MEASUREMENT OF FOAM MODULUS VIA A VANE RHEOMETER

A vane rheometer was used to measure the modulus of foam systems. Modu lus development in a reactive polyurethane foam system was captured us ing a commercial stress-controlled rheometer with a four-blade vane ge ometry test fixture. The results were compared to those from a tempera ture programmed flooded parallel plate method. The vane geometry metho d was shown to be a convenient and accurate way to measure the physica l gelation time of the reactive foaming system, without the complexity of the temperature-program method. Shaving cream was used as a calibr ation material to show the validity of the vane method for foam modulu s measurements. For open cell foams, the error in the vane method incr eases due to the additional compressibility of the foam. The nature an d magnitude of this error was analyzed via numerical simulation. (C) 1 998 The Society of Rheology.