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

• Published in: Polymer (Guilford) 2015-08, Vol.72, p.52-58
• Main Authors: Brüning, Karsten, Schneider, Konrad, Roth, Stephan V., Heinrich, Gert
• Format: Article
• Language: English
• Subjects: Crystallites; Crystallization; Crystallization kinetics; Diffusion; Diffusion rate; Diffusion-controlled rate law; Natural rubber; Networks; Strain; Strain-induced crystallization; Synchrotron wide-angle X-ray diffraction; Temperature dependence
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2015.07.011

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. [Display omitted] •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.