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Morphological investigation of AFR-PEPA-N imide oligomers and their cured polyimides and the remodification of AFR-PEPA-N to achieve liquid-crystalline behaviorMurphy, Lindsay Adams 15 November 2004 (has links)
The morphological investigation of AFR-PEPA-N and the development of a new polyimide have been established herein. AFR-PEPA-N is an imide oligomer that was created out of the need to attain a high temperature polyimide that is also resistant to hygrothermal and thermooxidative degradation. Previously, AFR700B was implemented in aerospace applications, but it was found to be hygrothermally unstable. It experienced a severe drop in its glass transition temperature and composite blistering. AFR700B was improved upon, by altering the chemical structure of the polyimide. The nadic end-cap was removed and replaced by a more hydrolytically stable end-cap. However this phenylethynyl-terminated end-group could possibly create semi-crystallinity or liquid-crystalline characteristics within the polymer.
Previous research suggests further study of the relationships between AFR-PEPA-N's oligomer crystallinity and the properties of phenylethynyl-terminated polyimides. This understanding is valuable in processing AFR-PEPA-N by resin transfer molding (RTM) to obtain its optimum properties. The investigation included the identification of a processing window, temperature overlap between the melting of residual crystals and crosslinking reactions, and liquid crystallinity behavior. These reactions were investigated primarily through birefringence.
The residual crystals were found to be innate in the oligomer powder and not created by preliminary thermal processing. Therefore a reasonable processing window was found based upon the reduction of crystal size by appropriate dissolution techniques. Possible nematic liquid-crystalline characteristics were found to be present at 360oC.
A new imide oligomer, which was based upon AFR-PEPA-N's original structure, was synthesized. The non-linear, flourinated backbone of AFR-PEPA-N was replaced with a co-linear backbone, pyromellitic dianhydride (PMDA). These modifications were made in hopes to improve upon the network structure by it becoming more regular and resistance to nano-sized defects in the final crosslinked structure. The initial characterization found that the new polyimide, AFR-P3, displayed a cure temperature at 350oC. The degree of cure reaches about 80 to 90 percent complete based upon the consumption of the carbon-triple bond. AFR-P3 did not show signs of liquid-crystalline behavior. However, there will be future work in creating a more rigid-rod, self-assembling oligomer that can attain optimum thermal and mechanical properties.
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Polarized Luminescence and Chiroptical Switching Functionalities of Liquid Crystalline and Chiral Conjugated Polymers / 液晶性およびキラル共役系高分子の偏光発光とキラル光学スイッチング機能San Jose, Benedict Arcena 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18297号 / 工博第3889号 / 新制||工||1597(附属図書館) / 31155 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 赤木 和夫, 教授 山子 茂, 教授 秋吉 一成 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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OXYGEN TRANSPORT AS A STRUCTURE PROBE FOR HETEROGENEOUS POLYMERIC SYSTEMSHu, Yushan 08 April 2005 (has links)
No description available.
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有機半導体材料の開発 : 共役系骨格に対する置換基導入の集積性への影響とデバイス応用に向けた物性評価 / ユウキ ハンドウタイ ザイリョウ ノ カイハツ : キョウエキケイ コッカク ニタイスル チカンキ ドウニュウ ノ シュウセキセイ エノ エイキョウ ト デバイス オウヨウ ニ ムケタ ブッセイ ヒョウカ髙木 阿久斗, 高木 阿久斗, Akuto Takagi 22 March 2018 (has links)
博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University
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