Structural Relaxation of Salmon Gelatin Films in the Glassy State

摘要

A spontaneous structural relaxation of salmon gelatin in the glassy state was observed by thermal and mechanical techniques. This behavior was related to a reduction in molecular mobility, as indicated by an increase in relaxation times (τ_0) and a decrease in relaxation rates estimated from the stress relaxation data. The reduction in β on ageing suggests a spreading of relaxation times occurring in the matrix. The excess in enthalpy in aged films was associated with lower-energy states as thermodynamic equilibrium was approached. This work shows that significant changes in structure can occur within a short time frame. This work will be continued using predictive models for the enthalpy data and will attempt to confirm or refute these findings. A direct comparison with gelatin from other sources, assessing the significance of biochemical structure on the kinetics associated with ageing, will also be carried out.