含苯并咪唑单元可溶性聚酰亚胺的合成和性能

SYNTHESIS AND PROPERTIES OF SOLUBLE POLYMIDES CONTAINING BENZIMIDAZOLE MOIETY

合成了一种刚性芳香二胺单体3,3',5,5'-四甲基-4,4'-二胺基苯基甲苯(BDAP),与6-氨基苯基-2-氨基苯并咪唑(BIA)组成混合二胺,分别与4种商品化的二酐单体(均苯四酸二酐(PMDA)、联苯四酸二酐(BPDA)、二苯酮四酸二酐(BTDA)和二苯醚四酸二酐(ODPA))一步法缩聚合成了一系列可溶性聚酰亚胺.采用FTIR,1H-NMR,UV-Vis,DMA和TGA等测试方法对所制备的聚酰亚胺进行了表征.结果表明,所制备的聚酰亚胺具有良好的溶解性能,能够在NMP和DMAc等常规溶剂中溶解;耐热性及力学性能优良,玻璃化转变温度超过410℃,分解温度在500℃以上.

A new aromatic diamine monomer, a,a-bis（4-amino-3,5-dimethylphenyl）phenylmethane （BADP） ,was synthesized via a straightforward one-step procedure with high yield. FTIR and I H-NMR were employed to confirm the designed structure. In order to maintain the excellent thermal properties and improve the solubility of polyimides, a series of aromatic polyimides were successfully synthesized via one-step polymerization method in anhydrous N-methyl-2-pyrrolidone （NMP） by a reaction of 2-（ 4-aminophenyl ） -5- aminobenzimidazole （BIA） ,the synthesized BADP and one of four dianhydrides （PDMA, BPDA, BTDA and ODPA）. The structures of copolyimides were confirmed by FTIR, showing the characteristic peaks of polyimides at 1780,1720 and 725 cm-l. The UV-Vis measurements indicated that the cut-off wavelengths were at 360 380 nm without consideration of relatively weak transmittance in the range of 310 -360 nm. As we expected, the polyimides exhibit excellent solubility, and can be dissolved in normal solvents such as NMP, DMAc or CHCI3. The soluble polyimides show a relatively higher glass transition temperature （ Tg 〉 410℃ ） measured by dynamic mechanical analysis （DMA） and a high initial decomposition temperature （Ta 〉 500℃ ） in TGA and more than 55 wt% residues at 900℃ under nitrogen atmosphere. Moreover, the tensile strength of polyimides is 61 - 100 MPa. The soluble polymers can be used as high performance resins or processed into high performance fibers.