| The composite materials of carbon fiber and resin formed has advantaged of high strength, low density and so on, has becomes the excellent advanced aerospace materials. This year, the research of Terahertz Science has made great progress in many fields. As one of the developing directions of the future high precision, stealth and anti stealth radar, the terahertz wave absorbing materials will have a broad application prospect in the military.This paper combined with the results of the gelatin time and DSC of different heating rates, the curing process of the resin is 80?/2h+130?/4h+180?/3h, then mixed resin with the short carbon fiber, used the hydroxypropyl methyl cellulose (HPMC) as dispersing agent of carbon fiber, researched the effect of composite mechanical properties and heat resistance by dispersing agent, and studied the dispersion principle, the results showed that the HPMC can effectively improve the mechanical properties of composite materials when content is 0.13%, improves the tensile strength of 47.5% composites, impact strength 62.7%, reduced the agglomeration of carbon fiber. The effects of length and content on the mechanical properties were studied. The results showed that:when carbon fiber length is 2 mm and content is 0.30%, it had good mechanical properties of the composite materials, the tensile strength, flexural strength, flexural modulus drink impact toughness were compared with pure resin increased 39.1%,12.9%,12.5% and 61.1%, respectively.Based on the length?content and the dispersant of short carbon fiber, treatment of carbon fibers'surface by air and nitric acid oxidation, studied the effect of air oxidation temperature and nitric acid oxidation time on composite materials, and compared the two oxidation methods, the results showed that the oxidation temperature is 450? centigrade change the mechanical properties of the composites, the tensile strength increased by 7.45%, the flexural strength increased 13.03% and the flexural modulus increased by 7.98%, impact toughness increased by 13.10%; by nitric acid oxidation time is 60min, change the mechanical properties of the composites, the tensile strength increased by 9.11%, the flexural strength increased 19.19% and the flexural modulus increased 12.92%, the impact toughness increased by 15.23%; by nitric acid oxidation of 60min were compared with the air oxidation of 450? increased, and the DMA results showed that nitric acid oxidation time is 60min treatment, the Tg of the composite is increased by about 8?, loss peak decreased, heat resistance and interface of the composite are better.Finally, the prepared nano-particles by sol-gel method, tested the absorption coefficient of different systems in the 0.5-2.5THz, the results showed that TiO2, Fe-TiO2 and BaTiO3 nanoparticles could improve the scratch of short carbon fiber/epoxy resin composites in the absorbing properties of the THz band, TiO2/CF/E-51 reached the maximum absorption system a value is 57.5 at 0.78THz, second peaks appeared at 1.86THz; Fe-TiO2/CF/E-51 and Fe-TiO2/BaTiO3/CF/E-51 system have reached the maximum values were 54.4 and 78.1 at 1.12THz, and reduced to a minimum at 1.8THz, the BaTiO3/CF/E-51 system has a gentle absorption peak at 1.26THz; Fe3+ can be formed ferrite composite materials in the compositions, enhanced the absorbing properties of composites. |
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