含酞Cardo结构聚芳醚酰亚胺树脂及其复合材料的设计合成与性能

Synthesis and properties of reactive polyetherimide oligomer containing cardo side groups and its composites

以邻甲酚酞和对氯硝基苯为初始原料,经过亲核取代反应、硝基还原反应合成一种含酚酞结构的芳香二元胺(MPDA);MPDA再与双酚A型二醚二酐(BPADA)进行缩合反应,采用马来酸酐(MA)进行封端;最后,经环化脱水反应,制得马来酰亚胺封端的含酞Cardo结构聚醚酰亚胺齐聚物(mPEI-C)。利用FTIR、~1H-NMR、DSC、TGA及DMA等分析测试手段,表征了mPEI-C的化学结构、固化行为、耐热性能及其固化薄膜在不同温度下的力学性能。采用湿法预浸-模压法,制备T700炭纤维增强mPEI-C树脂基复合材料,测试表征了复合材料的力学性能,研究探讨了复合材料的破坏机制。研究结果表明,mPEI-C为无定型的低分子量齐聚物,具有优异的溶解性能和耐热性能,玻璃化转变温度达320℃以上,初始热分解温度接近430℃,室温下固化薄膜拉伸强度达130 MPa;其炭纤维复合材料的层间剪切强度和弯曲强度也分别达到了86.2、1481.6 MPa,且表现出良好的耐湿热能力。

Maleimide-terminated polyetherimide oligomer containing cardo side groups（ mPEI-C） was synthesized from the diamine compound derived from the o-cresolphthaleine,and a dianhydride 4,4 ＇-（ 4,4 ＇-Isopropylidene-diphenoxy） bis（ phthalic-anhydride）,with maleic anhydride as end-capping reagent. The chemical structures of the oligomer and their intermediate compounds were characterized by means of Fourier transform infrared（ FTIR） spectrometer,nuclear magnetic resonance spectrometer（^1 HNMR） and gel permeation chromatography（ GPC）. The oligomer is soluble in common organic polar solvents and its molecular weight is ～ 2386 g/mol. The thermal properties of the oligomer and its cured resins were investigated by differential scanning calorimeter（ DSC）,thermal gravimetric analyzer（ TGA） and dynamic mechanical analyzer（ DMA）. The DSC curve showed that the oligomer began to soften at ～ 260 ℃ and subsequently to cure at the temperature range of 275 ～ 360 ℃. The DMA and TGA results showed that the glass transition temperature and initial thermal decomposition temperature reached 323 ℃ and 430 ℃,respectively,where the residual weight at 700 ℃ was 63.9%.The tensile properties of mPEI-C cured film were measured at different temperature.The excelled mechanical properties and good retention at elevated temperatures were observed. The tensile strength values at 30,100,150,200,250 and 300 ℃ are 130.5,99.2,72.3,56.3,32.2 and 5.1 MPa,respectively.T700/mPEI-C composites were prepared by solution-prepared prepreg and hot-pressing methods,and no internal defects were seen when they were scanned using ultrasonic technology. Their interlaminar shear strength（ ILSS） and flexural strength at dry/wet states reached 86.2 MPa/80.4 MPa and 1481.6 MPa/1343.2 MPa.Fracture surface morphology of mPEI-C/T700 composites after ILSS tests exhibited that good adhesion between fiber and matrix