Nonfluoride-modified halloysite nanotube-based hybrid: potential for acquiring super-hydrophobicity and improving flame retardancy of epoxy resin

With the development of modern engineering technology, the development of high-performance and multifunctional polymer materials has been promoted. In this work, a novel nanohybrid based on chitosan engraved zinc and iron mixed oxyhydroxide at the presence of halloysite nanotubes (HNTs) as the carrier, followed by surface capping with stearic acid to obtain super-hydrophobic HNT@CSZFMOH nanofiller. The as-obtained HNT@CSZFMOH nanofiller was incorporated into epoxy resin (EP) matrix. With the addition of 3 wt.% HNT@CSZFMOH, the peak heat release rate and peak smoke production of the EP nanocomposite decreased by 35% and 32%, respectively. This excellent flame retardancy is attributed to that the enhanced physical barrier derived from HNT@CSZFMOH, and the dense, highly graphitized char layer formed by catalytic charring of ultrafine FeOOH and ZnOOH nanoparticles. Meanwhile, the nanohybrid imparted outstanding hydrophobicity to the hydrophilic substrate EP with the water contact angle (CA) of 159°. EP-matrix nanocomposite exhibited desired self-cleaning performance as well as good resistance against corrosive liquids (acid and alkaline solutions) and ultraviolet irradiation. The present approach, with simple procedures and desired environmental acceptance, could provide feasible pathway to fabricating multifunctional polymer–matrix composites.