Study On Dispersion Method And Properties Of Multi-walled Carbon Nanotubes Modified Polymer Composites

Polymer/carbon nanotube composite material has a unique one-dimensional nanotube dispersion microstructure,which exhibits better mechanical properties,electrical properties and thermal properties than pure polymers,and Polymer/carbon nanotube composite materia has broad application prospects in many fields.However,the research on the dispersion and composite methods of carbon nanotubes in polymers is still in an immature stage,and many related problems remain to be solved,leading to bottlenecks in the industrial production of carbon nanotube/polymer composites.In order to solve the problems of dispersion and properties in carbon nanotube/polymer composites,the dispersion of carbon nanotubes in polymers and the properties of polymer composites were used as the main research objects to prepare polystyrene/carbon nanometers.Tube composites and polypropylene/carbon nanotube composites were analyzed and characterized to characterize the structure and properties of the materials.Firstly,the two methods of solution and melting were used to study the preparation method,microstructure and mechanical properties of polystyrene/carbon nanotube composites.Electron microscopy analysis,contact angle,impact strength and conductivity test were used.The results show that the carbon nanotubes can be well dispersed in the composite at low content of 2%and 4%.The agglomeration phenomenon is obvious at high content,which affects the mechanical properties of the material.The impact strength indicates that the carbon nanotubes can improve the toughness of the composite.The impact strength of composites increases first and then decreases with the increase of carbon nanotube content.The impact strength of 4%polystyrene/carbon nanotube composites increases by 27.9%compared with pure polystyrene.Conductivity test shows that the conductivity of the composite material increases with the increase of the content of carbon nanotubes.When the carbon nanotube content is 10%,the electrical conductivity of the composite material can reach the order of 10^-410^-3S/cm.The contact angle test shows that With the increase of carbon nanotube content,the contact angle of the interface of the composite increases,and the hydrophilic property of the material becomes weak.Secondly,the carbon nanotubes were subjected to alkali modification,hydroxylation modification,oxidation treatment,esterification modification,acidification modification and other chemical modification.The properties and dispersion of carbon nanotubes before and after modification were characterized.The XRD spectrum shows that the structure of the carbon nanotubes is improved,and the characteristic peaks of the carbon nanotubes are enhanced.The free sedimentation experiments show that the dispersibility of the carbon nanotubes in the carbon tetrachloride and methylene chloride is improved.Finally,a polypropylene/carbon nanotube composite was prepared by the melt-mixing method with application prospects.The results show that the carbon nanotube toughened polypropylene can increase the flexural strength of the composite from 46.6 MPa to 72.7 MPa,DSC and The TG test showed that the thermal stability of the carbon nanotube-added material was improved.The Huck Rotary Rheometer test showed that the storage modulus G'of the melt after the addition of the carbon nanotubes,the loss modulus G'and the viscosity?*increased.The rheological properties of the material deteriorate.After the carbon nanotubes are modified by hydrogen peroxide,they can be combined with polypropylene to improve the rheological properties of the composite.