Role of stress relaxation in polymer crystallization under fast stretching

The industrial processings of commercial polymers like fiber spinning, film stretching and plastic molding commonly hold a fast stretching process for crystallization. How the limited stress relaxation during fast stretching plays its role in polymer crystallization remains as unclear. We performed dynamic Monte Carlo simulations of stress-induced polymer crystallization and found that stress relaxation mainly plays a kinetic role rather than the expected thermodynamic role. In comparison to strain-induced polymer crystallization under parallel conditions, the intermolecular relaxation hinders the intramolecular relaxation, and hence retards crystallization upon fast stretching. Furthermore, stress relaxation is enhanced by crystal reorganization in the post-growth stage of polymer crystallization, which influences crystallinity harvest and crystal morphologies.