Research On The Mechanical Properties Of Multi-walled Carbon Tube Coated With Single-walled Carbon Tube Fiber

Nanotubes have received extensive attention because of their many excellent properties.At the same time,the research of carbon nanotube macroscopic assembly has promoted the application of carbon nanotubes in practice.This paper proposes a macro-structure in which a single-walled carbon tube fiber and a multi-walled carbon tube are assembled into a coaxial structure.First,the controllable preparation method of multi-walled carbon tube material coated with single-walled carbon tube fiber was studied,and its mechanical properties were studied and analyzed.Then it was compounded with polydimethylsiloxane(PDMS)to obtain flexible Single-walled carbon tube fibers are coated with multi-walled carbon tube/PDMS composite materials,and their mechanical and electrical properties are explored,which provides a certain reference value for the research of carbon nanotube composite materials.In this thesis,ferrocene and xylene are used as catalysts and carbon sources,respectively,and single-wall carbon tube films are prepared by chemical vapor deposition,and single-wall carbon tube fibers are obtained by spinning.Then,using ferrocene and dichlorobenzene as catalysts and carbon sources,and using single-wall carbon nanotube fibers as the substrate,multi-wall carbon tubes are grown on the single-wall carbon tube fibers by chemical vapor deposition.The multi-walled carbon tube fiber coated with multi-walled carbon tube material has a cylindrical shape with a length of 11.5cm and a diameter of up to 5.5mm.The surface is similar to a sponge and has good elasticity;the microstructure is entirely composed of carbon nanotubes It is composed of overlapping each other,in which the multi-walled carbon nanotube sponge has a large number of pores.By changing the process parameters,the growth rate,growth diameter and microscopicity of the multi-walled carbon nanotube spongecoated single-walled carbon nanotube fiber material can be achieved Structure control.The mechanical properties of single-walled carbon tube fibers coated with multiwalled carbon tube materials were studied.In the stretched state,the maximum breaking stress of the multi-walled carbon tube material coated on the single-walled carbon tube fiber is 270 MPa,which is equivalent to the maximum breaking stress of the internal single-walled carbon nanotube fiber,indicating that the single-walled carbon tube fiber is coated The force experienced by the multi-walled carbon tube material under tension is mainly provided by its internal fibers.It can be seen from the fracture section of the material that the internal fiber has a certain connection with the external sponge.The design pull-out test explores the interface between the internal fiber and the external sponge after the single-walled carbon tube fiber coated with the multi-walled carbon tube material is broken.The multi-walled tube covered by the surface of the force and the drawn fiber proves that the single-walled carbon fiber and the external multi-walled carbon tube have a good interface.The mechanical and electrical properties of single-walled carbon tube fibers coated with multi-walled carbon tube/PDMS composites were studied.Using the porosity of the multi-wall carbon tube material coated on the single-wall carbon tube fiber,PDMS can be directly poured into the sample to obtain a uniform nano-composite material.The tensile test of the composite material showed that the tensile strain at break of the composite was 120%,which was similar to the tensile strain at break of the pure PDMS sample,indicating that PDMS played a major role in the tensile test of the composite material.At the same time,the electrical properties of the multi-walled carbon tube/PDMS composite coated on the single-walled carbon tube fiber are investigated.The tensile cycle test is carried out under a certain strain range.The resistance changes regularly with the tensile stress and can be used as stress Strain sensor.