General Plastics in Engineering Modification
General plastics are widely used in life, such as PE,PP in packaging, automobiles, daily necessities sundries, etc., PS in the light industry market, electrical industry, etc., PVC in packaging, pipes, etc. But at the same time, it also has a fatal weakness. It is easy to decompose and burn at high temperatures. At the same time, a large amount of smoke and toxic and harmful gases are generated during the combustion process, which causes great harm to the ecological environment and people's health.
In order to protect the natural ecology and human health, the flame retardant problem of polymer materials is waiting for people to solve, in-depth research on the mechanism of flame retardant and the development and expansion of new flame retardants are of great significance to the harmonious development of society.
now popular general-purpose plastic flame retardants, according to the relationship between flame retardants and flame retardants, flame retardants can be divided into two categories: additive and reactive, and most of the applications are divided into two ways, one is physically dispersed in the substrate, mostly used in thermoplastic polymers. The second is as a monomer, or auxiliary reagents to participate in the synthesis of polymer reaction, and finally become the structural unit of the polymer, more for thermosetting polymers.
According to the types of flame retardant elements, commonly used flame retardants are often divided into halogen series, organic phosphorus series and halogen-phosphorus series, nitrogen series, phosphorus-nitrogen series, antimony series, aluminum-magnesium series, inorganic phosphorus series, boron series, silicon series, molybdenum series, etc. There is also a class of intumescent flame retardants (most of them are complexes of phosphorus-nitrogen compounds) and a nano inorganic substance (mainly layered silicate), the latter can be composed of a series of high polymer/inorganic nano composite materials with flame retardant.
halogen flame retardant is one of the largest chemical flame retardants in the world. Although halogen flame retardants produce more smoke and corrosive gases during thermal cracking or combustion, they currently occupy the dominant position of plastic flame retardants. The reason why halogen flame retardants are valued by people is mainly because of their high flame retardant efficiency and moderate price, and their performance/price ratio index is difficult to compare with other flame retardants. In addition, there are many varieties of halogen flame retardants and a wide range of applications, so they are favored by people. When halogen flame retardants are used alone, they mainly alleviate or prevent the combustion of polymers in the gas phase.
phosphorus flame retardant is one of the most important varieties of flame retardant, phosphorus flame retardant is not a new type of flame retardant, but he as a halogen-free system, in the field of flame retardant is very remarkable. It has the dual function of flame retardant and plasticizing. Its plasticizing function can make the plastic molding flow processability becomes better, can inhibit the residue after combustion. The generation of toxic gases and corrosive gases is less than that of halogen-based flame retardants.
the best flame retardant is inorganic flame retardant. It has good thermal stability, low toxicity or non-toxic, does not produce corrosive gases, does not volatilize, does not separate hair, flame retardant effect for a long time, rich and diverse sources of raw materials, low prices and other advantages.
