• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.481-483
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• 1998

The problem of production of new materials based on polyheteroarylenes and other polymers combining good mechanical and dielectric properties. radiation and chemical stability with heat- and thermal stability is related with the development of efficient synthesis technique of starting low-molecular compounds. Alicyclic dianhydrides are believed to be the promising monomers to synthesize various polymers.

• Elastomers and Composites
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• 제53권2호
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• pp.86-94
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• 2018

The effect of the NCO index and catalyst type on the thermal stability of poly(urethane-isocyanurate) (PUIR) foams was investigated to identify a method for enhancing the flame resistance of PUIR. PUIR foams were prepared using 4,4-diphenylmethane diisocyanate (MDI) and [(diethylene glycol)adipate]diol, which were synthesized by esterification of adipic acid and diethylene glycol. Dabco K-15, Dabco TMR-30, and Toyocat RX-5 were used as the catalysts for trimerization and gelation. The amount of urea and isocyanurate groups in PUIR was semi-quantitatively determined by normalizing their absorbance with the phenyl absorbance measured by FT-IR. The normalization data showed that Dabco TMR-30 effectively generated isocyanurate groups in PUIR. As a result, Dabco TMR-30 effectively raised the decomposition temperature and increased the 800 K and 900 K residues of the PUIR foam synthesized with an NCO index of 200.

• Macromolecular Research
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• 제12권1호
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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.

• Macromolecular Research
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• 제15권1호
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• pp.10-16
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• 2007

In this work, we prepared epoxy/BMI composites by using N,N'-bismaleimide-4,4'-diphenylmethane (BMI), epoxy resin (diglycidyl ether of bisphenol-A (DGEBA)), and 4,4'-diamino diphenyl methane (DDM). The thermal properties and water sorption behaviors of the epoxy and BMI composites were investigated. For the epoxy/BMI composites, the glass transition and decomposition temperatures both increased with increasing BMI addition, which indicates the effect of BMI addition on improved thermal stability. The water sorption behaviors were gravi-metrically measured as a function of humidity, temperature, and composition. The diffusion coefficient and water uptake decreased and the activation energy for water diffusion increased with increasing BMI content, indicating that the water sorption in epoxy resin, which causes reliability problems in electronic devices, can be diminished by BMI addition. The water sorption behaviors in the epoxy/BMI composites were interpreted in terms of their chemical and morphological structures.

• Carbon letters
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• 제23권
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• pp.48-54
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• 2017

This research considers the effect of added mesophase pitch (MP) as an additive during the pitch synthesis reaction of pyrolyzed fuel oil (PFO). Two effects are generated by adding MP. One is an enhancement of thermal stability due to the high thermal property of the additive; the other is that the volatile compounds that were removed by vaporization of PFO during the thermal reaction can participate in the pitch synthesis reaction ($PFO{\rightarrow}pitch$) more efficiently. The effect differs according to the amount of the additive. When the amount of the additive is less than 7 wt%, the first effect is dominant, whereas the second effect is dominant when the additive amount exceeds 10 wt%.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3794-3796
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• 2010

• Macromolecular Research
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• 제15권4호
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• pp.357-362
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• 2007

Polyimide/carbon nanotube (CNT) composite films, for potential use in high performance microelectronics and aerospace applications, were prepared by mixing a polyisoimide (PII) solution and a CNT suspension in NMP, followed by casting, evaporation and thermal imidization. The CNTs were modified by a nitric acid treatment to improve the thermal and electrical properties, as well as to provide good dispersion of the CNTs in a polymer matrix. The formation of functional groups on the modified CNT was confirmed by Raman spectroscopy. Scanning electron microscopy revealed the modified CNTs to be well dispersed in the polyimide matrix, with a uniform diameter of ca. 50 nm. The thermal stability of the films containing the CNTs was improved due to the enhanced interfacial interaction and good dispersion between the polyimide matrix and modified CNTs. In addition, the thermal expansion coefficient of the composites films was slightly decreased, but the dielectric constants increased linearly with increasing CNT content.

• 공업화학
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• 제10권7호
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• pp.1046-1051
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• 1999

잠재성 양이온 개시제인 N-benzylpyrazinium hexafluoroantimonate (BPH)가 1 wt % 첨가된 diglycidylether of bisphenol A(DGEBA)/trimethylolpropane triglycidylether(TMP) 에폭시 블렌드의 혼합 조성비에 따른 경화거동과 열안정성에 대해 각각 DSC와 TGA를 통해 조사하였다. 블렌드계의 잠재 특성은 동적 DSC를 이용하여 온도의 증가에 따른 전환율을 구하여 측정하였다. 동적 DSC에 의한 경화 반응의 열분석 결과 경화 반응 초기에는 DGEBA 수지내의 수산기와 BPH, 그리고 에폭사이드와 BPH 사이의 반응에 의해 저온쪽에 약한 피크를 나타내며 고온쪽에는 3차원 가교 구조를 이루는 성장 과정에서의 발열 피크를 나타냄을 알 수 있었다. 경화 반응 기구의 등온 열분석 결과 경화 반응 속도는 TMP 단일 조성에서보다 DGEBA의 함량에 따라 증가하였다. 경화된 에폭시 수지의 열안정성은 DGEBA 함량이 증가할수록 증가하였는데 이는 DGEBA의 안정한 방향족 구조, 수산기의 존재 그리고 높은 분자량의 영향 등으로 설명할 수 있다.

• 접착 및 계면
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• 제14권3호
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• pp.146-159
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• 2013

본 연구에서는 $350^{\circ}C$에서 4 min 이내로 빠르게 등온 안정화공정을 통해 얻어진 레이온직물의 화학조성, 물리적 특성, X-선 회절 패턴, 열안정성 그리고 직물 형상에 미치는 초음파세척 및 화학전처리의 영향을 조사하였다. 안정화공정 동안 레이온직물에서 발생하는 중량감소와 열수축을 줄이고 안정화반응을 촉진시키기 위하여 안정화공정 전에 레이온직물을 먼저 초음파 세척하고 $NH_4Cl$, $Na_3PO_4$, $H_3PO_4$ 및 $ZnCl_2$로 화학전처리 공정을 수행하였다. 결과는 초음파세척 및 화학전처리가 안정화된 레이온직물의 중량감소, 열수축, 미세구조 변화, 탄소함량, 열안정성, 및 직물 형상에 영향을 주었으며, 사용한 안정화시간과 화학전처리제의 종류에 의존하였다.

• 대한화학회지
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• 제18권6호
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• pp.443-446
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• 1974

內然機關에서 採取한 廢油를 黃酸白土 處理하여 얻어진 再生油는 원래 들어 있던 添加劑, 特히 酸化防止劑와는 相關없이 酸化安定性이 좋아졌다. 이러한 性質의 改善은 芳香族化合物이 거의 25%나 增加하는 事實로 미루어 耐酸化性物質의 生性에 基因하는 것으로 考察된다.