Trisegment composite initiator for synthesizing super high molecular weight polyacrylamide

Abstract

The invention discloses a three-segmented composite initiator of super-molecular weight polyacrylamide, which is characterized by the following: three-segmented initiator system is composed of reacting speed control agent, solutizer, one-segmented, two-segmented, three-segmented initiator according to certain proportioning; the polyacrylamide with over 25,000 thousand molecular weight can be synthesized stably in the industrial manufacturing, whose reacting speed can be controlled effectively.

Description

technical field [0001] The invention relates to a three-stage composite initiator for synthesizing ultrahigh molecular weight polyacrylamide. Background technique [0002] The free radical polymerization theory shows that the chain length is inversely proportional to the square root of the initiator concentration, the average degree of polymerization is directly proportional to the kinetic chain length, and the amount of the initiator has a significant impact on the average molecular weight of the polymer. The use of low-activity initiators can reduce the polymerization reaction speed. The polyacrylamide product has a large relative molecular mass, but the activity of the initiator is too low, too few free radicals are generated, and there are few active points for initiating monomer polymerization. Polymerization cannot be fully initiated, and some molecular chains in the polymer will grow excessively, which may increase the probability of mutual reaction and entanglement b...

AI Technical Summary

Problems solved by technology

In the traditional polymerization initiation system, the reactivity of the initiator is low, and it is difficult to initiate polymerization when the temperature is lower than 15°C

When the temperature rises, although it can be initiated normally, the reaction speed is too fast, and the concentration of free radicals increases rapidly, making the polymerization reaction speed difficult to control

However, the initiator used has a high decomposition temperature and a fast decomposition speed, resulting in an excessively fast polymerization speed.

Especially in the later stage of the polymerization reaction, as the polymerization reaction releases a large amount of heat, the temperature of the reaction system rises sharply, which accelerates the decomposition speed of the initiator and makes it difficult to control the polymerization reaction speed.

In addition, some initiators are insoluble or slightly soluble in water, which makes them unable to be evenly distributed in the reaction system. During the polymerization reaction, the local initiator concentration will be too high and the reaction will be too fast.

At the same time, some initiators are greatly affected by the acid-base environment, resulting in unsatisfactory reactions or even no reaction.

The initiator currently used is a high-temperature and strong initiator, which restricts the reduction of the initial polymerization temperature, and the reaction speed is too fast to be controlled. This is considered to be an important reason for affecting the molecular weight of polyacrylamide.

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