Preparation And Characterizaion Of Epoxy Resin Composites With Structural And Absorbing Properties Combined

Integration of structure and function has been a common direction for thedevelopment of material science and technology. Furthermore, it is an inevitable trendof novel aerospace materials. In order to obtain the materials with structural andabsorbing properties combined, the epoxy resin matrix composites, withferrocenyl-terminated hyperbranched polyesters (HBPE-Fc)、BaFe12O19aerogels、Fe3O4aerogels and graphene/Fe3O4(GA/Fe3O4) composite aerogels asmicrowave-absorbers, were incorporated into the matix of epoxy resin (EP) modifiedwith epoxidized hyperbranched polyesters (EHBP) respectively, by means of solutionblending. The content and conclusion of this thesis are as follows:(1) The first to the fourth generation (G1-G4) of HBPE-Fc with topologiesstructures were successfully synthesized by esterification. HBPE-Fc/EHBP/EPcomposites were prepared by combing the as-prepared HBPE-Fc with the matix ofepoxy resin modified with EHBP, and their mechanical and microwave absorptionproperties were studied. The results indicated that HBPE-Fc/EHBP/EP compositesachieved relatively good mechanical properties with low content of HBPE-Fc. Thetensile strength, tensile rupture elongation and impact strength maximum increased by21.81%,34.49%, and37.80%, respectively, compared with pure EP. Furthermore，the composites possessed good thermal and microwave absorption properties,reaching up to a reflectivity of-13.33dB throughout the range of8~18GHz.(2) BaFe12O19aerogels with mesoporous structures were fabricated via a sol-gelprocess. BaFe12O19aerogels/EHBP/EP composites with low density were obtained bymixing the as-prepared BaFe12O19aerogels with the matix of epoxy resin modifiedwith EHBP, and their mechanical and microwave absorption properties were studied.The results indicated that lower content of KH550modified BaFe12O19resulted ingood mechanical properties, the tensile strength, elongation at break and impactstrength maximum increased by19.68%、28.22%and55.80%, respectively,compared with pure EP. Furthermore，the composites possessed good thermal andmicrowave absorption properties, their reflectivity were among-9.2~-18.0dB throughout the range of8~18GHz.(3) Fe3O4aerogels were prepared by a sol-gel method. Fe3O4aerogels/EHBP/EPcomposites with low density were obtained by mixing the as-prepared Fe3O4aerogelswith the matix of epoxy resin modified by EHBP, and their mechanical andmicrowave absorption properties were studied. The results indicated that lowercontent of KH550modified Fe3O4aerogels possessed good mechanical performance,and the tensile strength, elongation at break and impact strength maximum increasedby21.81%,34.49%, and15.75%, respectively, compared with pure EP. Furthermore，the composites possessed good thermal and microwave absorption properties, theirreflectivity reached up to a reflectivity of-16.67dB throughout the range of8~18GHz.(4) GA/Fe3O4composite aerogels, prepared via a wet chemical self-assemblyprocess, were incorporation into epoxy resin modified with EHBP to getGA/Fe3O4/EHBP/EP composites, which had low density. Their mechanical andmicrowave absorption properties were studied. The results indicated that lowercontent of GA/Fe3O4composite aerogels could keep the good mechanical propertiesof epoxy resin, and the maximum tensile strength, elongation at break and impactstrength was60.98MPa、6.09%and18.43kJ·m-2, respectively. Furthermore，thecomposites possessed good thermal and microwave absorption properties, theirreflectivity were among-10.65~-16.52dB throughout the range of8~18GHz.(5) HBPE-Fc、BaFe12O19aerogels、Fe3O4aerogels and GA/Fe3O4compositeaerogels were incorporated into epoxy resin matrix modified by EHBP respectively,and the composite systems were combined with carbon fiber to get the correspondingcomposites by mould pressing. The composites showed good mechanical properties,tensile strength of the composite contained Fe3O4aerogels increased by36.27%compared with pristine epoxy/carbon fiber. And the impact strength of the compositecontained BaFe12O19aerogels increased by126.7%compared with pristineepoxy/carbon fiber composite. At the same time, the composites possessed goodabsorbing performances, the reflectivities of all the as-prepared composites werebelow-10dB in the range of8~18GHz, while the composite contained BaFe12O19aerogels could reach to-21.26dB.