Effect Of Thermal Cycling And Electron Irradiation On Structure And Properties Of M55J/ce Composites

High-modulus carbon fiber/cyanate composites as satellite integrated supports have long-life and dimensional thermal stability performance requirements,while satellites are affected by charged particle irradiation and high and low temperature environments when they are in orbit.The deflation,microcracking,degradation,etc.produced by the underlying material will have a significant impact on the dimensional stability of the satellite structural members.In this paper,M55J/cyanate composites were studied.After undergoing thermal cycling and electron irradiation,the thermal expansion coefficient and layer shear strength were studied.Electron scanning,electron paramagnetic resonance and Fourier infrared spectroscopy were used.The morphology,free radicals and evolution of functional groups were analyzed and summarized to reveal the single-factor effects of electron irradiation and thermal cycling on composites and the effects of two-factor interaction.The results show that electron irradiation has no significant effect on the thermal expansion coefficient and layer shear strength of the composite.Under the thermal cycle,the thermal expansion coefficient of the composites did not change significantly,and the layer shear strength showed a significant downward trend.Under the action of electron irradiation and thermal cycling,the thermal expansion coefficient of 0 degree unidirectional material of M55J/cyanate ester did not change significantly,while the thermal expansion coefficient of 90 degree unidirectional material showed a downward trend,the decreasing trend of material layer shear strength and thermal cycle The trend when acting alone is more consistent.Comparing the effects of single factors of electron irradiation or thermal cycling with the effects of two-factor interaction,it can be found that the two-factor effect is greater than the single-factor effect but less than the single-factor effect.Under 1MeV electron irradiation,the composite material is debonded,the free radicals increase,and the oxygen and nitrogen elements are seriously lost,thus causing the fluctuation of the macroscopic properties of the composite material.Under the action of high-order thermal cycle,the internal carbon fiber generates stress,the debonding phenomenon is obvious,and the matrix generates N-H new bond,thus causing a significant decrease in the layer shear strength.Under the action of 1MeV electron irradiation and 54750 thermal cycles,the debonding phenomenon of the micro-morphology of M55J/cyanate composite is more serious,which aggravates the separation of carbon fiber and cyanate,and produces a large material.Stress;the free radical content of the composite material is relatively reduced,and the interaction between the two promotes the free radical reaction,sothat the free radicals tend to decrease;the formation of new NH bonds by infrared spectroscopy,functional groups such as fatty ethers,carbon-carbon skeletons and triazine rings The content is increased;the storage modulus of the material is reduced by 50%,the loss modulus is decreased by 62%,the glass transition temperature is shifted to the high temperature direction,and the crosslink density is decreased,so that the influence on the macroscopic properties of the material is more obvious.