Propriétés rhéologiques à l'état fondu de mélanges binaires de polyéthylène et de polybutène-1

The dynamic rheological study on a series of binary blends obtained from low-density polyethylene and poly(1-butene) was carried out. From our results we can propose an analogical pattern which is able to simulate the rheological behaviour of the blend in the melt state. We have calculated the different parameters of the model and their variations with temperature, composition, mixing and frequency. We have demonstrated that:

• The viscosity η₀ and the mean relaxation time τ₀ decrease with increasing temperature, while the parameter h of the distribution of relaxation times remains independant of the temperature.
• Kneading operation gives rise to a drop of the τ₀, η₀ and h values compared to those products which have not been kneaded.
• The viscosity η₀ is the weighted sum of the blend components.
• The viscosity η₀ of the blend is a function of the molecular weight.