Messi Biology states that in modern society, where high-speed railways run rapidly and data centers operate at high speeds, wires and cables serve as the “blood vessels and nerves” for energy and signal transmission, making their safety performance of paramount importance. Within the core materials of cable sheathing, magnesium hydroxide, a seemingly ordinary white powder, is becoming a key force in safeguarding cable safety through advanced modification technologies.
The reason magnesium hydroxide has become a core material for cable compound modification lies in its unique flame-retardant mechanism. When a cable is exposed to high temperatures or fire, magnesium hydroxide decomposes at temperatures above 340°C. This process not only absorbs a large amount of heat to lower the temperature of the combustion zone, but also releases crystalline water to dilute the concentration of combustible gases. The resulting magnesium oxide then forms a dense protective layer that insulates oxygen and blocks heat transfer. Unlike traditional halogen-based flame retardants, this flame-retardant process releases no toxic gases and can increase smoke light transmittance threefold, effectively preventing “secondary hazards” during a fire at the source.
However, untreated magnesium hydroxide has inherent limitations: its highly hydrophilic surface results in poor compatibility with hydrophobic cable substrates like polyethylene, making it prone to agglomeration, which causes uneven flame retardancy and reduces material flexibility. Therefore, modification technology is crucial to overcoming this bottleneck. By using modifiers like branched polyethylenimine to construct a three-dimensional network structure, the interfacial adhesion between magnesium hydroxide and the substrate can be significantly enhanced, allowing for uniform dispersion within the cable compound. Furthermore, hexagonal platelet-shaped magnesium hydroxide offers distinct advantages; its regular structure enables tight packing to form an efficient barrier network at lower loading levels while simultaneously improving the tensile properties of the cable.
Modified magnesium hydroxide enables a dual leap in both safety and performance for cable compounds. Adding 30 to 70 parts of modified magnesium hydroxide into the formulation allows cross-linked polyethylene (XLPE) sheathing compounds to meet the UL94 V-0 flame retardancy standard while maintaining a tensile strength retention rate of over 80%. This satisfies flame retardancy requirements without sacrificing cable flexibility. This environmentally friendly flame-retardant material is already widely used in high-end fields such as high-voltage cables for new energy vehicles, rail transit signal cables, and vertical cables in high-rise buildings, maintaining stable performance under high-temperature and high-voltage environments.
Of further note are its eco-friendly properties. Modified magnesium hydroxide flame retardants are non-toxic and harmless. Additionally, magnesium hydroxide from waste cables can be recovered for use in industrial flue gas treatment, achieving the circular utilization of resources. As nanotechnology and surface modification processes continue to advance, magnesium hydroxide is expected to achieve greater breakthroughs in improving flame retardant efficiency and lowering required loading levels. This will provide more robust protection for cable safety, ensuring that energy transmission remains both highly efficient and secure.