Viscosity and mixing behavior of the system ethylene—polyisobutylene

Abstract

Two samples of polyisobutylene LPIB 3.9 with M w = 3.9 kg mol -1 and M w M n =1.30 ; and PlB 1.4 with M w = 1.40 kg mol − and M w M n = 1.56 ) were obtained by means of continuous polymer fractionation. The minimum pressures required to achieve complete miscibility of these polymers with etyylene (Et) in the temperature range from 30 to 70 °C are on the order of 200 to 500 bar. The zero shear viscosities of the mixtures are in all cases found to be less than the values calculated from the additivity of η 0 of the components in terms of volume fractions. The transition of the activation energies and activation volumes from the low values for Et (5 kJ mol − and 6 cm 3 mol −1) to the large values for PIB (55 kJ mol −1 and 80 cm 3 mol −1) with increasing polymer content takes place in a pronounced sigmoidal manner.