Chitosan Hydrogels Based on the Diels–Alder Click Reaction: Rheological and Kinetic Study

Polymers

Carlos Peniche-Covas¹  Waldo Argüelles-Monal²  Luisa Silva-Gutiérrez²  Jaime Lizardi-Mendoza²  Cinthya Ruiz-Pardo²  Yolanda López-Franco² 

[1] Facultad de Química, Universidad de la Habana, Vedado, La Habana 10400, Cuba;Grupo de Investigación en Biopolímeros, Centro de Investigación en Alimentación y Desarrollo A.C., Hermosillo 83304, Sonora, Mexico;

关键词: click chemistry;    Diels–Alder reaction;    chitosan;    PEG-maleimide;    furan;    rheology;   

DOI  :  10.3390/polym14061202

来源: DOAJ

【 摘 要 】

The Diels–Alder reaction is recognized to generate highly selective and regiospecific cycloadducts. In this study, we carried out a rheological and kinetic study of N-furfuryl chitosan hydrogels based on the Diels–Alder click reaction with different poly(ethylene)glycol-maleimide derivatives in dilute aqueous acidic solutions. It was possible to prepare clear and transparent hydrogels with excellent mechanical properties. Applying the Winter and Chambon criterion the gel times were estimated at different temperatures, and the activation energy was calculated. The higher the temperature of gelation, the higher the reaction rate. The crosslinking density and the elastic properties seem to be controlled by the diffusion of the polymer segments, rather than by the kinetics of the reaction. An increase in the concentration of any of the two functional groups is accompanied by a higher crosslinking density regardless maleimide:furan molar ratio. The hydrogel showed an improvement in their mechanical properties as the temperature increases up to 70 °C. Above that, there is a drop in G’ values indicating that there is a process opposing to the Diels–Alder reaction, most likely the retro-Diels–Alder.

【 授权许可】

Unknown