含噁唑环聚酰亚胺的制备及性能

Synthesis and Properties of Novel Polyimides Containing 2,6-Benzobisoxazole Units

以刚性棒状结构的2,6-二(对氨基苯)苯并[1,2-d;5,4-d’]二口恶唑为单体,采用两步法与三种不同结构的酸酐合成出了新型含口恶唑环聚酰亚胺薄膜。对聚酰亚胺的预聚体——聚酰胺酸的制备工艺的影响因素进行了详细的研究,聚酰胺酸的特性黏度均达到1.0dL/g以上,通过热环化处理得到了分子量较高的聚酰亚胺薄膜。经红外光谱测定,聚酰胺酸完全转化成聚酰亚胺。薄膜玻璃化温度均高于280℃,空气中热失重温度在520℃以上,表现出优异的热稳定性。

A series of aromatic polyimides based on 2,6-bis（p-aminophenyl）-benzo[1,2-d;5,4-d’]bisoxazole were synthesized in order to improve the thermal stability via a conventional two-stage procedure with a variety of dianhydrides. The reacting conditions of the intermediate poly（amic-acid）s were studied in detail. The poly（amic-acid）s had inherent viscosities over 1.0dL/g and could be thermally converted into lightly yellow films. The IR spectra were used to identify the imidization of poly（amic acid）s to polyimides. The glass transition temperatures （Tg） of polyimides were over 280 ℃,and the 5% mass-loss temperatures were over 520 ℃ in air,which showed excellent thermal stability.