SU443878A1 - The method of obtaining grafted copolymers of polyacrylamide - Google Patents

Description

one

The invention relates to the field of modification of polyacrylamide and the preparation of graft copolymers.

A known method for producing grafted polyacrylamide copolymers by polymerizing vinyl monomers in an aqueous solution of polyacrylamide containing a radical initiator.

However, the effectiveness of irivivka in this case is not high enough.

To increase the efficiency of irivivka, it is proposed to carry out the process in an environment of water and an organic solvent that is miscible with it, at a ratio of the components of the mixture that ensure the dissolution of polyacrylamide.

The amount of organic solvent may vary within certain limits, which depend on its nature.

As organic solvents, those which do not dissolve the acacrylamide: alcohols, acetone, dioxane and others can be used. Thus, the reaction is carried out in a medium that is a poor solvent of Polyacrylamide.

The lower limit of the introduced organic solvent is the minimum that already provides a significant increase in the efficiency of the grafting, the upper one is the maximum of the solvent, at which the acacrylamide remains in solution.

For example, the content of isopropyl alcohol in a mixture can vary from 7.5 to 25%, the best results are obtained at 12-15%. The ethanol content can vary from 10 to 40%; the best results are obtained at 20-30%. For methyl alcohol, the permissible administration limits are 15-50%, preferably 25-40%, for acetone 7.5-20%, preferably 10-15%.

According to the proposed method, the reaction is carried out as follows: M.

A water-soluble organic solvent (ethyl alcohol, isopropyl alcohol, acetone) is added to the aqueous solution of polyacrylamide. To prevent polyacrylamide from falling out of solution, the solvent can be pre-diluted with water to 70-50% concentration or carried out

add solvent slowly and with vigorous stirring. The monomer, a polymerization initiator, is added to the aqueous organic solution of polyacrylamide and the reaction mixture is heated while stirring.

to 80-90 ° C (until the end of the reaction).

As a result of the reaction, homogeneous, very white-white dispersions of copolymers are formed. Under the conditions described, a grafting efficiency of 0.60-0.90 is achieved, which is significantly higher than with the conventional graft copolymerization method.

Depending on which graft monomer is used for grafting, the solimerizers can be used as fiber-forming, film-forming agents and for other purposes.

Example 1. In a three-necked flask with a stirrer and reflux condenser load 54.5 weight. including aqueous 2.75% solution of polyacrylamide and with vigorous stirring a mixture of isopropyl alcohol (28 parts by weight) and distilled water (99 parts by weight), 1.1% by weight is slowly added. including 25% ammonium hydroxide, 0.135 weight. including ammonium persulfate n 6 wt. including freshly distilled methyl acrylate. The reaction mixture is heated in a water bath to 80-90 ° C and stirred at this temperature until the end of the polymerization (40-60 minutes). The effectiveness of vaccinations 0.79.

Example 2. In a three-necked flask with a stirrer and reflux condenser load 54.5 weight. including aqueous 2.75% polyacrylamide solution and with vigorous stirring a mixture of ethyl alcohol (61.6 wt. parts) and distilled water (65.4 parts by weight), 1.1 wt. including 25% ammonium hydroxide, 0.135 weight. including ammonium persulfate and 6 wt. including freshly distilled methyl acrylate. The reaction mixture is heated in a water bath to 80-90 ° C and stirred

at this temperature until the end of the polymerization (40-60 min). The effectiveness of vaccinations 0.90. Example 3. The flask is loaded 54,5

weight. including aqueous 2.75% polyacrylamide solution and with vigorous stirring a mixture of acetone (18.7 parts by weight) and distilled water (108.3 parts by weight), 1.1 weight. including 25% ammonium hydroxide, 0.135

weight. including a-mmoni persulfate and 6 wt. including freshly distilled methyl acrylate. The reaction mixture is heated to 80-90 ° C and stirred at this temperature until the end of the polymerization (40-60 minutes). Efficiency

vaccinations 0.6.

Subject invention

The method of obtaining polyacrylamide grafted from polymers by polymerizing vinyl monomers in a solution of polyacrylamide containing a radical initiator, when heated, is distinguished by the fact that, in order to increase the efficiency of irivivka, a mixture of water and an organic solvent mixed with it is used, with a mixture ratio of the mixture components , ensuring the dissolution of polyacrylamide.