In the fields of modern industry and construction,the demand for high-temperature protection and fire sealing is increasing day by day.Ceramics functionalized silicone rubber and inorganic silicone sealant are two important special materials commonly used in extreme temperature or fire risk scenarios.Although both are based on"silicon"as the core component,there are significant differences in their material properties,functional positioning,and application scenarios.This article will provide in-depth analysis from the aspects of chemical composition,performance,practical applications,and selection suggestions.

 

　　1、Core material composition and reaction mechanism

 

　　Ceramicizable silicone rubber

 

　　Base material:Made of silicone rubber(such as polydimethylsiloxane)as the base material,it has excellent elasticity and weather resistance.

 

　　Functional fillers:Ceramic fillers such as silicates(such as mica and kaolin),borates,glass powders,etc.are added,and some formulations contain flame retardants(such as aluminum hydroxide).

 

　　High temperature reaction mechanism:At temperatures above 300°C,the thermal decomposition of silicone rubber produces a silica skeleton,which combines with ceramic fillers to form a continuous and dense ceramic layer(such as mullite structure),isolating oxygen and heat and achieving"self ceramicization in fire".

 

　　Inorganic silicone sealant

 

　　Matrix material:mainly composed of inorganic silicates(such as sodium silicate,potassium silicate)or silica sol,with some containing a small amount of organic silicon modified components.

 

　　Curing characteristics:By evaporating water or reacting with CO₂,a rigid silicon oxygen network structure is formed.

 

　　High temperature tolerance:directly dependent on the high temperature resistance characteristics of inorganic components(such as silicate melting points above 1000°C),no chemical structural transformation occurs at high temperatures,but long-term exposure may lead to embrittlement due to thermal stress.

 

　　2、Typical application scenarios and limitations

 

　　Ceramicizable silicone rubber

 

　　Core application:

 

　　(1)Fireproof coating for cables/optical cables(protecting the integrity of the circuit in case of fire);

 

　　(2)Building fire sealing(such as pipe penetrations,elevator shafts);

 

　　(3)Sealing of aerospace engine compartments(balancing vibration environment and sudden fire incidents).

 

　　Advantages:It combines elasticity and active fire resistance,suitable for dynamic sealing scenarios.

 

　　Limitations:High cost,long-term exposure to high temperature environments(non fire)and easy aging.

 

　　Inorganic silicone sealant

 

　　Core application:

 

　　(1)Sealing of welding seams in industrial furnaces and boilers;

 

　　(2)Sealing of high-temperature components in automobile exhaust pipes and gas turbines;

 

　　(3)Heat resistant encapsulation of electronic components(such as power device heat dissipation packaging).

 

　　Advantages:Ultra high temperature tolerance(>1000°C),lower price.

 

　　Limitations:Inelasticity,poor vibration resistance,and cannot be adjusted after construction.

 

　　3、Future Development Trends

 

　　Composite:Develop organic-inorganic hybrid materials that balance elasticity and ultra-high temperature resistance.

 

　　Intelligence:Integrating temperature sensing function into ceramicizable silicone rubber to achieve fire warning.

 

　　Environmental Protection:Reduce the use of heavy metal fillers in two types of materials and promote halogen-free flame retardant systems.

 

　　Conclusion:The essential difference between ceramicized silicone rubber and inorganic silicone sealant lies in the functional positioning of"active fire resistance"and"passive high temperature resistance".In practical engineering,selection should be based on the temperature curve,mechanical load,and safety level of specific scenarios.With the advancement of materials science,breakthrough technologies may emerge in the future,further blurring the boundaries between the two and providing better solutions for sealing in extreme environments.