| Summary: | 博士 === 國立臺灣科技大學 === 化學工程系 === 88 === ABSTRACT
A variety of diamines with various structural modifications such as flexible bridging linkages, bulky substituents, noncoplanar biphenylene units, and bulky pendent groups have been synthesized and used to prepare various new soluble and processable polyamides and polyimides. The incorporation of flexible units, such as aryl ether, hexafluoroisopropylidene, sulfonyl, isopropylidene, oxyethylene and diphenylmethylene units and bulky tert-butyl substituents, and noncoplanar 2,2''-dimethyl-4,4''-biphenyl, as well as of pendent groups such as cyclododecylidene, adamantane, tricyclodecane, norbornane, tert-butylcyclohexane and phenylcyclohexane groups into the polymer backbone of polyamides and polyimides lowered the crystallinity and enhanced the solubility of these polymers. Most of these polyamides and polyimides were soluble in various solvents including N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, cyclohexanone, and also in tetrahydrofuran. These polymer films were obtained by solution-casting and showed tough and flexible behavior. All of these polyamides and polyimides exhibited good thermal stability and mechanical properties. These polymers had glass transition temperatures higher than 250 ℃ and 10 % weight loss temperatures higher than 450 ℃. Most of these polymer films exhibited tensile strength above 80 MPa and tensile modulus above 2.0 GPa. The effects of various structures on the polymer properties such as solubility and thermal stability were investigated. In comparison with the effect of various structural modifications on the polymer properties, the incorporation of rigid and bulky pendent groups such as adamantane as well as diphenylmethylene units led to the most success. The introduction of sulfonyl and oxyethylene units in the polymer backbone showed relatively less satisfactory results.
A series of new polyaspartimides resulted from the Michael addition reaction of bismaleimide BEMM and various diamines were successfully prepared herein. These polyaspartimides exhibited amorphous behavior and excellent solubility. The polymers had high Tg values and good thermal stability. Thus these materials could be considered as new processable polymeric materials.
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