The materials of non-metallic expansion joints mainly include a variety of non-metallic materials, which are selected based on their performance in specific working environments, such as high temperature resistance, corrosion resistance, flexibility, sealing and insulation. The following are common non-metallic expansion joint materials:
Fiber fabricCommonly used fibrous fabrics include glass fiber, aramid, polyester, polyimide, and the like. These materials have good strength and heat resistance and are resistant to abrasion and chemical attack.
Rubber: Natural or synthetic rubber, such as nitrile (NBR), neoprene (CR), hydrogenated nitrile (HNBR), etc., are used where elasticity and chemical compatibility are required.
High temperature resistant material：
Silicone rubber: It has good high and low temperature resistance and is suitable for a wide range of temperatures.
Fluorine rubber (FKM): Excellent heat resistance and chemical resistance.
Polytetrafluoroethylene (PTFE): Extremely high heat resistance and chemical stability while having a low coefficient of friction.
Aluminum silicate fiber: Excellent high temperature resistance for high temperature insulation and sealing.
Ceramic fiber: It is used in extremely high temperature environment with good heat insulation and fire resistance.
Thermal insulation material: Such as rock wool, calcium silicate, perlite, etc., used to reduce heat transfer and protect non-metallic expansion joints from high temperatures.
Composite: The above materials are combined with other reinforcing materials (e.g. stainless steel wire mesh, metal foil) to form a multilayer composite structure to enhance the strength and durability of non-metallic expansion joints.
The skin (overlay) of a non-metallic expansion joint is usually composed of multiple layers of the above materials, each layer of material serves a different purpose depending on its characteristics, such as high temperature resistance, sealing, strength support, etc. This composite structure enables the non-metallic expansion joint to cope with complex working conditions, such as high temperature, high pressure, corrosive media, etc., and provides good displacement compensation ability.