以4,4'-对苯二甲酰二邻苯二甲酸酐(TDPA)和1,3-双(4-氨基苯氧基)苯(BAPB)为单体,采用2步溶液缩聚法,制得高相对分子质量的聚酰胺酸(PAA)溶液,经4种亚胺化工艺合成了TDPA/BAPB型聚酰亚胺(PI)树脂.通过FT-IR、WAXD、DSC、TGA、溶解性能等对PI树脂进行测试和表征.FT-IR表明4种方法均形成了酰亚胺结构,WAXD及DSC分析表明TDPA/BAPB型PI为部分结晶型结构,熔融温度(Tm)为363~370℃,TGA测试揭示乙酸酐/吡啶化学亚胺化PI耐热性能最佳,且较其它3种方法溶解性也更好,可溶于DMSO、NMP、间甲酚等强极性溶剂中.PAA溶液流延成膜性能良好,热亚胺化PI薄膜具有较好的力学性能,拉伸强度为118.3 MPa,弹性模量为2.5 GPa.
A novel diketone anhydride polyimide( PI) was synthesized from 4,4'-terephthaloyldiphthalic anhydride( TDPA) and 1,3-bis( 4-aminophenoxy) benzene( BAPB) by two-step polycondensation. Polyamic acids( PAAs)of high molecular weight were obtained,and PIs were synthesized from PAAs by four different imide methods. The structures and physical properties of PIs were characterized by FTIR,DSC,TGA,WAXD,an universal testing machin for stress-strain behaviour. Each method can make PAA transform into PI,in DSC and WAXD the TDPA /BAPB PIs appeared partly crystallized and melted at 363 ~ 370 ℃. In TGA the PI by imidization from acetic anhydride and pyridine showed the best thermostability,its solubility were better than other three PIs that was soluble in polar organic solvents as dimehtylsulfoxide( DMSO),N-methyl-2-pyrrolidone( NMP),m-cresol,et al. The PAA could be processed into good quality film,the PI film possessed excellent mechanical property,a high tensile strength( 118. 3 MPa) and modulus( 2. 5 GPa).