Synthesis and properties of novel polyamides through polymer reactions.
| Autor: | Hui-Chen Lee, 李蕙珍 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 In this study, a series of novel polyamides having pendant maleimide groups were synthesized by direct polycondensation of 5-male- imido-isophthalic acid with 4,4'-(Hexafluoroisopropylidene) dianiline and 4,4'-Dicarboxydiphenyl ether. All the aromatic polyamides were readily soluble in various polar aprotic solvents such as N, N-dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP) and tetrahydrofuran (THF). One of the major drawbacks of this maleimide–containing polyamide is their brittleness. To overcome this disadvantage, Polyamides modified with Polytetrahydrofuran bis- (3-aminopropyl) terminated (P-THF) cross-linked structure were obtained through Michael addition reaction. The modified polyamides exhibited 60% with elongation at break. Moreover, these films were thermally treated at 250℃ to decompose P-THF domains and generated pores in polyamide film. The presence of pores were confirmed by SEM and TEM. With the incorporation of air nanopores, the dielectric constants were found to decrease 9~23% comparing with original polyamide film. Organic-inorganic hybrid materials were also obtained from covalently incorporation combining nanoporous POSS molecules to polyamide. The thermal stability was measured with TGA in air. At 800℃, the film which contained the most POSS content showed the highest char yields. Some POSS might have degraded and evolved out from the matrix under heat. The morphologies of PA-POSS nanocomposites were observed by AFM, SEM and TEM. POSS molecules tethered to polyamide form self-assembled architecture as the mole ratio of POSS is increased. The dielectric constants of PA-POSS were lower due to the increased free volume and the chain interaction. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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