6533b7d2fe1ef96bd125dfd8

RESEARCH PRODUCT

Transient response in nonlinear region of molten polymers subjected to a sudden imposition of constant shear stress or constant electric field

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Experimental transient results in the nonlinear region are reported for a commercial polyisobutylene subjected to sudden imposition of either a constant shear stress or a constant electric field. Some steady-state results, eventually obtained in different types of experiments, are also considered. In both cases, a model analysis is presented that accounts for the nonlinear effects through changes in the free volume depending upon the applied stress. The good comparison between theoretical predictions and experimental results seems to indicate that the phenomenological approach advanced here is very promising.