Polymer Synthesis

Synthesis of improved flocculants

The rational design of flocculation processes requires polyelectrolytes as flocculants, with high molecular weight copolymers from acrylamide and cationic acrylic esters dominating the market. Even though these copolymers give satisfying results for the majority of applications, they suffer from various drawbacks like tendency to hydrolyze, toxicity of acrylamide or level of mineral oil that can form problems in some applications. Therefore, new alternative flocculants are needed. The Fraunhofer IAP accordingly conducts the development of such products, utilizing a combination of both procedural and synthetic approaches.

For example, we successfully developed hydrolytically stable and acrylamide-free flocculants based on diallyldimethylammonium chloride (DADMAC). For the first time, polymers from DADMAC were synthesized with molar masses well above 106 g/mol. The process was already successfully transferred into pilot plant scale. These polymers show great flocculating effects even in applications where acrylic polymers cannot be used, e.g. extreme pH values or high concentration of salts as well as temperatures > 40 °C.