Strength‐time Relationships of Agar and Alginate Gels 1

The compressive strength of 2% agar and alginate gels was monitored periodically during the first 50–80 h after preparation. The strength increased rapidly in the first 6 h in the former and about 15 h in the latter, and then tended to stabilize, asymptotically. An empirical, two parameter mathematical model was used to estimate the asymptotic value on the basis of data obtained during the first 8 or 20 h, respectively. The common procedure of testing these gels after 24 h is satisfactory, since changes after this time are relatively small. A similar two parameter model was also applied to the weight loss of the alginate gels and it enabled prediction of the gel's final weight with reasonable accuracy. Since both models can be presented in a linear form, testing their applicability and calculation of their constants can be done by linear regression.