Improving the mechanical, thermal, dielectric and flame retardancy properties of cyanate ester with the encapsulated epoxy resin-penetrated aligned carbon nanotube bundle

Epoxy resins-penetrated aligned carbon nanotube bundles (ACNTB) microcapsules (ACNTB@EP MCs) and pristine ACNTB with porous structure were introduced into thermosetting cyanate ester (CE) resins to prepare high performance CE composites. Owing to the epoxy resins-penetrated ACNTB with significantly decreased defects and the chemical interaction at the interface of MCs and CE resin, CE with appropriated MCs shows better comprehensive performance than CE/ACNTB composite when the two composites contain the same amount of ACNTB. CE with 5 wt% MCs (CE/5MCs) shows the optimal flexural strength, impact resistance and tensile strength, which are 59%, 45% and 32% higher than that of CE, respectively. CE with 15 wt% MCs (CE/15MCs) shows 24% higher in thermal conductivity, 35.1% lower in PHRR value than CE. CE/15MCs also exhibits the highest dielectric constant of 12.8-16.6 and a low dielectric loss of 0.022-0.066. The attractive performances of CE/MCs composites prove that the ACNTB@EP MCs are multi-functional fillers, which can simultaneously act as toughening agent, reinforcement while improving the thermal stability, flame retardancy and dielectric properties for high temperature thermosetting resins.