Study On The Mechanical Properties And Electromagnetic Shielding Properties Of Latex-reinforced Graphene-based Aerogels And Their Composite

Graphene oxide aerogel（GOA）has high specific surface area,large pore volume and low density.GOA has a wide range of applications in aerospace,electromagnetic shielding,super capacitors,energy storage batteries,adsorption materials and many other fields.However,GOA only relies onπ-πbond and has mechanical property problems,such as easy breakage,easy collapse and low strength,which limits its application.GOA has three-dimensional pore structure.After reduction,in could be used as an electromagnetic shielding material to increase the incident path of electromagnetic wave and effectively improve the electromagnetic shielding performance.Therefore,in this study,two schemes were selected to enhance the mechanical properties of aerogel.One was to prepare composite aerogel by adding polymer into the GO suspension.The other was to graft GO and carbon nanotube（CNT）to improve the mechanical properties of aerogel.The electromagnetic shielding effect of the composite was further improved by adding magnetic nanoparticles with the enhanced aerogel as the skeleton of the composite.In this paper,styrene butadiene latex（LSBR）was introduced as the enhancer to construct the cross-linking structure and enhance the mechanical properties of GO/CNT aerogel,and the optimal process flow and ratio were determined.On this basis,polyethylenimide（PEI）was grafted on the surface of GO and CNT,the interface compatibility of GO,CNT and LSBR was improved and the mechanical properties of aerogel were improved through the synergistic effect of latex and PEI.Meanwhile,the graft of PEI also gave the aerogel certain adsorption properties.In order to improve the electromagnetic shielding effect of aerogel and its composites,Fe₃O₄nanoparticles were synthesized in situ in aerogel,and the effects of GO content and the ratio of GO and CNT on the electromagnetic shielding performance were investigated.The main research contents are as follows:（1）GO/CNT/SBR aerogel was prepared by self-assembly,freeze-drying and hot vulcanization of GO,CNT and LSBR.When the mass ratio of GO to CNT is 7:3 and the mass ratio of LSBR to GO is 2:1,GO/CNT/SBR aerogel has better mechanical properties and thermal stability,and its maximum stress ratio is increased by 784%.（2）PEI was grafted on the surface of GO and CNT,and a series of GO/CNT/SBR aerogels were prepared by self-assembly,freeze-drying and hot vulcanization processes:the aerogels were grafted on the surface of GO and CNT respectively,and the aerogels were grafted on both GO and CNT.Compared with the aerogel without PEI grafting,the maximum stress of the aerogel grafted with PEI on CNT increased by 6%,that of the aerogel grafted with PEI on GO increased by 20%,and that of the aerogel grafted with PEI on both GO and CNT increased by 29%.This confirmed that the graft of PEI on GO and CNT improved the mechanical properties of aerogel,and the graft of PEI on GO was more significant than that on CNT.PEI grafting also improved the adsorption performance of aerogel.The adsorption quality of methyl orange solution by GO-PEI/CNT/SBR aerogel increased by 348%,and the adsorption quality of GO/CNT-PEI/SBR aerogel increased by 67%.The adsorption quality of GO-PEI/CNT-PEI/SBR aerogel was increased by 393%.（3）GO,CNT and Fe₃O₄nanoparticles were reduced by hydrazine hydrate and self-assembled into rGO/CNT/Fe₃O₄/SBR hydrogels,which were dried into aerogels and then hot-pressed and vulcanized to prepare polymer composites.The electromagnetic shielding performance of rGO/CNT/Fe₃O₄/SBR composites is the highest,with a maximum value of 29.41 dB,when the mass ratio is GO:LSBR=6:166 and GO:CNT=7:3.