ABSTRACT
Polychloroprene rubber is well-known for its ability to strain-crystallize but this fundamental property has received much less attention than in the case of natural rubber. We presently relate on investigations combining mechanical and X-ray diffraction measurements. Crystallization kinetics is first investigated based on tensile impact tests. An approximately logarithmic time-dependence is found for the crystalline content and the time-constants are estimated at various temperatures. The impact of strain-induced crystallization on stress-strain curves during mechanical is further assessed. It is demonstrated that one main effect of strain-induced crystallization is a partial relaxation of the strain experienced by the amorphous fraction, although stress-hardening is simultaneously observed. Based on the stress-optical law, the contribution of the amorphous phase to the stress is shown to level off after crystallization onset, and stress-hardening is attributed to crystallite networking.
