Spray-Drying-Assisted Layer-by-Layer Assembly of Alginate, 3-Aminopropyltriethoxysilane, and Magnesium Hydroxide Flame Retardant and Its Catalytic Graphitization in Ethylene–Vinyl Acetate Resin

Alginates (nickel alginate, NiA; copper alginate, CuA; zinc alginate, ZnA) and 3-aminopropyltriethoxysilane (APTES) were alternately deposited on a magnesium hydroxide (MH) surface by the spray-drying-assisted layer-by-layer assembly technique, fabricating some efficient and environmentally benign flame retardants (M–FR, including Ni–FR, Cu–FR, and Zn–FR). The morphology, chemical compositions, and structures of M–FR were investigated. With 50 wt % loading, compared with EVA28+MH, the peak heat release rate, smoke production rate, and CO production rate of EVA28+Ni–FR decreased by 50.78%, 61.76%, and 66.67%, respectively. The metals or metal oxide nanoparticles arising from alginates could catalyze the pyrolysis intermediates of EVA into graphene and amorphous carbon, which could bind the inorganic compounds (the decomposition products of MH and APTES) together and form some more protective barriers. For each M–FR, the flame retardant and smoke suppression efficiency were different, which were caused by t...