Coupling agents are a type of material with two separate functional groups: one can react with organic molecules, while the other can react with inorganic compounds on the surface of adsorbed water, establishing a strong link.

The role of silane coupling agents in composite materials is that they can react not only with certain groups on the surface of the reinforcing material, but also with the matrix resin, forming an interface layer between the reinforcing material and the resin matrix, which can transfer stress, enhancing the bonding strength between the reinforcing material and the resin, improving the composite material's performance, and preventing the pinning of the reinforcing material.

Organochromium complexes, silanes, titanates, and aluminium acid compounds are the four types of silane coupling agents based on their chemical structure and content.

Ⅰ. Silane coupling agents' functions

1. Silane coupling agents cross-linking

When a silane is grafted into the polymer backbone, it can generate siloxane connections between the polymer molecules, resulting in a three-dimensional mesh structure.

The moisture in the air activates this "cross-linking." coupling agents for silanes Silanes improve the thermal stability, creep resistance, hardness, and chemical resistance of coatings, adhesives, sealants, and composites by activating at room temperature.

2. Adhesion is improved by using silane coupling agents.

Silanes promote the adherence of adhesives, sealants, and coatings to substrates, especially in hot and humid circumstances. Silanes are often used to improve adhesion to glass, minerals, and metals, and they're also great for tough substrates including polyamides, sheet mouldings (SMC), acrylic resins, and polyvinyl chloride (PVC).

3. Coupling

Inorganic pigments and fillers can be combined with organic resins thanks to silanes. Coating auxiliary coupling enhances the moisture and chemical resistance of coatings, adhesives, and composites in most cases.

4. Unpredictability

In coatings and sealants, silanes aid in the dispersion of inorganic colors and fillers.

Ⅱ. Selection of the silane coupling agent

There are many different silane coupling agents, but the reactivity of a silane to react with the resin and so realize its value is the basis for its selection.

Epoxy silanes are being used in a variety of aqueous coatings and adhesive systems. Customers may need to compound with other coupling agents from various functional groups on occasion. Because epoxy functional groups react with functional groups such as amino, mercapto, hydroxyl, and carboxyl groups, whether or not a reaction is necessary, the proper product is chosen based on the needs of the customer.