Zinc hydroxystannate dripped on magnesium hydroxide flower for enhancing smoke suppression and toxicity reduction properties of epoxy resin

In order to reduce the emission of smoke and toxic gases during the combustion of epoxy resin (EP), inspired by the structure of flowers after rain, a novel low-cost flame retardant (FMH@ZHS) was prepared by using flower-like magnesium hydroxide (FMH) as the flower and zinc hydroxystannate (ZHS) as the raindrop. The tensile strength of EP/3FMH@ZHS increased by 13.7% compared with EP/3FMH. Moreover, the 3 wt% FMH@ZHS hybrid material increased the limited oxygen index value of the EP composite to 27.6% while suppressing the dripping phenomenon during combustion, achieving self-extinguishing characteristic. Meanwhile, compared with pure EP, peak heat release rate, peak smoke production rate, total smoke production, and peak carbon monoxide production rate of EP/3FMH@ZHS decreased by 34.6%, 55.6%, 41.8%, and 50.0%, respectively. The flame retardant mechanism showed that during the combustion process, the catalytic char formation of magnesium oxide, zinc oxide, and stannic oxide generated from FMH@ZSH can promote the formation of a denser and continuous char layer, inhibiting the transport of flammable gases, toxic gases and heat and improving the fire safety of EP composites. In conclusion, this biomimetic material provided a good approach for the industrial application of EP.

Automated summary

In this study, a novel low-cost flame retardant was prepared by mimicking the structure of flowers after rain. The hybrid material showed improved mechanical properties and flame retardancy in epoxy resin composites.