Viscoelastic behaviour in the molten state of low density polyethylene‐polybutene 1 blends

Abstract

The viscoelastic bchaviour in thc molten statc of low density polyethylene-polybutene I blends has been studied according to temperature, shearing stress and shearing rate. Measurements were made with a capillary viscometer for the static properties and a balance-rheometer system of Kepes for the dynamic properties. Correction of experimental data has been performed and flow activation energies at a constant shear stress determined, whilst elasticity was investigated by means of the Barus factor. Furthermore, an investigation has been performed on variations of the real u' and imaginary q" parts of the complex viscosity with regard to the pulsation frequency (I). The Cole-Cole and the Smyth representations were utilised to determine the Newtonian viscosity 'lo. the parameter of distribution of relaxation time / I and the average relaxation time i,. K q , II.OI.L/;Y: Barus factor, real and imaginary part of the complex viscosity, parameter of distribution of relaxation time, average relaxation time.