抄録
In the preceding paper1), a report was made of the study enactted by one of the authors of the stress-strain relation that was obtained from the phenomenological theory of finite deformation. So far as the incompressible materials were concerned, the relation was written as follows:
(1)
where f denoted the tension at extension ratio α, A, B, and C were constants.
In this paper, the applicability of the Eq. (1) to the stress-strain behavior of styrene-butadiene rubber (SBR) and butadiene rubber (BR) was tested, and the temperature dependences of the values of A, B, C were examined. This is, however, only a preliminary examination, because the data discussed in this paper were determined while making the study of fracture phenomena, and little attention was paid to attaining equilibrium state in obtaining the data.
SBR and BR were both cured with tetramethyl thiuram disulfide and contained 5 parts of zinc oxide and 2 parts of stearic acid per 100 parts of rubber. The stress-strain data were determined by means of an Instron type tester at various temperatures between-40 and 120°C at a crosshead speed 50mm/min.
It was found that at temperature over 30°C, fracture occurred at low extensions (α>3) and Mooney-Rivlin equation (Same tipe equation as Eq. (1) where C=0) was in agreement with the data over 30°C, and that at temperatures below 30°C, the experimental stress-strsin relations almost coincided with the relation of Eq. (1) in the extension range α<4.5, while Mooney-Rivlin equation coincided with the data only in the extension range α<3. It was found also that the values of A for SBR and BR showed almost linear increase with temperature above 30°C, the values of B and C decreased with increase of temperature and C were almost 0 for the data above 30°C.
