Magnesium hydroxideThe flame retardant effect of flame retardant is to prevent or inhibit the speed of physical or chemical changes in the combustion process of polymer materials. The following will introduce the flame retardant effect of magnesium hydroxide inhibitor in detail.
1, the endothermic effect of its role is to make the temperature rise of polymer materials difficult, for example, borax has 10 molecules of crystal water, due to the release of crystal water to capture 141.8kJ/mol heat, because of its endothermic and the temperature rise of the material is inhibited, resulting in flame retardant effect. The flame retardant effect of hydrated alumina is also due to its thermal dehydration to produce endothermic effect. In addition, some thermoplastic polymer cracking often produced droplets, because can leave the combustion zone to remove the heat of reaction, can also play a certain flame retardant effect.
2. The covering effect is to generate a stable covering layer at a higher temperature, or decompose to generate a foam-like substance, which covers the surface of the polymer material, so that the heat generated by combustion is difficult to pass into the material, so that the flammable gas generated by the thermal decomposition of the polymer material is difficult to escape, and the material is isolated from the air, thus inhibiting the material from cracking and achieving the flame retardant effect. Such as phosphate ester compounds and fire retardant foaming coatings can play a role according to this mechanism.
3. Dilution effect Such substances can produce a large amount of non-combustible gas when they are decomposed by heat, so that the combustible gas produced by the polymer material and the oxygen in the air are diluted and cannot reach the flammable concentration range, thereby preventing the polymer material Ignition and combustion. CO2, NH3, HCl and H2O, among others, can be used as diluent gases. Amine phosphate, amine chloride, amine carbonate and the like can generate such a non-flammable gas when heated.
4, transfer effect its role is to change the mode of thermal decomposition of polymer materials, thereby inhibiting the production of flammable gases. For example, cellulose is decomposed into charcoal and water by a dehydration reaction using an acid or an alkali, and thus it cannot be ignited and burned because a flammable gas is not generated. Amine chloride, amine phosphate, phosphate, etc. can be decomposed to produce such substances, catalytic material condensed ring carbonization, to achieve the purpose of flame retardant.
5. Inhibitory effect (capturing free radicals). The combustion of polymers is mainly a chain reaction of free radicals. Some substances can capture the active intermediates HO, H, O, HOO, etc. of the combustion reaction, inhibit the chain reaction of free radicals, and reduce the combustion speed until the flame is extinguished. Commonly used bromine, chlorine and other organic halogen compounds have this inhibitory effect.
6. Enhancement effect (synergistic effect) Some materials, if used alone, have no flame retardant effect or little flame retardant effect, and the use of multiple materials can enhance the flame retardant effect. The use of antimony trioxide and halogen compounds is a typical example. As a result, not only the flame retardant efficiency can be improved, but also the amount of the flame retardant can be reduced.
The above is the introduction of the flame retardant effect of magnesium hydroxide inhibitor, I hope it can be helpful to everyone.