• Elastomers and Composites
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• 제46권4호
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• pp.295-303
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• 2011

3,3'-dihydroxybenzidine 과 2,2-bis (3-amino-4-hydroxyphenyl)hexafluoro-propane을 포함하는 두가지 타입의 bis(o-aminophenol)s 과 imide-diacids 를 직접 축 중합하여 imide 고리를 포함한 새로운 방향족 polyhydroxyamides(PHAs)을 합성하였다. 모든 중합체들은 FT-IR, FT-NMR, DSC 및 TGA를 이용하여 조사하였다. 중합체들의 고유점도는 $35^{\circ}C$의 DMAc 용액에서 측정하였으며, 0.49-1.13 dL/g 을 보였다. PHA 1을 제외한 PHA 2 와 3은 DMF, DMAc, NMP 등 극성 용매에 잘 용해되었으며, 6F 그룹이 포함된 PHA 4, 5, 및 6은 극성이 낮은 용매에 대해서도 좋은 용해도를 보였다. 반면에 polybenzoxazoles(PBOs)은 황산에 일부 용해되는 것 외에 다양한 용매에도 용해되지 않았다. 질소분위기 하에서 PBO 1, 2, 3의 최대 열분해온도는 $650-656^{\circ}C$ 범위의 값들을 보였고, char 수득율도 57.4-61.9 %로 비교적 높은 값을 보였다. 이로부터 고분자 주 사슬에 imide 혹은 diimide 고리의 도입은 PHA 혹은 PBO의 열안정성을 높이는데 효과적임을 알 수 있었다.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.39-45
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• 1997

Introduction : Polyimides are one of the most important classes of the high performance polymers due to their excellent electrical, thermal, and high-temperature mechanical properties. But their uses are limited because of their poor solubility. Most polyimide derivatives are processed in the form of polyamic acids, which are subsequently converted into the imide structures.Recently, it has been found that the soluble polyimides with large molecular weight sufficient to application. For enhancing processability, the majority of approaches have involved the following factors. As much as, the separation of the imide ring along the back-bone, that is to say, reducing the density of imide ring in the repeat structure. The introduction of bulky substituents along the back-bone, in order to enhance the free volume of main-chain. The incorporation of flexible or thermally stable linkages in the main-chain, reducing the packing force. The disruption of symmetry or recurrence regularity through copolymerization in order to reduce crystallnity.The objectives of this investigation are the synthesis and characterization of soluble polyimides as membrane materials by the single-step polymerization and the preparation of the asymmetric polyimide membrane by using phase inversion technique. In the present study, three series of polyimide derivatives are synthesized; H series is homopolyimides, A series is prepared from single dianhydride and two diamines, B series is yielded from two dianhydrides and a diamine. The dope solution was directly prepared from the PI solution via one step polymerization from monomers.

• Elastomers and Composites
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• 제51권3호
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• pp.195-205
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• 2016

A series of aromatic poly(hydroxyamide)s (PHAs) containing varying oligo(oxyethylene) substituents and 1,3-phenylene imide ring unit in the main chain were synthesized by the direct polycondensation reaction. The inherent viscosities of the PHAs exhibited in the range of 0.89~1.12 dL/g in DMAc or DMAc/LiCl solution. The PH-2~5 copolymers were easily soluble in strong aprotic solvents: DMAc, NMP, DMSO etc. and the PH-5 copolymer was soluble in less polar solvents such as m-creasol and pyridine with LiCl salt on heating. However, all PBOs were quite insoluble in other solvents, but only partially soluble in sulfuric acid. All copolymers (PH-2~5) could afford the flexible and tough films by solution casting. We identified that the PHAs were converted to the PBOs by the thermal cyclization reaction in the range of $200{\sim}380^{\circ}C$. The 10% weight loss temperatures and char yields of the PBOs were recorded in the range of $382{\sim}647^{\circ}C$ and 38.7~73.1% values at $900^{\circ}C$. The tensile strength and initial modulus of the PH-5 in the copolmers showed the highest values of 2.46 GPa and 49.55 MPa, respectively. The LOI values of the PHAs were in the range 26.6~29.0%, and increased with increasing 1,3-phenylene imide ring unit.

• Fibers and Polymers
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• 제2권2호
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• pp.92-97
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• 2001

New film forming aromatic poly(amide-imide)s containing isoindoloquinazolinedione (IQ) unit in the backbone chain (polymer XIV) have been successfully synthesized by preparing prepolymers of poly(amic acid-carbonamide). followed by subsequent thermal cyclization of the prepolymers. 4,4-Diamino-3-carbamoylbenzanilide (DACB) V has been synthesized by reduction of 3-carbamoyl-4-amino-4-nitrobenzanilide IV. The prepolymers of poly(amic-acid-carbonamide) (polymers VII and VIII) which exhibit viscosities ranging from 1.4 to 1.7 dl/g have been prepared by a condensation polymerization of monomers such as BPDA, ODA, and DACB. Polymer XIV has been obtained by thermal cyclization of the polymers VII and VIII. During the thermal cyclization reaction, imide ring structure was first introduced and then transformed to the structure of IQ unit. The thermal degradation rate of the resultant polymers were influenced by the cleavage of amide bond but the final char yield was comparable to that of poly(BPDA-ODA).

