Dissipative Particle Dynamics and Flory-Huggins Theories for Predicting the Rheological Behavior of Ultrahigh Molecular Weight Polyethylene Blends
Résumé
This work aims to experimentally and theoretically study the effects of normal molecular weight polymers (NMWP) such as high-density polyethylene, low-density polyethylene, and polypropylene as processing aids on the morphology and rheological behavior of ultrahigh molecular weight polyethylene (UHMWPE). As is shown by scanning electron microscope observations, theological measurements, and dissipative particle dynamics simulations, formation of a lubricating phase between the UHMWPE particles is responsible for the viscosity reduction of the UHMWPE. Besides, phase diagram studies on the UHMWPE/NMWP blend suggest that the optimum composition ratio of the blends lies in their composition-sensitive region when the parameter chi and molecular weight of each component are fixed at low shear rates. Meanwhile, the optimum range of parameter chi is above but close to the corresponding binodal curve at high shear rates.