Flow behavior of partially crosslinked low-density polyethylene

The viscosity of low-density crosslinked polyethylene was studied as a function of gel content and shear rate (3.75–33 sec^?1). A simple model relating viscosity with gel content is suggested. It is shown that sol viscosity decreases with cross-linking propagation. The rheological parameters of the sol fraction are changed as a result, and it is natural that this effect should be utilized for flow calculations. Experimental data indicate a high degree of interaction between the sol molecules and the gel, and an experimental technique is presented for measuring it. The rheological parameters of crosslinked polyethylene are closely dependent on the gel content, viscosity and pseudoplasticity increasing with the latter.