POLYMER-CHAIN CONFORMATION IN THE MELT DURING STEADY ELONGATIONAL FLOW AS MEASURED BY SANS - TEMPORARY NETWORK MODEL

The anisotropic form factor of a polymer sample with narrow molecular weight distribution was measured during simple elongational flow in the molten state. The strain rate range investigated corresponded to the linear viscoelastic regime for this polymer system, which allowed the experimental results to be checked in steady-state flow, and the reliability of the measurements to be assessed. It has been shown that a previously discussed relationship between tensile stress and recoverable strain allows the form factor of the chains to be calculated from only two physically meaningful parameters: the macroscopic recoverable strain and the number of submolecules between entanglements per chain. The agreement between the model and the experimental data is satisfactory in the molecular and submolecular scattering vector domain. © 1990, American Chemical Society. All rights reserved.