Principle of Micellar Polymerization of Acrylamide

Acrylamide is a widely used chemical raw material in the industrial field. It is a recognized neurotoxin and a possible human carcinogen. Acrylamide is a hard glassy solid at room temperature. The products include glue liquid, latex, white powder particles, translucent beads and flakes. It has high thermal stability. It can be dissolved in water in any proportion, and the aqueous solution is a uniform and transparent liquid. After long-term storage, the solution viscosity will decrease due to the slow degradation of the polymer, especially at poor storage and transportation conditions.

Ⅰ. Formation mechanism of acrylamide

Acrylamide does not exist in natural food ingredients, but raw materials rich in reducing sugar and aspartic acid will produce acrylamide in Maillard reaction after high-temperature processing; therefore, planty raw materials such as potatoes, Cereals, etc. are easier to produce acrylamide during thermal processing than animal raw materials.Food like fried potato products, soft bread breakfast cereals, biscuits, coffee and infant foods are all contain high degree acrylamide. Acrylamide uses is board in food and chemical industry.

As a tupe of common chemical compounds the formation of acrylamide is a very complex process. In the initial stage of Maillard reaction, reducing sugar and asparagine form Schiff base through addition reaction under non enzymatic conditions, and unstable Schiff base can further form acrylamide through dehydrogenation, oxidation and rearrangement.

In addition to the asparagine pathway, there are other ways to form acrylamide. It includes the recombination of small molecular aldehydes, the degradation of amino acids, the thermal decomposition of oils and fats, etc.

Ⅱ. Principle of micellar polymerization of acrylamide

Micellar copolymerization is a common method to prepare hydrophobically modified water-soluble polymers. Because the hydrophobic monomer is water-insoluble, the hydrophobic monomer is usually solubilized in water by adding appropriate amount of surfactants in water, and copolymers with water-soluble monomers are different from homogeneous solution polymerization, emulsion or microemulsion polymerization. It is a kind of micro heterogeneous polymerization system. The reaction process is as follows:

1. The water-soluble initiator decomposes into free radicals in the aqueous phase to initiate the polymerization of acrylamide.

2. When the growing acrylamide radical collides with the solubilized micelles of dissolved hydrophobic monomers and initiates the polymerization of hydrophobic monomers in the micelles, a small hydrophobic segment is introduced into the hydrophilic polymer chain.

3. Macromolecular free radicals leave the micelle and continue to react with acrylamide, directly encounter another solubilized micelle and reintroduce a small hydrophobic segment.

3. Because the average life of acrylamide radical is long, the above process is repeated until the macromolecular radical is terminated.