0.1%-0.3% of the total weight of the final product when used as a fungicide in the paper industry, as an additive in paper mills and for the preservation of bulk pulp.
The recommended dosage is 0.5%-1.0% of the system water volume when used in the pulp mixing tank, pulp making tank, high level overflow tank, thickener and white water tank before pulp loading.
The coating industry also often uses free radical initiators in the film forming process. For example, some unsaturated polyesters are polymerized by free radicals and crosslinked to form a film. The film formation process is often carried out at room temperature and requires a low temperature initiation system.
Selection and use of initiators in solution polymerization
The polymerization reaction in which the monomer and initiator are dissolved in a solvent is called solution polymerization. Therefore, the initiator must be dissolved in the solvent mpi micronized wax and the monomer, and an organic solvent is generally used.
Under normal pressure, the temperature of solution polymerization is always close to the boiling temperature of the solvent, and polymerization is often performed at the reflux temperature of the solvent. Because the reaction temperature is easy to control when the solvent is refluxed. When the reaction is violent, the heat released accelerates the reflux of the solvent and quickly takes away the heat, so that the reaction temperature remains stable. Of course, when the polymerization reaction is slow, it can also be polymerized at a temperature lower than the boiling point of the solvent. Therefore, the solvent polymerization reaction temperature can vary from 60 to 200 ℃ in a wide range, and the initiators that can be used far exceed those mentioned above. Due to the high polymerization temperature, the redox initiation system is rarely used. In addition to factors such as supply, price, toxicity, storage stability and ease of operation, the following factors should be considered when selecting initiators.
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