Silane coupling agent belongs to a class of silicon-containing small molecule compounds. Its molecule has two functional groups, one end is an inorganic siloxane group, which can undergo hydrolysis reaction in the presence of water; the other end is an organic functional group containing active groups such as olefins, phenols, and amines. Therefore, it can be regarded as a special molecule that bridges inorganic and organic substances. This unique "two-end connection" structure allows silane coupling agents to be widely used to connect inorganic fillers with organic polymers to prepare inorganic-organic composite materials, such as glass fiber reinforced plastics (GFRP) and sealants. It can greatly improve the composite interface bonding strength, thereby improving the mechanical properties of the material.
Application of silane coupling agent
1. Filled composite materials
It can chemically bond to the surface of inorganic fillers, connect fillers with organic matrices, thereby improving interfacial bonding, improving filler dispersion, and inhibiting stress concentration. This effectively improves the impact resistance and overall mechanical properties of composite materials. At present, it has become a key interface treatment agent for the manufacture of red fiber reinforcement, wood powder/carbon powder reinforcement and mineral-filled plastics and rubber.
2. Sealant
All kinds of room temperature curing silicone sealants mostly use silane coupling agents as crosslinking agents. The mechanism is that under the catalysis of acetate, acyloxysilane first reacts with trace moisture in the air to form silanol, which can undergo polycondensation with siloxane groups to form a three-dimensional silicone rubber with a network crosslinking, thereby achieving room temperature curing and sealing. This type of product is mainly used for bonding and sealing of buildings and electronic appliances.
3. Resin coating
Added in small amounts to paint primers. Its highly active functional groups can react chemically with inorganic matrices such as metals, glass, and ceramics to generate corresponding salts, so that the coating can be firmly bonded to the coated substrate, greatly improving the service life.
4. Adhesion promoter
It can effectively promote the interfacial bonding between the fiber and the metal or ceramic matrix in glass fiber and carbon fiber composite materials, and enhance the bonding strength. At the same time, under high temperature and humid conditions, it can also inhibit interfacial debonding and extend the service life of the composite material.
5. Other applications
In addition, silane coupling agents can also be used in many fields such as polymer blending modification, crosslinking, and wood antiseptic. In general, connecting inorganic and organic material systems is its unique advantage.