PMID- 33918780
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20210502
IS  - 2073-4360 (Electronic)
IS  - 2073-4360 (Linking)
VI  - 13
IP  - 8
DP  - 2021 Apr 9
TI  - Applicability of the Cox-Merz Rule to High-Density Polyethylene Materials with 
      Various Molecular Masses.
LID - 10.3390/polym13081218 [doi]
LID - 1218
AB  - The Cox-Merz rule is an empirical relationship that is commonly used in science 
      and industry to determine shear viscosity on the basis of an oscillatory 
      rheometry test. However, it does not apply to all polymer melts. Rheological data 
      are of major importance in the design and dimensioning of polymer-processing 
      equipment. In this work, we investigated whether the Cox-Merz rule is suitable 
      for determining the shear-rate-dependent viscosity of several commercially 
      available high-density polyethylene (HDPE) pipe grades with various molecular 
      masses. We compared the results of parallel-plate oscillatory shear rheometry 
      using the Cox-Merz empirical relation with those of high-pressure capillary and 
      extrusion rheometry. To assess the validity of these techniques, we used the 
      shear viscosities obtained by these methods to numerically simulate the pressure 
      drop of a pipe head and compared the results to experimental measurements. We 
      found that, for the HDPE grades tested, the viscosity data based on capillary 
      pressure flow of the high molecular weight HDPE describes the pressure drop 
      inside the pipe head significantly better than do data based on parallel-plate 
      rheometry applying the Cox-Merz rule. For the lower molecular weight HDPE, both 
      measurement techniques are in good accordance. Hence, we conclude that, while the 
      Cox-Merz relationship is applicable to lower-molecular HDPE grades, it does not 
      apply to certain HDPE grades with high molecular weight.
FAU - Rathner, Raffael
AU  - Rathner R
AD  - Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, 
      Altenberger Str. 69, 4040 Linz, Austria.
FAU - Roland, Wolfgang
AU  - Roland W
AUID- ORCID: 0000-0002-0213-6118
AD  - Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, 
      Altenberger Str. 69, 4040 Linz, Austria.
FAU - Albrecht, Hanny
AU  - Albrecht H
AD  - Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, 
      Altenberger Str. 69, 4040 Linz, Austria.
FAU - Ruemer, Franz
AU  - Ruemer F
AD  - Borealis Polyolefine GmbH, Sankt-Peter-Strasse 25, 4021 Linz, Austria.
FAU - Miethlinger, Jurgen
AU  - Miethlinger J
AD  - Institute of Polymer Extrusion and Compounding, Johannes Kepler University Linz, 
      Altenberger Str. 69, 4040 Linz, Austria.
LA  - eng
PT  - Journal Article
DEP - 20210409
PL  - Switzerland
TA  - Polymers (Basel)
JT  - Polymers
JID - 101545357
PMC - PMC8069698
OTO - NOTNLM
OT  - Cox-Merz rule
OT  - extrusion
OT  - high-viscosity HDPE materials
OT  - modelling and simulation
OT  - rheology
COIS- There are no conflicts to declare.
EDAT- 2021/05/01 06:00
MHDA- 2021/05/01 06:01
PMCR- 2021/04/09
CRDT- 2021/04/30 01:10
PHST- 2021/03/23 00:00 [received]
PHST- 2021/04/07 00:00 [revised]
PHST- 2021/04/08 00:00 [accepted]
PHST- 2021/04/30 01:10 [entrez]
PHST- 2021/05/01 06:00 [pubmed]
PHST- 2021/05/01 06:01 [medline]
PHST- 2021/04/09 00:00 [pmc-release]
AID - polym13081218 [pii]
AID - polymers-13-01218 [pii]
AID - 10.3390/polym13081218 [doi]
PST - epublish
SO  - Polymers (Basel). 2021 Apr 9;13(8):1218. doi: 10.3390/polym13081218.