Effect of Combining Boron Nitride With Fluoroelastomer on the Melt Fracture of HDPE in Extrusion Blow Molding

摘要

Boron nitride (BN) is a new polymer processing aid which not only eliminates surface melt fracture in the extrusion of molten polymers,but also postpones the critical shear rate for the onset of gross melt fracture to significantly higher values that depend on resin type and additive concentration.In this work,the influnece of BN as a polymer processing additive is first examined in the extrusion blow molding of high-density polyethylene(HDPE) resins in order to evaluate its usefulness and performance in operations other than continuous extruxion.Th eequipment used includes both a Battenfed/Fisher 50-mm extrusion blow molding machine and a parallel-plate rheometer.Two types of HDPE,which are blended with boron nitride at various concentration levels,are tested accordingly.It is found that the and induction time paly an important role in eliminating melt fracture.Finally,the influnece of combining BN with fluoroelastomer,as an enhanced and potentially that such a combination is a superiro processing aid that allows extrusion blow molding at very hgih shear rates.