Orientation of crystallites in natural rubber under different modes of load

Abstract

: Strain induced crystallization (SIC) is one of the .most influencing factors for the outstanding mechanical properties of natural rubber. It was extensively investigated within the last decades (e.g. Zhang et al. 2013, Brüning 2014). In practical use, and mainly in the case of pre-cracked respectively damaged samples, the strain field around the crack tip is highly inhomogeneous. This will influence the strain induced crystallization. Therefore, the effective crystallite distribution and orientation around the crack tip will be as well inhomogeneous. In contrast to the uniaxial tensile load of rubber with fibre symmetrical distribution of crystallites, in pure shear samples no fibre symmetry is found. The crystallite orientation with respect to the sample geometry will be investigated via x-ray scattering. and the results are used to describe the crystallization under inhomogeneous stretching conditions.