The Preparation And Research On Surface Modification Of Polyimide Fiber With Graphene Oxide And Its Application For Mechnical Enhancement Of Geopolymer

As a new kind of organic fiber with the properties of high strength,high modulus,heat-and-cold resistance,radiation resistance and electrical properties,polyimide(PI)fiber can be used in the field of aerospace,cement,chemical industry,fire-fighting and other fields,and it shows an excellent application value.Although geopolymer has the advantages of durability,high strength,chemical resistance,low emissions,less energy consumption,the brittleness property limits its applications in many fields.Geopolymer enhanced by modified fiber are widely investigated by researchers.In this subject,polyimide fiber was modified by graphene oxide to improve its surface roughness,so that the interfacial properties of the fiber and the mechanical properties of the geopolymer composites were increased.With the measurement of SEM,FTIR,XPS,we can find that graphene oxide was successfully grafted onto the surface of polyimide fiber.The fly ash-based geopolymer with different content of alkali-activator was prepared,by analyzing morphology and mechanical properties of geopolymer,the optimal mechanical property can be obtained with content of 30 wt%.Then the pristine and decorated PI fibers with different mass fraction were mixed with geopolymer.The mechanical properties were measured and the morphology was observed.Results show that composites with pristine and decorated PI fibers both exhibit an optimum compressive strength and flexural strength with the fiber content of 1.2 wt%.Compared to the unreinforced geopolymer,the geopolymer composites obtained an satisfied improvement by approximate 59%in compressive strength and 200%in flexural strength.Compared to the geopolymer composites without GO-decorated fiber,the composites earned an satisfied improvement by nearly 86%in compressive strength and 290%in flexural strength.The research and literature summary can show that fibers can disperse and dissipate fracture energy through the act of bridging,breaking,pulling and stripping so as to enhance the geopolymer.