Rheological characteristics and magnetization effects of magnetic gels

Magneto-rheological effects of K-carrageenan magnetic gels have been investigated. The magnetic gel was made of a natural polymer of K-carrageenan and a ferromagnetic particle of barium ferrite. The complex modulus of the magnetic gel was measured by dynamic viscoelastic measurements with a compressional strain. It was observed that the magnetic gels showed giant storage modulus reduction similar to 10MPa before and after magnetization. The reduction increased with increasing the volume fraction of the ferrite and it reached 14.9 MPa at maximum. No volume change was observed during magnetization. Strain and frequency dependences of the dynamic modulus and a possible mechanism of the modulus reduction have been discussed.