Accuracy Measurements of an Apparatus for Evaluating Dynamic Viscoelasticity of Irregularly Shaped Small Samples by Applying Grains of Steamed Waxy Rice

Abstract

Comparative measurements of a newly developed microrheometer with a standard dynamic rheometer for concentrated liquid confirmed that the complex modulus was accurately measured with the present instrument by inputting an exact thickness value with a precision in 0.01mm for a pasty sample. To detect the sample temperature indirectly, a foil sensor was attached behind the black metal plate touching the sample. In addition, for the double-side shear mode, it was possible to determine the contact area of two grains using a camera from only one side, by putting a transparent plate over another one. Statistical investigations of the data of steamed waxy rice grains indicated that G^* values were independent of the time elapsed after steaming. Highly reliable G' values were obtained in the range of 15% of the coefficient of variance, when the grains were sandwiched between the plates to the extent of 30% of the initial thickness.