title: Drastic difference in porous structure of calcium alginate microspheres prepared with fresh or hydrolyzed sodium alginate.
abstract: Fresh or hydrolyzed sodium alginate was used as a material for preparing calcium alginate microspheres, and a drastic difference in porous structure was observed between them, even though the other materials and the preparation method except for the sodium alginate were exactly the same. When fresh sodium alginate was used, nonporous microspheres were obtained. In contrast, when 82-day-hydrolyzed sodium alginate, whose molecular weight became 7% of the molecular weight of the fresh sodium alginate, was used, porous microspheres with 6.5 times larger BET surface area were obtained. XPS studies indicated that the atomic ratio of Ca, the crosslinker of the alginic acid polymer, was almost the same in both cases. Therefore, the difference in porous structure was not attributed to the amount of crosslinking points, but to the low-molecular-weight compounds formed by hydrolysis, and they would work as pore-generating agents.
authors.affiliation: Department of Environmental and Energy Chemistry, Faculty of Engineering, Kogakuin University, Tokyo, Japan. akamatsu@cc.kogakuin.ac.jp
authors.forename: Kazuki
authors.initials: K
authors.lastname: Akamatsu
authors.forename: Kaho
authors.initials: K
authors.lastname: Maruyama
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Aiko
authors.initials: A
authors.lastname: Nakao
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Nakao
mesh_terms: D000464:Alginates / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006868:Hydrolysis; D008863:Microspheres; D015394:Molecular Structure; D010316:Particle Size; D016062:Porosity; D013499:Surface Properties
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid