Kinetics of strain-induced crystallization in natural rubber: A diffusion-controlled rate law

•The crystallization rate in NR after a strain jump was studied at various temperatures by synchrotron WAXD.•A diffusion-limited rate law is suggested, in contrast to nucleation and growth models for quiescent crystallization.•Based on chain dynamics, the model predicts crystallization rates as function of temperature and equilibrium crystallinity.

The kinetics of strain-induced crystallization in natural rubber were studied by synchrotron wide-angle X-ray diffraction (WAXD) in a strain jump setup over a broad temperature range. The increase of crystallinity after a strain jump was observed on a millisecond time scale, until a steady state plateau was approached. A novel model, based on chain dynamics scaling laws for diffusion in polymer networks was developed to interpret the time and temperature dependence of the strain-induced crystallization. In contrast to established thermal crystallization models, this model for the strain-induced crystallization proposes that the formation of stretched crystallizable chain segments takes place before the attachment to a growing crystallite.

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