Surface modification of h-BN and electric field control of its orientation in sulfonated polyetheretherketone

Abstract

Since thermally conductive fillers easily aggregate when introduced into polymer matrix, it is essential to apply a modifier to enhance the dispersion of the filler. In current study, the surface of boron nitride (h-BN) is firstly modified by employing a double modification process and then added into sulfonated polyetheretherketone (SPEEK) to form the composite materials. Four different kinds of samples of double-modified h-BN were obtained. Ultimately, the XXX@h-BN/SPEEK (XXX denoted as modifier, i.e. PDA, VTMS, TEOS, and APS) flexible film with the horizontally oriented XXX@h-BN was produced by heating the mixture under an external electric field. The test results indicate that the thermally conductive filler PDA@h-BN (PDA: polydopamine), which was prepared by modifying OH@h-BN with PDA, loaded into SPEEK, and electrically oriented, shows the best overall performances. With a high tensile strength of 43.24 MPa and good flexibility, PDA@h-BN/SPEEK flexible film exhibits an in-plane thermal conductivity of 2.3 Wm⁻¹ K⁻¹ at a filling ratio of 10 wt%. The sample may be bent at a steep angle without breaking down and can recover to original shape bearing its high degree of flexibility.