The Effect Of Rheological Property On High-Density Polyethylene (HDPE) By Different Lubricants

By employing the new model constant velocity type capillary rheometer with two bore and constant pressure type capillary rheometer, we systematically researched the mechanism of extrusion aberrance, wall slip, melt fracture occurring of high-density polyethylene(HDPE) melt on the extreme flow conditions(extra high shear stress, extra high shear rate) and the different temperatures. Especially, we discussed the influence of absorption action between polymer melt and different kinds of extrusion dies (interface mechanism) on melt flow instability, and the influence of tangle and disentangle, tropism and disentropism of the different flow layers' polymer molecular chain and molecular structure(molecular mechanism) on melt flow instability. At last, we found the different molecule structures of HDPE embodying at the various experiment results.On the meanwhile, in order to improve the melt instability, we applied the PE wax, fluorocarbon elastomer, and fluorocarbon elastomer with PE wax lubricants in HDPE. During the extrusion process, fluorocarbon elastomer with PE wax lubricants had improved the melt flow instability of HDPE. Results indicated the surface gloss during extrusion was improved. But at the higher shear rate, they could not eliminate the extrusion instability.