ON ANNEALING OF POLYETHYLENE CRYSTALS FORMED FROM DILUTE SOLUTION

The critical annealing temperature, defined as the temperature at which crystals formed in dilute solution and then dried undergo major alteiations in thermodynamic and morphological properties, has been accurately determined as a function of the initial crystallite thickness. This temperature is shown to obey the theory for the melting of crystals of small size and thus can be identified with the melting temperature. It is, therefore, not necessary, as has been proposed, to endow the chain units within the interior of the crystals with any extraordinary mobility. The well-known changes in properties that are observed upon annealing are merely consequences of the fusion process and recrystallization. © 1969, American Chemical Society. All rights reserved.