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Six Ways to Improve the Flame Retardant Effect
01、Surface Modification
Inorganic flame retardants have strong polarity and hydrophilicity, poor compatibility with non-polar polymer materials, and it is difficult to form a good 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. Commonly used coupling agents are silane and titanate esters. For example, after silane treatment of alumina hydroxide (ATH) flame retardant effect is good, can effectively improve the bending strength of polyester and epoxy resin tensile strength; ATH treated with ethylene-silane can be used to improve the flame retardant, heat resistance and moisture resistance of crosslinked ethylene-vinyl acetate copolymers. Titanate coupling agent and silane coupling agent can be used together to produce synergistic effect. After surface modification, the surface activity of ATH is improved, the affinity between ATH and resin is enhanced, the physical and mechanical properties of the product are improved, the processing fluidity of the resin is increased, the moisture absorption rate of ATH surface is reduced, the electrical properties of ATH surface are improved, and the flame retardant effect is increased from V-1 grade to V-0 grade.
02、Ultrafine
Inorganic flame retardants are more and more popular because of their high stability, low volatilization, low toxicity and low cost. However, its compatibility with synthetic materials is poor, and the large amount of additive reduces the mechanical properties and heat resistance of the materials. Therefore, it is one of the developing trends of inorganic flame retardants to modify inorganic flame retardants with superrefinement to enhance their compatibility with synthetic materials and reduce their dosage. For example, ATH's ultra-refinement and nanocrystallization are the main research and development directions to improve its flame retardant effect. A large number of ATH additions will reduce the mechanical properties of the material, but by fining ATH and then filling it, it will have the effect of plasticizing and strengthening rigid particles, especially nanoscale materials. Because the flame retardant function is dominated by chemical reaction, the smaller the particle size of the same amount of flame retardant is, the larger the specific surface area is, and the better the flame retardant effect is. Hyperrefinement is also an affinity consideration. It is the polarity difference between ATH and polymer that leads to the degradation of the physical and mechanical properties of the flame retardant composites. The superfine and nano-sized ATH enhanced the interfacial interaction and dispersed evenly in the matrix resin, which improved the mechanical properties of the blend more effectively.
03 Compound Synergy
In practical production and application, a single flame retardant always has some defects, and it is difficult to meet the higher and higher requirements with a single flame retardant. The compounding technology of flame retardants is to compound phosphorus, halogen, nitrogen and inorganic flame retardants among or within certain kinds of flame retardants to seek the best economic and social benefits. Flame retardant compounding technology can integrate the advantages of two or more kinds of flame retardants to make their performance complementary, so as to reduce the amount of flame retardants, improve the flame retardant properties, machining properties and physical and mechanical properties of materials.
04 Cross linking
Crosslinked polymers have much better flame retardancy than linear polymers. Adding a small amount of crosslinking agent in thermoplastic processing can make the plastic become part of the network structure, can improve the dispersity of flame retardant agent, is conducive to the combustion of plastic carbon, improve the flame retardant performance, and can improve the mechanical and heat resistance properties of products.
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 materials to form microencapsulated flame retardants, or take inorganic materials with a large surface as the carrier, adsorb flame retardants in the space of these inorganic materials to form honeycomb microencapsulated flame retardants. The microencapsulation of bromine environmental retardant has the following advantages: it can improve the stability of flame retardant; It can improve the compatibility of flame retardant and resin, so that the phenomenon of physical and mechanical properties of the material can be improved. It can greatly improve the performance of flame retardant and expand its application range.
06 Nano flame retardant
Some nanomaterials have the function of preventing combustion, and when they are added into combustible materials as flame retardants, their special size and structure effects can be used to change the combustion performance of combustible materials and make them become fire-resistant materials. Nano - technology can change the flame - retardant mechanism and improve the flame - retardant performance. Due to the small particle 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 multifunctional new materials.
