Water-absorbent polymer structures based on renewable resources and method for producing said structures

A process of producing a polymer by radical polymerization of acrylic acid, comprising the steps of:

• A) forming β-hydroxypropionic acid by splitting an organic material comprising a carbohydrate in the presence of a microorganism and a nutrient solution comprising carbon sources, nitrogen sources, and salts thereof for the nutrition of the microorganism, by means of an enzyme or at least one component of an enzyme;
• B) purifying the product of step A) including the step of removing the β-hydroxypropionic acid from the nutrient solution to provide β-hydroxypropionic acid;
• C) dehydrating the β-hydroxypropionic acid of step B) to form an aqueous acrylic acid solution;
• D) purifying the aqueous acrylic acid solution of step C) by crystallization to have a benzaldehyde content of less 0.1 ppm, a maleic acid or maleic acid anhydride content of less than about 5 ppm, an acetic acid content of less than 0.1 ppm and a ketone content of less than about 5 ppm, wherein the purification includes removal of water from the aqueous acrylic acid solution to form acrylic acid;
• and
• E) polymerizing the acrylic acid of step D) by radical polymerization to produce the polymer.