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Date of Publication:2022-10-10

Journal:固体火箭技术

Volume:41

Issue:2

Page Number:226-232,238

ISSN No.:1006-2793

Abstract:Maleimide-terminated polyetherimide oligomer containing cardo side groups(mPEI-C)was synthesized from the di-amine compound derived from the o-cresolphthaleine, and a dianhydride 4,4'-(4,4'-Isopropylidene-diphenoxy)bis(phthalic-an-hydride),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(1H-NMR)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 calo-rimeter(DSC),thermal gravimetric analyzer(TGA)and dynamic mechanical analyzer(DMA). The DSC curve showed that the ol-igomer 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 pre-pared by solution-prepared prepreg and hot-pressing methods,and no internal defects were seen when they were scanned using ul-trasonic 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 adhe-sion between fiber and matrix

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