Evaluation of the Physical Properties of Rubbers by Large Amplitude Oscillatory Shear Measurement

• Published in: KOBUNSHI RONBUNSHU 2015/03/25, Vol.72(3), pp.130-140
• Main Authors: TSURUSAKI, Kyoichi, TAKEDA, Rika
• Format: Article
• Language: eng ; jpn
• Subjects: Amplitudes; LAOS; Non-Linear Viscoelasticity; Nonlinearity; Physical properties; Projection; Rubber; Rubber Material; Viscoelasticity; Weathering; Weathering Resistance Index; Weathering Test
• ISSN: 0386-2186; 1881-5685
• DOI: 10.1295/koron.2014-0070

We demonstrate that 3-dimensional plots of non-linear viscoelastic parameters (G’L, G’M and S) proposed by Ewoldt et al. and the 2-dimensional projection maps of two viscoelastic parameters, i.e. the maximum strain γ0 and the frequency f0, are very useful to characterize the physical properties of rubbers. Here, it is crucial that the amplitude oscillatory shear (AOS) (γ0-sweep) should be performed from small (SAOS), in where the viscoelasticity is almost linear (LVE), to large (LAOS) in where the viscoelasticity is nonlinear (NLVE). By 3D plots and their 2D projection maps of the NLVE parameters for the NBR rubber sheet, we found that the boundary between SAOS and LAOS is given by γ0~10% independently of f0, and the rubber material has various NLVE structures in the LAOS region. We apply this method to the evaluation of rubber materials in weathering test and suggest that the decrease of S in the region of large γ0 and large f0 will give an appropriate index to evaluate practical weathering resistance of rubber materials.