A study on yield behavior and stress relaxation of α-Gels

α gels are used in variety industrial fields and exhibit a very complex yield behavior. After the macroscopic structure has been destroyed by flow, it recovers and the gels exhibit yield behavior again at a certain time later. The restructuring process is examined by the stress relaxation experiment after the stress ramp test. From the temporal response of the stress relaxation process, the relaxation process can be divided into two regions by the short or long term behavior. The four elements Maxwell model was applied and two relaxation times are evaluated. The long term relaxation time is not affected by the condition before the relaxation. On the other hand, the short term relaxation shows a non-linear behavior when the flow is stopped at the region C that is just before the second yield point.