The application of expandable graphite in rubber is mainly reflected in the following aspects:
Flame retardant modification: Expunable graphite is a typical physical expunable flame retardant. When exposed to fire or heat, it can form an expunable carbon layer covering the polymer surface, thereby playing a role in hindering the spread of flames and heat. Adding expandable graphite to rubber can significantly improve the flame retardant performance of rubber. For instance, when expandable graphite is added to silicone rubber, as the particle size of expandable graphite decreases and its addition content increases, the flame retardant performance of silicone rubber composites gradually improves. When the mesh count of expansable graphite is 80 and the addition amount is 8 parts, the limiting oxygen index of the composite material can reach 31.2% and pass the vertical burning test at grade V-0.
Fireproof sealing and flame retardant applications: The expanded carbonized layer formed by expandable graphite carbon has excellent heat insulation performance and high-temperature resistance. In rubber products, such as fireproof sealing strips, the expansibility, high-temperature resistance and thermal insulation of expandable graphite make it an excellent sealing material. This sealing strip has the function of blocking the flow of smoke from beginning to end in a fire. Expellable graphite can instantly expand in volume when exposed to high temperatures, displacing the surrounding air and thus achieving the effect of fire prevention and flame retardancy.
Impact on rubber properties: Although expandable graphite can significantly enhance the flame retardancy of rubber, it may also have certain effects on the mechanical properties and thermal stability of rubber. Generally speaking, as the addition amount of expandable graphite increases, the tensile strength of rubber may gradually decrease, while the elongation at break may gradually increase. In addition, the addition of expandable graphite may also reduce the thermal stability of rubber.
