With the increase of sb203 content, the oxygen index of low smoke halogen-free aluminum hydroxide material has an obvious upward trend. The study also found that with the increase of Sb2O3 content, the amount of smoke increased and black smoke appeared, indicating that Sb2O3 only played a flame retardant role, but had little effect on smoke suppression.

The low-smoke halogen-free aluminum hydroxide halides decompose to release halides and halogen elements, and react with sb203 to produce trihalobin and halobin oxide. The carbonized layer formed by the reaction of three halogen brocade and plastic can insulate and shield the plastic under the plastic to prevent burning. The tensile strength of the system increases first and then decreases. This is because the content of Sb2O3 is small, the number of sb203 particles is small, and the dispersion is good, which plays a reinforcing role.
 

The tensile strength of low smoke halogen-free aluminum hydroxide increases with the increase of Sb2O3 content. However, when the Sb2O3 content continues to increase, the inorganic particles in the system increase, the plasticizer cannot penetrate well, and the contact angle with the material is large, resulting in uneven distribution in the system and weakening of the two-phase interface bonding force. With the increase of the number of inorganic particles in the system, the inorganic particles in the system cannot penetrate the system, the mechanical properties of the material decrease, the volume resistance of the system decreases, and the rate changes little.

The oxygen index of low-smoke halogen-free aluminum hydroxide increased with the increase of dose. With the increase of the amount of zinc borate, the amount of smoke was significantly reduced, and the color of the smoke gradually turned white. Zinc borate is a kind of powder with good dispersion, small particle size and easy to disperse in various resins. The combination of zinc borate and sb203 can improve the flame retardancy of sb203. Because zinc borate releases a large amount of crystal water and absorbs a large amount of heat during the combustion process, the heating rate of the polymer is delayed.

At the same time, the low smoke halogen-free aluminum hydroxide released by the water vapor dilution combustion gas, B2O3 in the polymer to form a glass-like film, isolated oxygen, play a flame retardant effect. Boron compounds, acting as flame retardants and curing phase flame retardants, produce HCI under combustion conditions. HCI reacts with zinc borate to form non-volatile zinc compounds. Combined with ferric oxide, it can improve the oxygen index and inhibit the smoke.

It can be seen that the tensile strength and elongation at break of the system gradually decrease with the increase of the amount of low smoke halogen-free aluminum hydroxide. This is because zinc borate is a filled flame retardant, its shape is different from PVC, plasticizer can not penetrate well, so its compatibility is poor with the increase of content, a large number of interfaces are formed in the system, easy to slip under the action of external force, resulting in the decline of mechanical properties.

Effect of the amount of zinc borate in low-smoke halogen-free aluminum hydroxide on hardness and volume resistivity. With the increase of zinc borate content, the hardness and volume resistivity of the system have increased to varying degrees, because it belongs to sb203 and other inorganic filled flame retardants, which play a filling role in the system for the same reason as polyamide trioxide.