Time dependent properties of thermoreversible gels

Abstract

Rheological properties of the system gelatin + water at a polymer concentration of 5.0% by wt at a temperature of 301 K and an angular frequency of 0.628 rads⁻¹ are presented and evaluated by use of the percolation theory. A frequency power law has been found close to the gel point from which a critical time range could be deduced in which the powers of the loss and storage modulus are the same. The times needed for the gelation from the percolation relations are close to the range where the exponents of the frequency power law relations are identical. The scaling coefficient Δ for physical gelation agrees very well with that found for chemical gelation by Durand and coworkers.

Keywords:

• Thermoreversible gels
• Percolation theory
• Critical exponents
• Frequency dependency