Dynamic rheological analysis storage modulus

Another possibility of determining the gel point with the help of rheological methods is dynamical mechanical spectroscopy. Analysis of change of dynamic mechanical properties of reactive systems shows that the gel point time may be reached when tan S or loss modulus G" pass a miximum [3,4,13], Some authors proposed to correlate the gel point with the intersection point of the curves of storage and loss moduli, i.e., with the moment at which tan 5 = 1 [14-16], However, theoretical calculations have shown that the intersection point of storage modulus and loss modulus meets the gelation conditions only for a certain law of relaxation behavior of the material and the coincidence erf the moment of equality G = G" with the gel point is a particular case [17]. The variation of the viscosity... 

Dynamic mechanical analysis (DMA) is a suitable technique that allows the characterisation of the solid-state rheological behaviour of materials, including biomaterials , in a broad temperature and frequency ranges. Specifically, this technique has been used in the characterisation of bone cements or hydrogels ". Such materials display usually an anelastic behaviour and DMA is able to monitor the complex mechanical modulus (E = E + E where E" is the storage modulus and E is the loss modulus, and the complex compliance (D - D - iD ). The loss factor, tan 6 = EVE = D D , measure the damping capability of the material. 

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