidinone. Photosensitivity of the PAA-0 was investigated at 365-400 nm in the presence of a photoinitiator using a high pressure mercury lamp. The photo-cured poly(amic acid) was insoluble toward aqueous 2.38 wt% tetramethylammonium hydroxide solution. Negative pattern of the PAA-0 with 25 ${\mu}{\textrm}{m}$ resolution was obtained by developing with 2.38 wt% tetramethylammonium hydroxide solution after exposure of 600 mJ/$\textrm{cm}^2$ in the presence of 2,2-dimethoxy-2-phenyl-acetophenone as a photoinitiator. The patterned poly(amic acid) was converted to polyimide by thermal curing at 25$0^{\circ}C$ for 50 min, which showed chemical resistance against photoresist stripper as well as good transmittance at 400 nm.

• Elastomers and Composites
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• v.42 no.3
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• pp.177-185
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• 2007

Polyamic acid(PAA)/organoclay nanocomposites containing phosphorous were prepared by solution blending of phosphorylated PAA(PPAA) and organically modified montmorillonite(O-MMT) as a type of layered clays. The nanocomposites were characterized by FT-IR, DSC, TGA, PCFC, SEM, and XRD. The preparation of nanocomposites was confirmed by FT-IR and XRD. SEM pictures showed that the organoclay was dispersed well in the PAA matrix relatively. XRD results indicated that the O-MMT layers were intercalated. The thermal stability and flame retardancy of O-MMT/PPAA nanocomposites were higher than those of pure PAA. PCFC results also showed that the heat release capacity and total heat release values of O-MMT 4 wt%/PPAA-0.2, 0.4, 0.6 composites were decreased with increasing the mole ratio of phosphorous. It was found that the nanocomposite films had the potential to be used as a fire safe material.

• Polymer(Korea)
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• v.36 no.4
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• pp.448-454
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• 2012

A poly(amic acid) (PAA) was prepared by reaction of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluropropane (BAPP) in N,N-dimethylacetamide (DMAc). The cast films of the synthesized PAA were thermally treated at different temperatures to create polyimide (PI) films. The heat treatment temperature varied between 80 and $230^{\circ}C$ to investigate the imidization index in relation with the solvent evaporation rates. The progress of PAA imidization was examined using a thermogravimetric analyzer (TGA) and a Fourier transform infrared spectroscope (FTIR) at various time and temperature. The experimental results showed that the imidization index was fast at the initial stage in the presence of solvent, DMAc, reaching the final imidization. When the imidization temperature is high over $200^{\circ}C$, the imidization index decreased because the solvent was evaporated too fast.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.343-346
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• 2008

2,2-BIs (3,4-anhydrodicarboxyphenyl)hexafluoropane(6FDA)와 4-aminophenyl sulfone(4APS), 3-aminophenyl sulfone(3APS)를 사용하여 Polyimide(PI)의 전구체인 Poly(amic acid)(PAA)를 합성하였다. 그 후 PAA의 용해도를 측정 하였다. 그리고 PAA에 열을 가하여 PI로 경화됨을 FT-IR을 이용하여 확인 하였다.

• 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.

• Textile Coloration and Finishing
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• v.35 no.4
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• pp.221-230
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• 2023

Meta-aramid and polyamic acid were separated and the manufactured films were analyzed for their integration and logarithmic properties. The miscibility of meta-aramid and polyamic acid was analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy. Using calorimetric analysis and differential scanning calorimetry, the storage of meta-aramid and polyamic acid, indicated on the right side of the column, was analyzed. It was confirmed that the initial thermal resistance occurs because the polyamic acid is accounted for in the meta-aramid, and the glass transition temperature and persistence phenomenon are explained.

