Study on the Interface Control and High Performances of Epoxy Vitrimer/Carbon Nanotube Composites
The mechanical properties of epoxy vitrimers are reduced due to the introduction of abundant dynamic covalent bonds.In this study,the properties of epoxy vitrimers were modified by the multiwalled carbon nanotubes(PIL-MWCNTs)that were modified by the in-situ polymerization of poly(ionic liquid)(PIL).The results show that the tensile strength,elongation at break,impact toughness,and fracture toughness are respectively increased by 79.5%,1 851.6%,158.3%and 404.4%.This is due to the adsorption of PIL on the surface of carbon tubes,which promotes the carbon tube dispersion and enhances the interactions between the carbon tubes and the matrix.In addition,compared with the unmodified system,the KIcof epoxy vitrimers modified by PIL-MWCNTs is increased by 158.3%and the stress relaxation time is decreased by 16.7%.The strong interfacial bonding force of PIL-MWCNTs causes the plastic deformation of the matrix and the crack deflection,crack blunting and crack bridging of MWCNTs,which toughens the epoxy vitrimers.In addition,the mechanical properties of PIL-MWCNTs system remain above 80%after remodeling(above 70%for the MWCNTs system),the initial thermal decomposition temperature is increased by 6.2℃,and the carbon residue is decreased by 14.1%.This paper provides a simple and efficient nanoparticle dispersion method to significantly improve the mechanical and thermo-mechanical properties of epoxy vitrimers.
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