Preparation And Interface Design Of Micro/nano Carbon/Polymer Functional Composites

Carbon nanomaterials(such as carbon fibers and carbon nanotubes)have many excellent electrical conductivity and mechanical properties,and become important functional composites components for the preparation of functional polymer composites.In this paper,three kinds of polymer materials were selected such as polyetheretherketone,polyethylene and nylon,carbon fibers and carbon nanotubes were used as functional components to prepare high-strength and wear-resistant,stable antistatic and high-strength conductive functional polymer composites,so as to meet the more demanding and high-performance requirements of polymer composites with the development of science and technology.And revealing the law of the influence of the interface on the function,which laying a theoretical foundation for the design of functional polymer composites.This paper mainly includes the following three aspects(1)CCF/polyetheretherketone(PEEK)composites were prepared by using polyethersulfone(PES)as tertiary component and activated PES as surface modifier for continuous carbon fiber(CCF)respectively.The research focuses on the effects of the preparation process on the properties of the CCF/PEEK composites.The results show that for the CCF/PEEK composites prepared with PES as tertiary component,when 16 wt%of CCF was filled,the surface resistance decreases to 107-109 ?,appearing conductive percolation state,and the friction coefficient reduces to the lowest value of 0.2430.The tensile strength,bending strength and impact strength of CCF/PEEK composites filled with 30 wt%of CCF with surface modifier by activated PES are increased to 236.2 MPa,345.1 MPa and 12.3 kJ/m2 respectively,compared with the CCF30/PEEK composites without PES modification,with the good dispersion of CCF and better interface adhesion between PEEK and CCF surface modified by PES.The tribological results indicate that the friction properties of the composites depend not only on the distribution of CCF in the matrix,but also on the interface force between CCF and the matrix(2)The dispersion and distribution of carbon nanotubes(CNTs)on/in the polymer composites are greatly affected by the molding technology progress,which results in different electrical conductivity.The uncontrollability electrical conductivity has limited the application of conductive polymer nanocomposites.To enhance the dispersion stability of CNTs in polymer matrix,sub-micron calcium carbonate isolated CNTs(smCaCO3@CNTs)were selected based on the fact that smCaCO3 is much easier to disperse in polymer in comparison with CNTs.This good dispersion of CNTs in smCaCO3@CNTs/PE was characterized by transmission electron microscope and Raman mapping.The electrical performance test results show that when 0.5 wt%of CNTs filled in sm CaCO3@CNTs/PE,the percolation network begins to form;when CNTs filled increases to 1-2 wt%,the surface resistance of smCaCO3@CNTs/PE ranges from 106 to 109 ? almost not affected by the molding technology process(Compression Molding or Injection Molding).The possible reason is that the isolated CNTs by smCaCO3 in polymer matrix are favorable for the formation of the stable conductive network.(3)The application demand of high-strength conductive nylon composites with surface resistance within 1000 ? in the field of robotic equipment is increasing.Continuous carbon fiber(CCF)as the conductive functional phase and nylon(PA6,PA66)as the polymer matrix to prepare conductive nylon composites.The research focuses on the effects of CCF surface functional groups and PA-based melt viscosity on the electrical,mechanical,rheological and dynamic mechanical properties of composites.The results show that when 25 wt%CCF was filled,the surface resistance of CCF-1-25/PA66 composites prepared by CCF with urethane(-CONH-)functional groups is 2×102 ?,which is three orders lower than that of CCF-2-25/PA66 composites with epoxy functional groups on the surface resistance.The results of dynamic mechanical analysis show that compared with CCF-2,the composites prepared by CCF-1 have higher storage modulus,loss modulus,and exhibit a lower damping coefficient(tan?),which indicates that CCF with urethane functional groups is easy to disperse uniformly in the PA66 matrix and form an effective conductive network.Compared with CCF-2-25/PA66 composites,the tensile strength and flexural strength of CCF-1-25/PA66 composites are reduced by 8.1%and 6.0%respectively,which indicates that CCF with epoxy functional groups and PA66 matrix have a better interface.Compared with CCF-2-25/PA66 composites,the surface resistance of CCF-2-25/PA6 composites is reduced by an order.Therefore,the surface functional groups of conductive phase,the distribution of CCF in the PA matrix,the viscosity of PA matrix and the interface between CCF and PA matrix are the key factors affecting the mechanical,thermal and electrical properties of the PA composites.