4M Knowledge base - papers

T. Hanemann (a), (b) and J. Aroni (a)

(a) Forschungszentrum Karlsruhe, Institut f. Materialforschung III, D-76021 Karlsruhe, Germany
(b) Albert-Ludwigs-Universität Freiburg, Institut f. Mikrosystemtechnik (IMTEK), D-79110 Freiburg, Germany

Abstract

With respect to feedstock development for different ceramic injection molding techniques the influence of various process parameters during feedstock development was investigated systematically. First the dispersant concentration at the fillers surface was changed in a wide range. The impact on the particle size distribution was measured. Second the size and the geometry of the used stirrers for compounding in an unsaturated polyester resin as polymer matrix were varied. The resulting composite flow properties at a fixed solid load and different temperatures were determined experimentally using a cone and plate rheometer. Increasing dispersant amounts at the alumina surface lead to a change of the particle size distribution and to a significant composite viscosity drop. The use of different stirrers affects directly the composite viscosity as well as the flow behaviour to a certain extent.

M. Sahli (a,c), C. Roques-Carmes (a), R. Duffait (b) and C. Khan Malek (c)
a Laboratoire de Microanalyse des Surfaces (LMS), ENSMM, 26 Rue de l’Epitaphe,
b Centre de Transfert des Micro et Nanotechnologies (CTMN), 39 Avenue de l’Observatoire,
c Laboratoire FEMTO-ST, CNRS UMR 6174, Département LPMO, 32 Avenue de l’Observatoire, 25000 Besançon, France.

Abstract

A study of the rheological properties of two types of amorphous polymeric materials (PMMA and COC) was conducted in order to optimize the operating conditions for the hot embossing of the polymers. The glass transition temperature (Tg), the melt flow index (IF), and the viscosity as a function of shear stress were determined. These intrinsic properties were related to the aptitude of the polymers to reproduce the geometrical shape and surface states of a microstructured mould. The flow imposed to the polymeric material in shear or elongational mode was correlated to this rheological approach.