Magnesium hydroxide – phytic acid compound improved fire performance and reduced smoke loss in polyethylene. The natural inorganic compound, magnesium hydroxide, was reacted in water with phytic acid, a biological compound rich in phosphorus found widely in plants. The product (termed MHPA) was tested at 33% loadings of MHPA, MHPA+MH or MH, in high-density polyethylene (HDPE). UL 94 v-2 was achieved only with MHPA+MH, with peak heat release rate reduced by nearly -40% and total smoke production by -65% compared to neat HDPE. Mechanical properties (tear strength, tensile strength, shore hardness) were generally better when MHPA was included that with MH alone, but were significantly lower than for neat HDPE.
“Development of bio-based magnesium phosphate flame retardant for simultaneously improved flame retardancy, smoke suppression and mechanical properties of HDPE”, X. Feng et al., J Appl Polym Sci. 2023;140:e53927 https://doi.org/10.1002/app.53927