The Great Myths of Rheology, Part II: Transient and Steady-State Melt Deformation: The Question of Melt Entanglement Stability

摘要: One of the most difficult problems to solve in rheology is prediction deformation melt during its “transient” conditions, i.e., before it reaches steady-state deformation. Most our present understanding concerns steady state when properties, e.g., viscosity or modulus, no longer depend on time and remain invariant. This article concerned with transient states obtained under non-linear conditions asks why sometimes takes a long for reach state, terminal τo calculated from at that temperature, crossover G′ G″ (τo = 1/ωx) indicates should relax much shorter times. In pure viscometry (at constant shear rate), behavior expected state. Questions regarding origin this are experimentally theoretically investigated debated linear low-density polyethylene (M/M e ∼200). We show steady-stat...