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Development of an Advanced Rheological Tool for Polymer Melt Characterisation

Objective



Today, all major chemical companies active in the
commodity plastics markets (such as Polyethylene (PE),
Polypropylene (PP) and Polystyrene (PS)) are developing
technologies to a) improve their manufacturing cost
position, b) differentiate products for higher added
value markets and c) reduce the product development cycle
time. This is achieved by designing and producing
materials with specific molecular structures and
molecular weight distributions, for example with the
relatively new metallocene technology. In the upcoming
decade this development in polymer catalysis and
synthesis will undoubtedly lead to tailormade materials
that, in many cases, require tailor made processing
conditions and even new processing equipment. The
successful and timely (time to market) development of
new, differentiated grades requires detailed knowledge of
the rheological behavior of polymer melts at realistic
processing conditions since mechanical and optical
product properties such as yield strength, elongation at
break, Young's modulus, optical anisotropy and
dimensional stability, largely depend on processing
history. For polymer melts this means that a thorough
understanding of the viscoelastic constitutive behavior
becomes increasingly important. The availability of
reliable constitutive models, associated material
parameters and robust numerical analysis tools would
allow an early investigation of the performance of a new
grade in industrial processes and thereby provide vital
information to the molecular design process. However, no
generally accepted way to extract the relevant
rheological parameters from experiments has been worked
out ,
nor is there a consensus on the most appropriate
constitutive equations. A third reason that impedes a
wider use of viscoelastic flow simulations today is the
lack of a critical assessment of the reliability of
available (time consuming) simulation programs in model
flow situations that are simple enough for rigorous
experimental control. The outlined Advanced Rheological
Tool (ART) development project defines a pertinent way to
overcome the said obstacles. In the ART project, via a
close cooperation of experienced Universities and
industrial laboratories, stateof the art experimental
techniques to measure velocities and stresses are
combined with robust numerical algorithms to analyse
viscoelastic flows. The key objectives of this project
are to obtain a detailed evaluation of the performance of
constitutive equations in prototype industrial flows and
to identify material parameters at realistic
circumstances. This not only yields improved,
experimentally validated, constitutive models, but also
has a direct impact on the design of materials with
requested processing properties. In conclusion, the ART
project bridges the gap between material design.
classical rheological characterisation and the
application of advanced, realistic constitutive models to
the analysis of industrial flows. This objective is
materialised in an Advanced Rheological Tool (ART).

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

DOW Benelux NV
Address
5,Herbert Dowweg
4530 AA Terneuzen
Netherlands

Participants (7)

ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS
France
Address
Avenue Claude Daunesse Cnrs Ura 1374
06565 Valbonne
Basf AG
Germany
Address
38,Carl-bosch-straße
67056 Ludwigshafen
DSM Research BV
Netherlands
Address

6160 AP Geleen
Eindhoven University of Technology
Netherlands
Address
2,Den Dolech
5600 MB Eindhoven
Polyflow SA
Belgium
Address
16,Place De L'université 16
1348 Louvain-la-neuve
University of Cambridge
United Kingdom
Address
Pembroke Street
CB2 3RA Cambridge
Universität Stuttgart
Germany
Address
Böblinger Straße 70 A
70199 Stuttgart