Temperature-Responsive Polymers

Chapter 5 Sodium Alginate Grafted with Poly(N‐isopropylacrylamide)

Catalina N. Cheaburu‐Yilmaz¹, Cornelia Vasile¹, Oana‐Nicoleta Ciocoiu², and Georgios Staikos²

¹Department of Physical Chemistry of Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Romanian Academy, Iasi, 700487, Romania

²Department of Chemical Engineering, University of Patras, 26504 Patras, Greece

5.1 Alginic Acid

Alginic acid, a polyuronide, is an algal polysaccharide found in seaweeds. Pure alginic acid was first prepared in 1896, and in 1929 Kelco Company (a division of Merck, Inc.) began commercial production of alginates in the United States and introduced milk‐soluble alginate as an ice cream stabilizer [1]. Furthermore, its unique physical properties enable it to be used as a viscosifier and gelling agent in food and beverage, paper and printing, biomaterials, and pharmaceutical industries. It attracts a broad research interest, owing to its biocompatibility and biodegradability. At the middle of the nineteenth century, it was discovered that strains of Pseudomonas aeruginosa and Azotobacter vinelandii elaborate extracellular polyuronides that closely resemble alginic acid, recovered from the brown algae [2].

Alginate is a water‐soluble linear polysaccharide, the only polysaccharide that naturally contains carboxyl groups in each constituent residue, and possesses various abilities for functional materials. Alginic acid has an anionic nature, forming alginate salts with cations, ...