Preparation And Properties Of Ultrasound-assisted Reinforced Thermoplastics/buckypaper Composites

As carbon nanomaterials,carbon nanotubes(CNTs)maintain excellent properties,such as high strength,high modulus,high conductivity,high thermal conductivity and so on.Carbon nanotubes are usually used to reinforce polymers.With the increasing concentration of CNT,the phenomenon of reunion in matrix became very serious,which affects the mechanical properties of composites.The content of CNTs in the composites can not be more than 10% in melting,solution blending and chemical in situ polymerization.Carbon nanotube paper / polymer composites can improve the content of carbon nanotubes without aggregation of carbon nanotubes.But carbon nanoscale paper has a tight structure,high porosity and small pore size.Traditionally,high-pressure immersion is no longer suitable for thermoplastic materials.To deal with these problems,two kinds of impregnation technology of solution and melting were studied to prepare composite materials in this paper.Firstly,orthogonal experiments were devised to investigate the optimum conditions of dispensing dispersions.A series of BP thickness were prepared.The results showed that porosity increased with the increase of thickness,and the strength and modulus decreased with the increase of thickness.Deionized water cleaning filtration process can effectively reduce the BP dispersion agent content to 3 percent up and down.The mechanical strength of BP was 2-9 MPa,modulus was 280-560 MPa,toughness is about 3 percent,and mechanical comprehensive property is stronger than that of BP obtained by vacuum-filtration.In the PA6/BP composite film prepared by solution ultrasonic impregnation,the polymer molecules were impregnated evenly into the internal microporous structure of the whole BP,forming a composite film with the interaction of the polymer and the carbon nanotube network structure,which was supported by each other.The polymer impregnation made BP expand about 15 μm.The presence of polymer in the composite membrane reduced the conductivity of the original BP,and the surface resistivity was 34-75 Ω.When the content of MWCNTs was 27%,the tensile strength of the composite film was increased from 42 MPa to 61 MPa,and the increase is about 45%.However,the toughness was reduced,the elongation at break was decreased from 3.5% to 2.4%,and the modulus rised from 1.2 GPa to 2.5 GPa,and the increase was about 1.8 times.In the last part of the paper,polyether ether ketone(PEEK)and nylon(PA6)composite films with high carbon nanotubes content were prepared by newly melt ultrasonic impregnation.The results showed that the melt polymer materials with high thermoplastic viscosity were impregnated into carbon nanoscale by the effect of ultrasound,forming two good polymer layer / carbon nanoscale / polymer sandwich composite films.The composite thin film prepared by melt ultrasonic impregnation method,in which the content of carbon nanotubes in PEEK composite film was 13.2%,the tensile strength of the film 93.3 MPa prepared by the casting process was raised to 103.1 MPa,the content of carbon nanotubes in the PA6 composite film was 14%,and the tensile strength of the thin film prepared by the casting process was enhanced from 31.51 MPa to 51.6 MPa.