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Polyvinylidene fluoride (PVDF) film is a kind of material with low density,flexibility, plasticity, chemical resistance, high temperature resistance, radiationresistance and dielectric property. Its excellent performance can improve the storageperformance and the burden limit of the spacecraft, but also optimize thecomponent design. However, the irradiation and other harsh conditions in the spaceenvironment greatly damage the PVDF film, severely limiting the performance andlife of the components. Therefore, it is very necessary to modify PVDF film, and toexplore the law of modification and the impact of electron irradiation on the PVDFfilm.In this paper, we modified the PVDF film through heat treatment and hotstretching, but also irradiated several types of PVDF film through the electronirradiation. The initial sample and post-treatment samples were characterized usingDSC, infrared spectroscopy, XRD, Agilent impedance analyzer. Finally, accordingto test results, we established fine process parameters of modification, and carriedout a comprehensive analysis and causes exploration about the impact of heattreatment, hot stretching and electron irradiation on the PVDF film.Through testing and analysis, we obtained several results: the heat treatmentprocess with the highest dielectric constant is under the parameters of “quick-cooling,180oC,6h”, the dielectric constant is11.142. The degree of crystallinity,the beta phase content, the dielectric constant and dielectric loss first increase andthen decrease with the increase of the heat treatment time. Below the melting point,the degree of crystallinity, the beta phase content, the dielectric constant anddielectric loss increase with the increase of the heat treatment temperature, andthere is no significant impact on the structure and performance with the change ofthe cooling rate. Above the melting point, quick-cooling leads to the decrease of thecrystallinity and the increase of the β phase, slow-cooling leads to the increase ofthe crystallinity and the increase of the phase. Quick-cooling contributes to theimprovement of the dielectric constant more than slow-cooling. The hot stretchingprocess with the highest dielectric constant is under the parameters of “50mm/min,80oC, stretching factor4”, the dielectric constant is12.077. The beta phase content, the dielectric constant and dielectric loss first increase and then decrease with theincrease of the hot stretching temperature, reaching the maximum at80oC. With theincrease of the hot stretching rate, Iβ/I first increases and then tends to be around aconstant, the degree of crystallinity decreases, the dielectric constant and dielectricloss first increase and then decrease, reaching the maximum at50mm/min. With theincrease of the hot stretching ratio, Iβ/I, the degree of crystallinity, the dielectricconstant and dielectric loss first increase and then decrease, reaching the maximumat factor4. After the electron irradiation, the degree of crystallinity, the beta phasecontent and the dielectric constant decrease, and reduced gradually with theincrease of the irradiation dose. At low frequencies, the dielectric loss does notchange significantly. At high frequencies, the dielectric loss decreases significantly,and reduced gradually with the increase of the irradiation dose. The modified filmsreveal increased resistance to irradiation.The test results indicate that the modification of PVDF film by heat treatmentand hot stretching is feasible, but also electron irradiation leads to obvious effectson the film. These work can be a foundation for further study of the PVDF film.
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