Influence of mechanical and fatigue loading on crystallization of carbon black-filled natural rubber

Crystallization occurs when rubber is loaded in tension. It is caused by an alignment of macromolecular chains. Crystallization is characterized using sequential X-rays diffraction analysis. The objective of this work is to highlight the link between loading conditions and crystallization. Investigated conditions consist in: (i) monotonic tensile loading, (ii) stress relaxation and (iii) fatigue. Results show that crystallization increases when the maximum stretch is increased and that a minimum stretch level, lambda(c), is required to start crystallization. Relaxation also increases crystallization. Increasing temperature decreases the crystallization level. Fatigue loadings also tend to decrease crystallization in particular when the minimum stretch is close to the critical stretch lambda(c).