Spatial Distribution of the Amorphous Region Constrained by Polymer Crystallites

Many studies have supported the existence of the amorphous region with reduced mobility induced by crystallization in semicrystalline polymers. However, the spatial distribution of the amorphous region with reduced mobility (rigid amorphous region) has not been fully clarified. Therefore, we applied contrast variation small-angle X-ray scattering (CV-SAXS) to the swollen ethyleneoctene copolymer with granular crystallites to clarify the spatial distribution of the rigid amorphous region. The analysis with CVSAXS revealed that the rigid amorphous region existed around the crystallites and bridged among the crystallites. Furthermore, the weight fraction of the rigid amorphous region estimated by CV-SAXS was in good agreement with that obtained by pulsed proton nuclear magnetic resonance measurements.

Automated summary

Many studies have shown that crystallization in semicrystalline polymers leads to the existence of an amorphous region with reduced mobility. However, the spatial distribution of this rigid amorphous region has not been fully understood. In this study, contrast variation small-angle X-ray scattering (CV-SAXS) was used to investigate the swollen ethyleneoctene copolymer with granular crystallites, revealing that the rigid amorphous region exists around and between the crystallites. The weight fraction of the rigid amorphous region estimated by CV-SAXS was consistent with measurements obtained by pulsed proton nuclear magnetic resonance.