Rheological properties of LDPE processed by conventional processing machines

Document Type

Article

Publication Date

9-1-2003

Abstract

The impact of applied processing history and the postprocessing annealing on the Theological properties of low-density polyethylene (LDPE) have been studied employing various kinds of conventional processing machines. Processing by a corotating twin-screw extruder (Co-TSE) and an internal batch mixer depressed the drawdown force, one of the elastic properties of a melt, to a great extent, even though molecular weight and the polydispersity did not change. On the other hand, the sample processed by a two-roll mill exhibited the drawdown force as high as the original pellets, which is owing to the intermittent stress history instead of the relentless one in the Co-TSE and the internal batch mixer. Furthermore, the effect of screw configuration in the Co-TSE has also been investigated. It was found that the processing by conveying screws depressed the drawdown force and melt fracture more than that by kneading blocks as long as the torque and the residence time are the same. The large, abrupt, and frequent change in flow direction in the Co-TSE with kneading blocks prohibits the molecular orientation, which leads to disentanglement associated with long-chain branches. © 2003 Wiley Periodicals, Inc.

Identifier

0041340608 (Scopus)

Publication Title

Advances in Polymer Technology

External Full Text Location

https://doi.org/10.1002/adv.10047

ISSN

07306679

First Page

179

Last Page

187

Issue

3

Volume

22

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