Rheological behavior of polydimethylsiloxane/polyoxyethylene blends in the melt. Emulsion model of two viscoelastic liquids

The linear viscoelastic behavior of two‐phase polymer blends in the melt is characterized by high values of storage modulus at low frequencies and by long relaxation times. The variation of dynamic moduli with frequency could be explained with an emulsion model as developed by Oldroyd. This model allows us to take in account the viscoelastic behavior of each phase, as well as characteristic parameters of the blends like volume fraction, interfacial tension, and size of inclusions. Experimental results on polydimethylsiloxane/polyoxyethylene‐diol blends are found to be in good accordance with Oldroyd’s emulsion law. The terminal relaxation process of the blend can be assigned to the geometric relaxation of the inclusions.