Journal article
Planar elongation of soft polymeric networks
The Danish Polymer Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark1
Department of Chemical and Biochemical Engineering, Technical University of Denmark2
Manufacturing Engineering, Department of Mechanical Engineering, Technical University of Denmark3
Department of Mechanical Engineering, Technical University of Denmark4
Coloplast Danmark AS5
Administration, Department of Chemical and Biochemical Engineering, Technical University of Denmark6
A new test fixture for the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks with application towards pressure-sensitive adhesives (PSAs). The concept of this new geometry is to elongate a tube-like sample by keeping the perimeter constant. To validate this new technique, soft polymeric networks of poly(propylene oxide) (PPO) were investigated during deformation.
Particle tracking and video recording were used to detect to what extent the imposed strain rate and the sample perimeter remained constant. It was observed that, by using an appropriate choice of initial sample height, perimeter, and thickness, the planar stretch ratio will follow lambda(t) = h(t)/h(0) = exp((epsilon)overdot t), with h(t) being the height at time t and (epsilon)overdot the imposed constant strain rate.
The perimeter would decrease by a few percent only, which is found to be negligible. The ideal planar extension in this new fixture was confirmed by finite element simulations. Analysis of the stress difference, sigma(zz) - sigma(xx), showed a network response similar to that of the classical neo-Hookean model.
As the Deborah number was increased, the stress difference deviated more from the classical prediction due to the dynamic structures in the material. A modified Lodge model using characteristic parameters from linear viscoelastic measurements gave very good stress predictions at all Deborah numbers used in the quasi-linear regime.
Language: | English |
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Publisher: | Springer-Verlag |
Year: | 2010 |
Pages: | 1-13 |
ISSN: | 14351528 and 00354511 |
Types: | Journal article |
DOI: | 10.1007/s00397-009-0383-7 |
ORCIDs: | Hassager, Ole , Rasmussen, Henrik K. and Skov, Anne Ladegaard |