Photocrosslinking of partially cinnamoylated poly(vinyl alcohol)/poly(vinyl acetate) copolymer in aqueous solution

✍ Scribed by Heikki Tenhu; Jutta Nuortila-Jokinen; Franciska Sundholm

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 454 KB
• Volume: 24
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(88)90040-7

✦ Synopsis

A photocrosslinkable water-soluble polymer has been prepared by partial esterification of poly(vinyl acetate-co-vinyl alcohol) with cinnamic acid. The photochemical [2 + 2] cycloaddition reaction has been used as a chemical probe for the investigation of different conformational states of the polymer chain in aqueous solution. At around 20 °, the polymer adopts a compressed conformation with the hydrophobic side-groups turned out from the coil, this conformation leading to intercatenary crosslinki~ig during irradiation. At temperatures lower or higher than 20 °, the polymer coil expands; the intercatenary reaction is no longer dominant. The dynamics of the polymer in solution, as well as the interaction between water molecules and the polymer, have been studied with nitroxide sonds and calorimetrically. Crosslinking is shown to prevent the conformational change detected in the parent polymer around 20°; crosslinking also affects the water-polymer interaction.