• Elastomers and Composites
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• 제43권1호
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• pp.39-48
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• 2008

상용 에폭시 수지의 접착력은 XNBR을 첨가함으로써 달성할 수 있으나 이는 필연적으로 유리전이온도(Tg)의 감소를 수반하여 접착제의 내열성을 저하시킨다. 1,3-bis(3-aminopropyl) tetramethyldisiloxane과 hydroxy phthalic anhydride를 반응시켜 siloxane-imide를 합성하고, 이를 상용 에폭시 수지와 공중합시켜 변성 에폭시 수지를 합성하였다. 변성 에폭시 수지의 siloxaneimide 함량을 결정하기 위하여 접착력 및 유리전이온도를 2관능성 에폭시 수지의 경우와 비교하여 조성비를 정하였다. Siloxane-imide와 공중합된 30% 변성 에폭시 수지는 5% XNBR을 첨가한 경우 0.42 N/mm의 박리 강도와 $155^{\circ}C$의 유리전이온도를 나타내어 die-bond용 접착제에 요구되는 물성 값인 0.3 N/mm 이상의 박리 강도와 $150^{\circ}C$ 이상의 유리전이온도를 충분히 만족 시킴을 알 수 있었다. 변성 에폭시 수지의 내 산성, 내 알칼리성 및 내습성을 평가한 결과 벤젠 링과 이미드 링의 영향으로 산, 염기 조건에서는 상용 에폭시 수지 대비 무게 변화폭이 감소하였지만 수분 조건에서는 무게 변화폭이 증가한 것을 알 수 있었다. 5% XNBR을 첨가한 30% 변성 에폭시 수지의 경우, 인장응력과 신장률이 상용 에폭시 수지 대비 약 220% 향상되었는데 이는 siloxane의 유연한 성질 때문인 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.357-362
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• 2003

The pathway producing imide ring closure during the thermal imidization of poly(amic acid) (PAA) was investigated in detail using a new analytical method, two-dimensional (2D) Raman correlation spectroscopy. The signs of the cross peaks in synchronous spectra provided evidence of the thermal imidization of PAA into PI as the heating temperature increased. The signs of the cross peaks in asynchronous spectra suggested that the imide-related modes changed prior to the amide or carboxylic mode, which indicates that cyclization occurred before the amide proton was abstracted.

• 한국염색가공학회지
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• 제7권4호
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• pp.39-44
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• 1995

A study has been made about some correlations in the chemical cyclization of precursors, poly(ether-amide-amic acid)s by treating in solution a mixture of acetic anhydride and pyridine in the presence of 4,4-dimethyl formamide, with the poly(ether-amic acid)s being respectively reacted between trimellitic anhydride chloride and 3 kinds of diamines, i.e., 4,4'-bis(m-aminophenoxy) benzophenone, 2,2'-bis[4-(m-aminophenoxy) phenyl] propane and 4,4'-bis(m-aminophenoxy) diphenyl sulfone. The cyclization of imide ring in the poly(ether-amide-amic acid)s may be regarded as an intramolecular acylation of amide group by o-carboxyl group. As a result of this reseach, the effects on the conversion to poly(ether-amide-imide)s have been found by changing the ratio of cosolvents in the cyclization mixture.

• 공업화학
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• 제3권1호
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• pp.179-187
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• 1992

Poly(styrene-co-maleic anhydride), SMA를 DMF 용매에 약 10%(w/w) 용액으로 한 다음 aniline, p-toluidine 및 p-chloroaniline 등으로 maleic anhydride 반복 단위를 imide화 하였다. 이미드화에 있어서 환화 탈수제(cyclodehydration agents)를 사용하였으며 최적 반응조건은 다음과 같았다. (a) 반응온도 : $80^{\circ}C$ (b) 환화 탈수제의 몰비 : SMA내 anhydride/acetic anhydride/sodium acetate/triethyl amino = 1.0/2.0/0.2/1.1. 생성된 imide-modified SMA (SMI) 시료들은 이미드화도가 증가됨에 따라 $T_g$가 증가하였으나 그 변화 정도는 크지 않았다. SMI의 $T_g$는 이미드화에 사용된 아민의 종류에 따라 aniline < p-toluidine < p-chloroaniline의 순으로 $T_g$가 증가하였다.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3074-3080
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• 2011

We synthesized three novel poly(norbornene bisimide)s by ring opening metathesis polymerization (ROMP) and subsequent hydrogenation. Their thermal, mechanical and optical properties were investigated with TGA, DMA, UV-Vis spectrometer, and optical reflectometer. The new polymers showed high glass transition temperatures over $260^{\circ}C$ and good thermal stability with 5% wt-loss temperature higher than $390^{\circ}C$. When solvent casted, they yielded optically transparent and dimensionally stable films with a relatively low coefficient of thermal expansion of about 50 ppm $K^{-1}$. Therefore, the bisimide moieties substantially enhanced thermal and dimensional stabilities, as compared with normal ROMP-prepared polynorbornene films. Though the water uptake was increased to 0.6 wt-%, this water uptake is still considerably lower than that for polyethersulfones (1.4 wt-%) or polyimides (2.0 wt-%). Hence, the new poly(norbornene bisimide)s may become attractive candidates for flexible substrates of optoelectronic devices such as displays and photovoltaic solar cells.

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1542-1548
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• 2006

Maleimide modified epoxy compounds were prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with diglycidylether of bisphenol-A. Triphenylphosphine was used as catalyst and methylethylketone as solvent. The resulting compound possessed both the oxirane ring and maleimide group. The curing reaction of the maleimide epoxy compound with amine curing agents such as 1-(2-aminoethyl) piperazine (AEP) and 5-amino-1,3,3-trimethylcyclohexane methylamine isophorone diamine, IPDA) were studied. Incorporation of maleimide groups in the epoxy resin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples were found to have good thermal stability, chemical resistance (acid/alkali/solvent) and water absorption resistance.