Effect of nanoparticles on the deformation-induced crystallization of polymers

In contrast to the extensive research on the mechanisms of deformation-induced crystallization (DIC) in pristine polymers, the influence of nanoparticles on these processes has received comparatively less attention. In this study, we investigate the role of nanoparticles in the crystallization behavior of semicrystalline polymers using a combination of small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC). Following cold pre-deformation and subsequent thermal annealing, DSC measurements reveal comparable crystallinity and melting temperatures between the semicrystalline nanocomposites with dilute nanoparticle loadings and their pristine counterparts. Consistently, SAXS and WAXD analyses show similar long periods and lamellar thicknesses, indicating that the nanoparticles exert negligible influence on the overall crystallization kinetics and the stability of the crystal phase. Interestingly, pronounced scattering anisotropy is observed in the semicrystalline polymer nanocomposites both along and perpendicular to the deformation direction, whereas crystalline orientation in pristine polymers appears only along the stretching direction. This observation suggests that nanoparticles strongly affect the deformation-induced polymer morphology, likely through hydrodynamic interactions. These findings highlight a non-trivial role of nanoparticle in modulating the crystallization and morphological evolution of deformation-induced semicrystalline polymers, providing new insights for the rational design of advanced polymer nanocomposites.