• Membrane Journal
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• v.3 no.2
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• pp.60-69
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• 1993

The polyamic acid (PAA) based on 3,3', 4,4'-benzophenonetetracarboxylic dianhydride(BTDA)-3,3', 4,4'-dipheylsulfonetetracarboxylic dianhydride(BAPP), 2,2-bis(4-[4-aminophenoxyl]phenyl) propane(DSDA)-3,3', 4,4'-dipheylsulfonetetracarboxylic dianhydride(BAPP), and 3,3',4,4'-benzophenonetetracarboxylic dianhydride(BTDA)-4,4'-oxydianiline(4,4'-ODA) was synthesised. The casted PAA films were partially imidised and the permeation properties of these PAA films for $O_2$ and $N_2$ were investigated according to the degree of imidisation. When the degree of imidisation was increased by curing, the permeabilities of the PAA films were increased for a while and then decreased. These results show that the increase of gas permeation by the disappearence of strong hydrogen bond is larger than the decrease of gas permeation by the dense effect. The decrease of hydrogen bond between molecular chains of PAA suddenly increases the vibration of the chain to make holes but the compaction in polymer chain gradually decreases the gas permeation. The largest values of permeability of BTDA-BAPP, DSDA-BAPP and BTDA-4,4'-ODA film was 8.3, 0.3 and 0.8 barrer respectively, and the imidisation content corresponding to the values of the largest permeability was 37, 47 and 55% each. But the permselctivities of the PAA films were not changed by the variation of the degree of imidisation.

• Polymer(Korea)
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• v.34 no.5
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• pp.480-484
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• 2010

A series of poly(amic acid)s(PAAs) was prepared by reacting 4,4'-(4,4'-isopropylidenediphenoxy) bis(phthalic anhydride)(BPADA) as the anhydride monomer and 2,2'-bis(trifluoromethyl) benzidine (TFB), bis(3-aminophenyl)sulfone (APS), 4,4'-methylenebis-(2-methylcyclohexylamine) (MMCA), or bis[4-(3-aminophenoxy) phenyl] sulfone (BAPS) as the amine monomer with 5 mol% melamine in N,N-dimethylacetamide (DMAc). Colorless and transparent polyimide (PI) films were obtained by casting the PAAs at various heat treatment temperatures. The thermo-mechanical properties and optical transparency of the PI films were investigated. The thermal properties of the PI films were examined using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA), and their optical transparency were measured by spectrophotometry. The coefficient of thermal expansion (CTE) and yellow index (YI) values of all samples were in the range of $48.53-64.24ppm/^{\circ}C$ and < 3.0, respectively.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.359-362
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• 2007

본 실험에서는 Polyimide (PI)의 전구체인 Poly(amic acid) (PAA)의 제조를 위하여 2,2-BIs(3,4-anhydrodicarboxyphenyl)hexafluoropane(6FDA)와 4-aminophenyl sulfone로 PAA를 합성하였다. 이를 열을 가하여 Polyimide가되는 반응을 적외선 분광법을 이용하여 추적하였다. 이미드화 반응은 $80^{\circ}C$에서 1시간, $120^{\circ}C$에서 1시간, $240^{\circ}C$에서 1시간, $250^{\circ}C$에서 1시간, 2경화시킴으로 완결됨을 확인하였다.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.320-326
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• 2013

In this study, various polyimide films were synthesized via low temperature cure in order to understand changes in their physical properties when using 4,4'-oxydianiline (ODA) as a diamine and dianhydride molecules with different backbones on a single diamine such as 4,4'-Oxydiphthalic anhydride (ODPA), 4,4-hexafluoroisopropylidene diphthalic dianhydride (6FDA), and 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA). After the synthesis of poly(amic acid), polyimide films were fabricated by adding 1,4-diazabicyclo [2.2.2]octane (DABCO), a low-temperature catalyst, at various wt% to poly(amic acid)s. Changes of optical and thermal properties were compared and analyzed between polyimide films without catalyst and polyimide films with catalyst by FT-IR, UV-Vis transmittance, DSC/TGA, and WAXD analysis. Wide-angle X-ray diffraction (WAXD) analysis revealed that the mean intermolecular distance decreased with the use of a catalyst by the type of dianhydride. Thus, while the optical properties of the films improve by a low-temperature cure performed using a catalyst, their thermal properties decrease. These changes can be explained by the changes in the morphological structure of the films triggered by a catalyst-induced reduction in the mean intermolecular distance. Moreover, the results show that the type of dianhydride determines the degree of change in the optical and thermal properties in each types of polyimide, demonstrating that changes in the optical and thermal properties are directly associated with the backbone of the polyimide structure.