In the course of operating, free radical initiators mainly refer to reagents that generate free radicals in free radical reactions. To a certain extent, free radical initiators can be effectively called. In the course of carrying out the reaction, radicals are mainly generated. The process becomes chain initiation.
The bond breaking energy of the compound of the radical initiator is between 104.5 and 167.2 kJ/mol, and the heating temperature during the operation is 50 to 150° C. The free radical initiator that is commonly used during the use process will have t Hydrogen peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, and the like.
Free radical initiator decomposition rate constant
In operation, at a certain temperature, the polymerization rate of the monomer depends to a large extent on the decomposition rate of the initiator, which is directly proportional to the initiator concentration. Ethyl acetate can significantly promote persulfuric acid. In the decomposition reaction of the acid salt, the decomposition rate constant increases from 0.248 h-1 to 2.08 h-1 at 80°C.
The free radical initiator of methanol will also have a great impact on the decomposition of persulfate to a certain extent, the decomposition rate will increase 25 times, and the emulsifier sodium lauryl sulfate also significantly promote the decomposition of persulfate. .
The active oxygen content, also called effective oxygen content, represents the amount of free radicals produced by the decomposition of a certain mass of peroxide.
The free radical initiator mainly refers to the lowest temperature when the peroxide decomposes radicals generated by heat. The critical temperature and the decomposition temperature are slightly different during the operation, and the decomposition temperature is the peroxide half-life during use. At a temperature of 10 h, the critical temperature of the peroxide as an initiator is mostly 60-130° C. If it is lower than 60° C., the room temperature is very unstable and is not suitable as an initiator.
Free radical initiator activation energy
The activation energy is, to a certain extent, a very important factor that determines the decomposition rate of the initiator, which is determined based on its empirical formula to a certain extent. The activation energy is large, the initiator is not easily decomposed, but it is relatively stable; the activation energy is small, and it easily decomposes to generate free radicals.
The initiator's decomposition rate constant, half-life, and decomposition activation energy can be used as the basis for selecting the initiator, polymerization temperature, and production cycle. Connected to release the amount of expansion water.