Preparation And Properties Of CNTs/CF/PA10T Composites

Poly(decamethylene terephthalamide)(PA10T)is a new engineering material,which has good mechanical properties,heat resistance,dimensional stability and low production cost.It has a wide application prospect in automotive,aviation,electronics and other fields.Modified enhanced PA10 T material has also become a hotspot in research and application.Carbon fiber(CF)and carbon nanotube(CNTs)have good mechanical properties,electrical properties,thermal properties,high temperature resistance,chemical corrosion resistance,and are ideal modified fillers.The addition of a small amount of carbon fiber and carbon nanotube can reach or even exceed the performance of PA10 T composites enhanced by other fillers.In this paper,PA10 T was modified by carbon fiber and carbon nanotube fillers.On the basis of surface treatment of carbon fiber and carbon nanotube,the mechanical properties,electrical properties and thermal properties of CF/PA10 T and CNTs/CF/PA10 T composites were prepared and studied using a twin screw extruder,and the crystallization kinetics of the composites was explored.The results show that:(1)CF/PA10 T composites were prepared by melt blending.The results show that with the increase of carbon fiber content,the mechanical properties,thermal properties and electrical properties of the composites are improved to varying degrees.Scanning electron microscopy shows that carbon fiber is effectively dispersed,no obvious agglomeration phenomenon is observed,and the matrix has good compatibility with carbon fiber.(2)On the basis of CF/PA10 T composites prepared,CNTs/CF/PA10 T composites were prepared with 8% carbon fiber and 1%-5% carbon nanotubes as fillers.It was found that a small amount of carbon nanotubes and carbon fiber synergistically enhanced the properties of the material.Compared with PA10 T,the tensile strength,impact strength,thermal deformation temperature,thermal conductivity and conductivity of CNTs/CF/PA10 T composites with 3% carbon nanotubes increased by 79.1%,42.6%,51.7% and 89.9%,respectively,by 9 orders of magnitude.When the carbon fiber content was greater than 3%,CNTS tend to agglomerate in the matrix,which leads to degradation of their properties.At the same time,carbon nanotubes improve the compatibility between carbon fiber and matrix,and enhance the interface adhesion between the two.Thermogravimetric analysis showed that carbon nanotubes increased the initial thermal decomposition temperature of composites,reduced the maximum degradation rate,widened the processing window of materials,and improved the thermal stability of materials.(3)The crystallization kinetics of CF/PA10 T and CNTs/CF/PA10 T composites were studied by DSC.The results show that during the isothermal crystallization process,the crystallization peaks of carbon fiber and carbon nanotubes appear double peaks.In the process of non-isothermal crystallization,carbon fiber and carbon nanotube hindered the migration of long chain of matrix molecules,and the crystallization peak of CF/PA10 T composites widened slightly.At the same time,the crystallization temperature of CF/PA10 T composites increased at different cooling rates due to aberrant nucleation.It was found by Jeziorny method and Mo method that CF/PA10 T material exhibits disc-like growth at low cooling rate and spherulite growth at high cooling rate.CNTs/CF/PA10TPA10 T crystal exhibits disc-like growth at high cooling rate.The relative crystallization rate of the composites increased synchronously with the increase of the cooling rate of spherulite growth,while the crystallization rate of carbon fiber and carbon nanotubes decreased.