Microstructure and dielectric properties of bismaleimide composite synergistically modified by graphene oxide and polyetheretherketone

Sulfonated polyetheretherketone (SPEEK) was prepared by using concentrated sulfuric acid to modify polyetheretherketone (PEEK). The graphene oxide (GO) was obtained by the modified Hummers method, and the GO was functionalized with silane coupling agent KH560. Diallyl bisphenol A (BBA) and bisphenol A bisallyl ether (BBE) were reactive diluents, and bismaleimide (BMI) resin was the reactive monomer to synthesize resin matrix (MBAE). The KH560-GO/SPEEK/MBAE composites were prepared in-situ polymerization by doping 5 wt% SPEEK and 0.1–0.8 wt% KH560-GO. The microstructure of KH560-GO were characterized and the results showed that KH560 has successfully grafted on the surface of GO by FT-IR and XRD, GO exhibited clear lamellar structure, few layers and folds on the surface, KH560-GO has been embedded in the middle of SPEEK phase or SPEEK is coated on KH560-GO surface, which is tightly combined with the matrix to form a multi-phase structure with irregular morphology. The dielectric properties of the KH560-GO/SPEEK/MBAE composite material showed that the dielectric constant and dielectric loss decreased slightly, and the volume resistivity was significantly improved, which is 122.7% higher than that of polymer matrix, when the content of KH560-GO is 0.3 wt% and the SPEEK is 5 wt%.