The interaction of polyvinylpyrrolidone with iodine

✍ Scribed by Jehudah Eliassaf

• Publisher: Elsevier Science
• Year: 1966
• Tongue: English
• Weight: 425 KB
• Volume: 2
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(66)90047-4

✦ Synopsis

The binding of iodine to polyvinylpyrrolidone (PVP) in aqueous potassium iodide solutions was studied potentiometrically. 1/n, the number of monomeric units of PVP binding one molecule of I2, increases with increasing temperature and decreases with increasing molecular weight of PVP and with the addition of Na2SO4. The fact that the characteristics of the adsorption isotherm are independent of the concentration of KI indicates that the adsorbed species is the tri-iodide ion; on the other hand it was shown by spectrophotometry that 12 is adsorbed on PVP also in solution in CHCI3 suggesting that molecular Iz is adsorbed. Polyacrylic acid, polymethacrylic acid, polyacrylamide and polymethacrylamide do not adsorb I2.

PVP and polyethylene glycol are precipitated by the tri-iodide ion, but not by the mono-iodide ion or by molecular iodine. A viscometric study shows that this is not the case with the other polymers mentioned above or with polyvinyl alcohol.