| Geopolymer?GP?is a three-dimensional amorphous aluminosilicate inorganic polymer which can be synthesized through chemical excitation from aluminosilicate minerals and solid industrial wastes.Geopolymer has been investigated extensively since its considerable merits,such as:low cost,simple process,low energy consumption,low pollution,high resistance temperature,excellent corrosion resistance,outstanding durability,good mechanical properties and so on.In this article,high-property geopolymer composite material was synthesized combining the ultrafine kaolin and carbon nanotubes.Moreover,the microstructure,electrical properties and mechanical properties of the material were investigated thoroughly.?1?The carbon nanotubes/geopolymer composites?CNTs/GP?was successfully prepared by adding acidified multi-walled carbon nanotubes?o-MWNTs?as reinforcing materials.The microstructure shows that there is a small amount of warped carbon nanotubes in the geopolymer matrix.The compressive strength of the CNTs/GP decreased comparing with the pure geopolymer.When 1wt.%of CNTs/GP is added,the compressive strength of the composite is 31.4 MPa,which decrease by 13.25%.However,the electrical conductivity of the geopolymer composites has been enhanced effectively with the increasing amount of CNTs.These results imply that even acidified carbon nanotubes disperse better in water,their dispersion in the geopolymer matrix is poor,and the pores at the interface of CNTs and geopolymers are the source of stress concentration,which result in lower resistance of the geopolymer.?2?In order to further improve the comprehensive property of geopolymers,The ternary composite of CNTs/AgNWs/GP composites were prepared by adding acidified multi-walled carbon nanotubes and silver nanowires?AgNWs?into the polymer precursor.The have improvement in the compressive strength of the geopolymer,The results demonstrated that the compressive strength of the geopolymer evidently improved with the conjunction of the two kinds of hybrid fiber?CNTs and AgNWs?.The compressive strength of the geopolymer arrived 50.91 MPa with 1wt.%CNTs/1wt.%AgNWs,which increased by 40.6%.?3?Silica-coated multi-walled carbon nanotubes?SiO2-MWNTs?is a kind of hybrid materials,which can be applied as a reinforcing material prepared by sol-gel method.SiO2-MWNTs/GP composites were synthesized through mixing the SiO2-MWNTs with metakaolin,and water glass and hydroxide were used as sodium alkali activators.Infrared spectroscopy?FIIR?,scanning electron microscopy?SEM?,X-ray diffraction?XRD?were performed to study the material's construction.In order to evaluate the effect of reinforcing materials on the microstructure and properties of geopolymers,?TGA-DSC?,electrical conductivity,compressive strength were characterized.The results demonstrated that the addition of reinforcing material has positive effect on the compressive strength of the geopolymer.When 0.5 wt.%SiO2-MWNTs is added,the compressive strength of the geopolymer is 59.5 MPa,which increases by 65%compared with pure geopolymer.Meanwhile,the electrical conductivity of geopolymer composites increases with the increasing amount of SiO2-MWNTs.When the amount of SiO2-MWNTs reaches 20%,the conductivity reaches 20.09×10-66 S/cm,which is an order of magnitude higher than a lower-level additive. |
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