Crystallization of Precision Polyethylenes

The self-assembly, melting behavior and crystallization kinetics of polyethylenes with moieties placed at an exact equal distance along the backbone will be presented with especial focus on recent studies of the crystalline properties of precision polyethylenes with halogens (as pendant), and acetals (in-chain) groups under rapid and isothermal crystallization from the melt.^1-5 The observed discrete minima in the temperature coefficient of the crystallization kinetics correlates with transitions between polymorphic structures that differ in packing symmetry. The minima or retardation of crystallization kinetics may be due to self-poisoning at the growth front or to differences in nucleation and growth between two polymorphs at the transition temperature. Control over different layered crystalline structures, demonstrate the ability of these novel systems to generate new polyethylene-based materials based on nanostructures at the lamellar and sub-lamellar level not feasible in classical branched polyethylenes.

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