Folding of Semicrystalline Polymer as Functions of Kinetics, Molecular Weight, and Entanglement

Long polymer chains drastically change their structures from random coils to folded chains. Recent studies using Solid-State NMR spectroscopy and ¹³C selective isotope labeling enabled one to investigate chain-folding structure of polymer in both solution- and melt-grown crystals as a function of kinetics. In this study, we synthesize various ¹³C labeled PLLA samples with different molecular weights. In this presentation, it will be for the first time demonstrated that how kinetics, entanglements, and molecular weights affect chain-folding structure of PLLA in bulk and solution-grown crystals. On the basis of chain-level structure, we will discuss about crystallization mechanisms of long polymer chains at the molecular scale.