Study on mechanical properties of nano-Sb₂O₃/BEO-PBT flame retardant composites reinforced by surface-modified basalt fiber

In this study, the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and silane coupling agent N-(β-aminoethyl)-γ-aminopropylmethylbimethoxy silane (KH602) were used as modifiers to improve the interfacial bonding strength between basalt fiber (BF) and PBT matrix. Using single modified and compound modified BF as reinforcing fillers, BF/nano-Sb2O3/BEO-PBT composites were prepared by injection molding. The structure characteristics of modifiers on the surface of BF were studied by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The mechanical, crystallization, thermomechanical properties and flame retardancy of BF/nano-Sb2O3/BEO-PBT composites were investigated using the tensile testing machine, impact testing machine, scanning electron microscopy (SEM), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA), limiting oxygen index (LOI) and vertical combustion tester, respectively. The results showed that the CTAB and KH602 were successfully introduced into the surface of BF and the interfacial bonding strength between BF and PBT matrix was increased. The addition of BF did not reduce the flame retardancy of nano-Sb2O3/BEO-PBT composites. The tensile strength and Young's modulus of the BF/nano-Sb2O3/BEO-PBT composites were significantly improved and the notch impact strength was slightly increased with the use of modified BF. In terms of the mechanical properties of BF/nano-Sb2O3/BEO-PBT composites, the BF obtained an excellent enhancement effect on the composites when modifiers were applied by means of the compound modification with CTAB and KH602.