The role of additives in composite materials has the following aspects:

1, the stabilization of resin matrix composite materials in the preparation, storage, processing and use process is easy to aging deterioration, performance is significantly reduced, in order to prevent or delay the aging of composite materials, in the preparation of composite materials, processing process is needed to add a class of stabilizer, also known as antioxidant. Stabilization additives are mainly used to suppress the aging process caused by oxygen, light and heat during the preparation, processing and application of composite materials.

2, improve mechanical properties for resin matrix composites, in order to improve some of their mechanical properties, such as tensile strength, hardness, rigidity, impact strength, etc., can be in the preparation of composite materials, add some additives that can improve the mechanical properties. For example, after the cross-linking curing of epoxy resin matrix composite material, the hardness is larger and the strength is higher, but the toughness is poor and the impact resistance is not ideal. In order to improve its impact resistance, additives can be added to improve the toughness.

3, improve the processing performance of composite materials in the preparation and processing process often add some diluent, in order to improve the processing performance of composite materials, such as improving fluidity and release property. The addition of diluent can reduce the viscosity of the resin, improve the infiltration of the adhesive liquid to strengthen the material, but also easy to transfer the energy released during the curing process of the resin, and can properly extend the use of the adhesive. The addition of lubricants can improve the lubricity between polymer molecules and between polymer and reinforcing material, thus improving the workability of composite materials.

4, flame retardant effect with the rapid expansion of composite materials in aviation, automobile, construction and electrical appliances and other applications, the demand for its flame retardant performance is increasingly high, resin matrix composite matrix is mostly composed of hydrocarbons organic polymer, with flammability, so in the processing of composite materials, It is necessary to add a class of additives to make the composite material meet certain flame-retardant requirements, this class of additives is known as flame retardant.

5, improve the surface performance in order to prevent the damage of static electricity generated during the processing and use of composite materials, a class of surfactant additives are often added in the preparation of composite materials, in order to improve the surface performance of composite materials, such additives include antistatic agents and anti-fogging agents.

6, improve the appearance quality In the processing or preparation of composite materials and its products, in order to improve the appearance quality of composite materials and its products, often add a class of additives that can give the appearance of composite materials smooth or make products with a variety of colors, such additives have colorants and lubricants.