The purpose of flame retardant technology is to make non-flame retardant materials have flame retardant properties, which are not easy to burn or self-extinguishing under certain conditions. It is a kind of material to provide security. The future development direction of flame retardants is good flame retardant effect, safety and environmental protection. For this reason, considerable manpower and resources have been invested in the research and development of new flame retardant technologies. Nowadays, several new flame retardant technologies have been developed. Next, we will introduce some new flame retardant technologies of environmental friendly flame retardants.

I. Surface Modification

Inorganic flame retardants have strong polarity and hydrophilicity, poor compatibility with non-polar polymer materials, and difficult to form good bonding and bonding interface. In order to improve the adhesion and interfacial affinity between polymer and polymer, surface treatment with coupling agent is one of the most effective methods. The commonly used coupling agents are silane and titanate. If the flame retardant effect of ATH treated with silane is good, the flexural strength of polyester and the tensile strength of epoxy resin can be effectively improved; ATH treated with ethylene-silane can be used to improve the flame retardancy, heat resistance and moisture resistance of cross-linked vinyl acetate copolymer. Titanate coupling agent and silane coupling agent can be used together to produce synergistic effect. After surface modification 2, superfine

Inorganic flame retardants are more and more popular because of their high stability, non-volatilization, low toxicity and low cost. However, its poor compatibility with synthetic materials and large amount of additives make the mechanical properties and heat resistance of the materials reduced. Therefore, modification of inorganic flame retardants to enhance their compatibility with synthetic materials and reduce their dosage has become one of the development trends of inorganic flame retardants. At present, superfine and nano-sized aluminium hydroxide (3Al (OH) is the main research and development direction. A large amount of 3Al (OH) can reduce the mechanical properties of the material. However, by filling 3Al (OH) with fine particles, it will play a role in plasticizing and reinforcing rigid particles, especially nano-materials. Because the function of flame retardant is controlled by chemical reaction, the smaller the size of flame retardant is, the larger the specific surface area is, and the better the flame retardant effect is. Ultra-fine is also considered in terms of affinity. It is because of the different polarity between aluminium hydroxide and polymer that the physical and mechanical properties of Flame Retardant Composites decrease. Ultrafine and nano-sized 3Al (OH) enhances the interfacial interaction and can be evenly dispersed in the matrix resin, which improves the mechanical properties of the blends more effectively.

3. Compound synergy

In practical production and application, there are always some defects in a single flame retardant, and it is difficult to meet higher and higher requirements by using a single flame retardant. The compounding technology of flame retardants is to compound phosphorus, halogen, nitrogen and inorganic flame retardants, or to seek the best economic and social benefits. Combination technology of flame retardants can synthesize the advantages of two or more flame retardants, make their performance complementary, reduce the amount of flame retardants, improve the flame retardant properties, processing properties and physical and mechanical properties of materials.

IV. Crosslinking

The flame retardancy of crosslinked polymers is much better than that of linear polymers. Adding a small amount of crosslinking agent during the processing of thermoplastic can make the plastic become part of the network structure, improve the dispersibility of flame retardant, help to produce coking effect when plastics are burning, improve the flame retardant performance, and increase the mechanical and heat resistance of products.

V. Microencapsulation

The application of microencapsulation in flame retardants is a new technology developed in recent years. The essence of microencapsulation is to crush and disperse flame retardants into particles, encapsulate them with organic or inorganic substances, form microencapsulated flame retardants, or use inorganic substances with large surface as carriers to absorb flame retardants in the voids of these inorganic carriers and form honeycomb microencapsulated flame retardants. Microencapsulation of bromine environmental friendly flame retardants has the following advantages: it can improve the stability of flame retardants; it can improve the compatibility of flame retardants and resins, and improve the physical and mechanical properties of materials; it can greatly improve the various properties of flame retardants and expand their application scope.

VI. Nano Flame Retardant Technology

Some nano-materials have the function of preventing combustion. By adding them as flame retardants into combustible materials, their special size and structure effects can change the combustibility of combustible materials and make them fire-resistant materials. Nanotechnology can change the flame retardant mechanism and improve the flame retardant performance. Because of the small size and large specific surface area of nanoparticles, the surface effect, volume effect, quantum size effect and macroscopic quantum tunneling effect of nanoparticles provide new ideas and approaches for the design and preparation of high-performance and multi-functional new materials.