Creep of glutaraldehyde-crosslinked gelatin films

Creep behavior of glutaraldehyde-crosslinked gelatin films was evaluated by short-time flexural tests at 30 °C. Samples were characterized by the number-average molecular weight between two crosslinking points, determined by using the Flory–Renher equation. Creep response decreased with increasing degree of crosslinking, which is an indication that crosslinking improves the film stiffness. Experimental creep data were compared with calculated ones by using two different approaches, the creep power-law and the four-parameters model. Good fitting of the experimental results with both models was found, leading to a relationship between the observed creep behavior and the structure of the crosslinked gelatin films. Chemical crosslinkages seemed to induce a decrease of the viscous creep and an enhancement of the elastic contribution.