Viscoelasticity measuring apparatus

Abstract

Provided is a viscoelasticity measuring apparatus in which an undesirable sample shape change such as a buckle caused as a result of thermal expansion of a sample is eliminated so as to prevent a deformation in a displacement detector direction due to the thermal expansion and a bending of the sample between a sample grasping member and a chuck, to thereby improve accuracy of measurement. In the viscoelasticity measuring apparatus, a thin part is provided in a part of an elastic arm for holding the sample so as to be easily deformed by a thermal expansion force of the sample. Thus, an undesirable shape change such as the buckle generated when the sample is expanded thermally is effectively eliminated, and necessary stiffness is maintained with respect to a load of the sample and hence accuracy of measurement is improved.

Description

technical field [0001] The present invention relates to a dynamic viscoelasticity measurement device, and its purpose is to improve the so-called accuracy of data representing a true value. Background technique [0002] A dynamic viscoelasticity measurement device (hereinafter referred to as DMA) is a device for analyzing the mechanical properties of a sample by applying a strain or stress that changes with time (vibration) to the sample and measuring the resulting strain or stress of the sample. Most of these devices have a problem in that when the sample to be measured is fixed on the holding member and the temperature dependence of the sample is measured, even if there is thermal expansion, the fixing force of the holding member is stronger and the sample itself bends. Wait. Therefore, there is known a viscoelastic device composed of two sample holding members holding both ends of the sample, which do not move in the direction in which stress or strain is applied, and wh...

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Problems solved by technology

Most of these devices have a problem in that when the sample to be measured is fixed on the holding member and the temperature dependence of the sample is measured, even if there is thermal expansion, the fixing force of the holding member is stronger and the sample itself bends. Wait

[0006] However, when the expansion rigidity of a sample such as a polymer material is lower than the rigidity of the elastic arms in the direction connecting the two ends of the sample, the gap between the sample holding members may not expand by an amount corresponding to the expansion amount of the sample, and data accuracy cannot be improved.

In particular, if Image 6 As shown, in the region exceeding the glass transition temperature Tg, the thermal expansion of the sample discontinuously increases and softens, which reduces the rigidity of the sample, so the rigidity of the elastic arm becomes relatively large, and the elastic arm will not expand in the expansion direction of the sample. Absorbs the amount corresponding to the amount of thermal expansion of the sample

As a result, thermal expansion in the direction connecting both ends of the sample cannot be released, whereby the sample no longer maintains a shape such as a cuboid or a cylinder, causing problems such as Figure 5 Buckling of the sample shown in (a), or Figure 5 As shown in (b), there is an unexpected deformation such as sample bending between the sample holding member and the clamp, which makes it difficult to measure the original elastic modulus and deteriorates the accuracy of the data.

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