Preparation of nanocomposites with epoxy resins and thiol-functionalized carbon nanotubes by thiol-ene click reaction

Abstract

Carbon nanotubes (CNTs) have attracted increasingly interest in preparing CNTs/epoxy nanocomposites for improving thermal and mechanical properties. The well distribution of prime CNTs in epoxy matrix is still a challenge due to the strong interaction among nanotubes and property of self-aggregation. Here, we report a highly efficient approach to functionalize prime CNTs by a thiol-ene click reaction between double bonds of CNTs and thiol groups of mercaptans, and the resulted in thiol-functionalized CNTs with different chemical chains show well dispersion in ethyl acetate and epoxy. The thiol-functionalized CNTs show a positive effect on reinforcing and toughening diglycidyl ether of bisphenol-A (DGEBA). With an increase in the thiol-functionalized CNTs content, the mechanical and thermal properties of the CNTs/DGEBA nanocomposites, including tensile, flexural and impact strengths, and thermal conductivity, increase first and then decrease. The maximum improvements on the tensile, flexural, impact strengths and thermal conductive were 43.75%, 25.11%, 196.44% and 33.81%, respectively. These grafted mercaptans chains play a bridging action between CNTs and epoxy matrix to supply a strong interaction, substantiated by their good rheological property and ductile SEM micrographs. Both the simple method of thiol-functionalized CNTs and preparation of CNTs/DGEBA nanocomposites will supply dependable data for wide application of CNTs. • A highly efficient thiol-ene click reaction was used to functionalize prime CNTs. • Thiol-functionalized CNTs showed well dispersion in ethyl acetate and epoxy. • Thiol-functionalized CNTs could reinforce and toughen diglycidyl ether of bisphenol-A. • A strong interaction between CNTs and epoxy matrix was substantiated by rheological property and SEM.