Bromine is a deep reddish brown liquid, a non-metallic element at room temperature, an important chemical raw material, and can be used in flame retardants. Below, the bromine manufacturer's editor will introduce the role of bromine in bromine based flame retardants.
Firstly, let's talk about the role of flame retardants. Many products nowadays are made of polymer materials, which are flammable. Therefore, flame retardants that prevent combustion must be added in manufacturing. Flame retardants are divided into two categories based on their usage: reactive and additive.
Reactive flame retardants participate as a component in the synthesis of polymer materials and are mainly used in thermosetting plastics; Additive flame retardants are added during processing and molding, and are simply mixed with polymers. Generally, they are used for thermoplastic plastics. At present, the plastic varieties that consume more flame retardants are polyurethane foam, PVC, polystyrene, polyester and polyolefin. Bromine in halogens can be used as a raw material for flame retardants to produce both additive and reactive flame retardants.
Brominated hydrocarbon flame retardants have stronger heat resistance than chlorinated hydrocarbon flame retardants and are less prone to thermal decomposition during resin processing. They are G-effect flame retardants and are generally added in small amounts, with little impact on the processing and usage properties of polymers. They can be used for polystyrene, ABS resin, polyurethane resin, epoxy resin, polyolefin, and certain polyurethane resins. Especially in recent years, with the development of industry and the improvement of people's living standards, the demand for G-grade plastic resin products has increased significantly, and the amount of G-effect flame retardants is also increasing. The research and development of G-effect bromine flame retardants are gradually becoming active.
So what is the flame retardant mechanism of using bromine raw materials to manufacture flame retardants?
The addition of flame retardants can control the dispersion of combustion heat energy; Can isolate flammable plastics from air; It can dilute the combustible gases produced by plastic decomposition or cut off the HO · free radical chain reaction during combustion.
HO · radicals have high energy and fast reaction speed, so the degree of combustion is determined by the proliferation of HO · radicals. When containing halogen flame retardants, hydrogen halides (HX) will decompose at high temperatures, and hydrogen halides can capture and convert high-energy H0 · radicals generated during combustion into low-energy halogen radicals x · and H20. At the same time, halogen radicals x · react with hydrocarbons to generate HX, and this cycle will cut off the chain reaction of free radicals.
The activation energy of hydrogen bromide reaction is relatively low, so a small amount of ship r may compete with fuel for high-energy free radicals to generate low activation energy Br ·, which plays a role in flame suppression. In addition, the generated bromine atoms can further react with hydroxyl groups to regenerate HBr, playing a role in flame suppression.
The addition of bromide reduces the concentration of H · and HO ·, achieving the purpose of flame retardancy.
