The data treatment in viscosity measurement by tensile creep method was discussed. A method which may be used for polymer samples with high viscosity and low modulus was proposed. The measurements of two poly-cis-1

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butadiene samples showed that due to the difficulty to avoid wholly the influence of elastic deformation during the creep process of these samples

the previous method which was based on the assumption of the establishment of a pure steady flow state would deviate the viscosity values to one order of magnitude lower.