NMR studies on semicrystalline polymer dynamics and morphology

Abstract

This cumulative thesis investigates how molecular structure controls intracrystalline chain dynamics (ICD), morphology, and macroscopic properties in semicrystalline polymers. Solid-state NMR, supported by SAXS/WAXS, DSC, and mechanical analysis, is used to study three model systems: poly(3-hydroxybutyrate) (P3HB), precision brominated polyethylene (PE21Br), and keto-functionalized polyethylene (KetoPE). The results show that ICD can influence lamellar evolution, crystallization behavior, and mechanical response. P3HB demonstrates time-dependent chain mobility associated with structural and property changes, whereas PE21Br and KetoPE reveal how functional-group placement, crystal packing, and chemical modification can suppress or preserve intracrystalline mobility. Overall, the thesis connects polymer architecture, crystal dynamics, and material performance, providing guidance for the design of functional semicrystalline polymers.