Crystallization of Polymers with a Reduced Density of Entanglements

Abstract

Since methods for reducing macromolecule entanglements have been developed, it has become possible to better understand the impact of polymer chain entanglement on the crystallization process. The article presents basic information about the disentangling of macromolecules and the characterization of the degree of entanglement. The basic knowledge of polymer crystallization was also presented. Then, it was discussed how polymers crystallize during their disentangling. Non-isothermal and isothermal crystallization experiments using disentangled polymers, and for comparison using entangled polymers, are described in more detail. The influence of disentangling on both nucleation and crystal growth is highlighted. It is also shown how the crystallization of polymers changes when macromolecules re-entangle.

Crystallization of the β-Form of Polypropylene from the Melt with Reduced Entanglement of Macromolecules

“…There are variants of this method, e.g., stabilization of the disentangled state in PP can be achieved by crystallization while cooling the hot solution. In recent years, studies have been carried out on the crystallization of a number of polymers after entanglement reduction, e.g., polylactide, poly(ethylene oxide), polyethylene, and isotactic polystyrene [ 35 ].…”