Encyclopedic Dictionary of Polymers

2011 Edition
| Editors: Jan W. Gooch

Rheometer, Foam

  • Jan W. Gooch
Reference work entry
DOI: https://doi.org/10.1007/978-1-4419-6247-8_10028

n A special type of capillary rheometer developed by W. Kostyrzewski to measure the density and viscosity of foaming polyurethane immediately after mixing. Creaming time is also measured. It consists of a three-section, vertical acrylic tube, adapted at the bottom to a reaction–injection–molding mixer (RIM machine). The bottom chamber is large enough to contain the mix charge delivered by the RIM machine, and the mixture rises through an instrumented and temperature-controlled “capillary” as the foam forms and expands. The instruments are connected to an analog-to-digital converter and computer. The foam passes up through the capillary into a larger-diameter collection chamber and raises a floating disk that can be weighted to adjust the pressure on the foam as it rises. Flow rate is inferred from foam density; rate of change of density, and shear rate at the capillary wall are computed from flow rate. Shear stress is inferred from the pressure–transducer readings.

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Jan W. Gooch
    • 1
  1. 1.AtlantaUSA