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Method for preparing high molecular weight polyacrylamide dried powder

A polyacrylamide and high molecular weight technology, applied in the field of preparation of polyacrylamide dry powder, can solve the problems of high amount of free monomers, uneven foaming, affecting product quality, etc.

Inactive Publication Date: 2004-11-03
许振举
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Some systems also add foaming agent, but the foaming is not uniform, which affects the product quality
The molecular weight of polyacrylamide can be increased by photopolymerization, but the amount of free monomers in the product is high, and the polymerization is not complete, which also affects the quality of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Weigh 1000kg 30% aqueous solution of acrylamide monomer in an enamel reaction kettle, start stirring, add 45kg sodium carbonate and 45kg sodium bicarbonate, add 15kg urea, 30kg ammonium bicarbonate, 0.3kg azobisisobutyronitrile, make the temperature Raise to 30°C, stir and dissolve for 1 hour, blow in nitrogen for 15-30 minutes, put 500ppm ammonium persulfate and sodium sulfite each, once the polymerization becomes sticky, immediately put the materials into the polymerization tank (for ease of operation, to prevent the polymerization of products is not easy Take it out from the reaction kettle), after 3 to 4 hours, the polymerization is completed, pour out the obtained spongy rubber block, cut it, and grind it into granules with a grinder, dry it at 70 to 90°C for 4 to 6 hours, and pulverize Then get dry powder. Molecular weight Mw=21.66 million, [η]=25.9, no insoluble matter.

Embodiment 2

[0022] The process is the same as in Example 1, hydrolyzing agent sodium carbonate 6kg, sodium bicarbonate 54kg; urea 9kg; blowing agent ammonium bicarbonate 36kg; high temperature initiator azobisisobutyronitrile 0.6kg; ammonium persulfate and sodium sulfite each 300ppm.

[0023] Molecular weight Mw=22.3 million, [η]=26.4, free monomer content≤0.03%.

Embodiment 3

[0025] The process is the same as in Example 1, hydrolyzing agent sodium carbonate 60kg, sodium bicarbonate 30kg; urea 12kg; blowing agent ammonium carbonate 45kg; high temperature initiator azobisisobutyronitrile 1.5kg; ammonium persulfate and sodium sulfite each 400ppm.

[0026] Molecular weight Mw=21.91 million, [η]=26.1, free monomer content≤0.03%.

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PUM

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Abstract

The preparation of high molecular weight polyacrylamide powder is one low temperature aqua polymerization process, and compared with available technology, the present invention is different in that it adopts the mixture of sodium bicarbonate and sodium carbonate as hydrolyzing agent, the added foaming agent, and trinary initiator system comprising high temperature initiator added before reaction and oxidation-reduction initiator added after the system temperature is controlled in 10-40 deg.c. The polyacrylamide product of the present invention has the advantages of high molecular sieve of 18-23 million, solid content of about 90 %, characteristic viscosity not lower than 23 dl / g, high water solubility, free monomer less than 0.03 % and hydrolysis degree of 20-30 %.

Description

technical field [0001] The invention relates to a preparation method of polyacrylamide dry powder. Background technique [0002] The preparation method of polyacrylamide generally adopts the aqueous solution polymerization method. The aqueous solution of monomer acrylamide dissolves the hydrolyzing agent evenly, passes through nitrogen to remove the oxygen in the system, and then adds an oxidation-reduction initiator to carry out the polymerization reaction at a temperature of 10-40°C. . In order to increase water solubility, urea can also be added. The required hydrolyzing agent adopts sodium carbonate. The current preparation method is according to the common formula [η]=3.73×10 -4 The molecular weight Mw of polyacrylamide dry powder calculated by Mw is lower than 18 million. Some systems also add foaming agent, but the foaming is uneven, which affects the product quality. The molecular weight of polyacrylamide can be increased by photopo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F6/00C08F120/56
Inventor 许振举薛秀英许广玉
Owner 许振举
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