Mr Nicolas Clemeur

PhD Student

Academic Background

• Mechanical Engineer - Université Catholique de Louvain (Belgium) June 1997

• Secondary School – Athénée Royal Paul Delvaux, Ottignies (Belgium) June 1992

Research Interests

Simulation, validation and application of a novel melt flow model for highly entangled linear and long chain branched polymers

Supervisors:

• Dr Rulande Rutgers

In the last decade, much progress has been made in the prediction of the flow behaviour of conventional polymers such as linear low density polyethylene and high density polyethylene. However, new developments in polymer synthesis and in the plastics market invite a renewed effort in the development of widely applicable constitutive equations for flow simulations. Drivers are in particular: 
Increased level of control of chain structure, allowing better verification of theoretical correlations with flow behaviour.

The development of novel materials such as polylactic acids and biodegradable polyesters to serve the environmentally sensitive segments of the market.
The unresolved difficulty in predicting simultaneous shear softening and strain hardening behaviour as observed in branched polymer melts such as low density polyethylene (LDPE).

Recently it has become clear how hard it is to model LDPE rheology with existing constitutive equations. The aim is to investigate the predictive power of a number of modifications to existing constitutive models as well as a newly developed molecular model by building the models into existing simulation software. The objective is to develop a model applicable to a wide range of molecular structures. The parameters for the model will be determined through (modified) rheometric devices available in this laboratory and in those of collaborating researchers. In particular stress-strain relationships will be determined in simple shear, uniaxial extension and planar extension flow. The prediction will be validated through comparison with existing and new experimental data. Specifically stress and velocity fields for flow into and out of a slit die, where both shear and extension occur, will be compared to numerical predictions.

Selected Publications

Nicolas Clemeur, Rulande P. G. Rutgers, Benoît Debbaut:
On the evaluation of some differential formulations for the pom-pom constitutive model Rheologica Acta, Accepted

R.P.G. Rutgers, N. Clemeur and J. Husny
The prediction of sharkskin instability observed during film blowing International Polymer Processing, Vol XVII, No.3 2002 214-222.

R.P.G. Rutgers*, N. Clemeur, S. Muke1 and B. Debbaut2 Polyethylene flow prediction with a differential multi-mode Pom-Pom model Korea-Australia Rheology Journal, Vol. 14, No. 1, March 2002 pp. 25-32

Y. Rubin, N. Clemeur and T. Marchal, Numerical simulation of extrusion and coextrusion: shape and interface prediction and die design, Proc. Of the PPS-15 conference, ‘s-Hertogenbosch, The Netherlands, 1999.

T. M. Marchal, N. Clemeur and A. K. Agarwal, Optimisation of the thermoforming process: a few industrial examples, Proc. of the ANTEC ’98 conference, Brookfield CT, Vol. 1, p. 696-670, Ed. Society of Plastic Engineers, Atlanta, USA, 1998.