Zinc Hydroxystannate/Carbon Nanotube Hybrids as Flame Retardant and Smoke Suppressant for Epoxy Resins

Novel hybrid flame retardants containing zinc hydroxystannate and carbon nanotubes (ZHS-CNTs) were synthesized using the coprecipitation method, and the structure and morphology of ZHS−CNTs were investigate using an X-ray powder diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and thermogravimetric analyzer (TGA). Then, the ZHS, CNTs and ZHS−CNTs were incorporated into EP, respectively, and the flame-retardant and smoke inhibition performance of the composites were compared and studied. Among the three composites, the EP/ZHS-CNT composites have the highest improvements on the fire resistance and smoke inhibition properties. With only 2.0 wt.% ZHS-CNT hybrids, the pHRR of EP/ZHS-CNT composite materials is reduced by 34.2% compared with EP. Moreover, the release of toxic gases including CO, CO(2) and SPR from the composites was also effectively inhibited. The mechanisms of flame retardant and smoke inhibition were investigated and the improved properties were generally ascribed to the synergistic flame-retardant effects between ZHS and CNTs, the catalyzing effect of ZHS and the stable network structure of CNTs.