Synthesis and Rapid Polymerizations of Aryl- and Alkyl-bis(azetidine-2,4-dione)s to Polymalonamide Elastomers

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• 作者：Ming-Chieh Kuo ; Yen-Chen Tung ; Chung-Lun Yeh ; Hsin-Yu Chang ; Ru-Jong Jeng ; Shenghong A. Dai
• 刊名：Macromolecules
• 出版年：2008
• 出版时间：December 23, 2008
• 年：2008
• 卷：41
• 期：24
• 页码：9637-9642
• 全文大小：132K
• 年卷期：v.41,no.24(December 23, 2008)
• ISSN：1520-5835

文摘

Two new synthetic methodologies for making aryl- and alkyl-bis(azetidine-2,4-dione)s have been accomplished in this study. A new family of N,N′-benzophenonyl bis(azetidine-2,4-dione)s (2) has been successfully synthesized through autoxidation of readily available diphenylmethane bis(azetidine2,4-dione)s (1) in 70−80% yields. In addition, the synthesis of N,N′-alkylene bis(azetidine-2,4-dione)s (3) was accomplished through sensitized photocyclization of N,N′-alkylene bis(N-formyl-2-methylacrylamide)s in a new three-step process from alkylene diamines in overall yields of 63−80%. The prepared bis(azetidine-2,4-dione)s were converted to polymalonamide elastomers in two steps by reacting first with a long-chained polyether diamine of 2000 g·mol⁻¹ molecular weight to form the prepolymers. Subsequently, the prepolymers were melt-polymerized with hexamethylene diamine to produce the final elastomeric polymalonamides. The present study further investigated the reactivities of these aryl- and alkyl-bis(azetidine-2,4-dione)s as well as their elastomeric property differences due to structural variations. The study found that the order of the intermediate’s reactivity toward amines is (2) > (1) > (3). This implies that aryl azetidine-2,4-diones, (1) and (2), are more reactive than their aliphatic counterpart (3) toward amines in their ring-opening reactions. Furthermore, the ketone-conjugated aromatic intermediates (2) were found to produce the highest molecular weight polymalonamides in short reaction time and result in polymalonamides with overall superior mechanical properties. For the final elastomeric polymalonamides produced, we found that aromatic polymalonamides were mostly amorphous, but aliphatic elastomeric polymalonamides were fibrous semicrystalline. All of the polymalonamides based on aryl bis(azetidine-2,4-dione)s possess temperature-resistant properties of >350 °C. The study indicated that the carbonyl activated bis(azetidine-2,4-dione)s, such as (2), can serve as the best candidate intermediates for making elastomeric polyamides via the rapid reaction injection molding (RIM) process similar to those practiced in polyurethanes.