ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Changes occur in the structure of drawn polyethylene when it is annealed at temperatures close to that of the drawing process. Measurements have been made of the oxygen barrier properties and of the thermal expansion coefficient in the draw direction on samples over a wide draw ratio range both before and after annealing at various temperatures. The results are augmented by density, creep modulus, and shrinkage observations. All samples show a drop in the barrier properties and an increase in the thermal expansion after annealing. However, whereas high-draw-ratio samples show relatively small effects, the changes observed at low draw ratios are very large, with some barrier properties even lower than those of the isotropic feedstock. The effects are larger at the higher annealing temperatures. The diffusion and expansion measurements are greatly influenced by the amorphous regions in the polymer; these results are interpreted as a relaxation of internal stresses giving rise to greater accessibility of the intercrystalline regions. Further experimental work is required to exploit these techniques.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1985.180231104
