Study of Viscoelastic behavior and a mosaic block structure in polyethylene single crystals

Viscoelastic measurements and X-ray analyses were made of linear and branched polyethylene (PE) single crystals prepared from dilute solution under isothermal crystallization conditions and on annealed crystals of the same samples. As the long period of the annealed samples increases, the absorption temperature of the crystalline absorption increases, but its intensity decreases. The primary absorption (αa) appears in branched PE single crystal mats following annealing, and its intensity is correlated with the αa absorption. Defect regions are introduced into the crystalline phase of PE single crystals by annealing. These defect regions are interpreted in terms of a mosaic block structure from paracrystalline theory. In the case of annealing at temperatures below 100°C, where thickening of single crystals does not occur, the volume of a mosaic block within single crystals is invariable, while the defect regions surrounding the mosaic block increase with an increase in the annealing temperature. On the other hand, if the annealing is at temperatures above 100°C, where thickening of the single crystals occurs, the volume of a mosaic block increases and merging of the blocks results. Crystalline perfection of a mosaic block is discussed from the relationship between generating a mosaic block structure by annealing and its Viscoelastic behavior.