ISSN:
0449-2978
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The time-dependent birefringence has been measured simultaneously with the stress relaxation on quenched and annealed low-density polyethylene at various temperatures from 10 to 70°C. The strain-optical coefficient increases generally with increasing time, and approaches the equilibrium value, which depends upon the temperature. When the strain-optical coefficient at a fixed time is plotted against temperature, it first increases and then decreases after passing through a maximum at Tmax with increasing temperature. The higher the degree of crystallinity, the higher are the equilibrium values of the strain-optical coefficient and Tmax. The curves for strain-optical coefficient versus time and relaxation modulus versus time below Tmax can be superposed well by a horizontal shift along the abscissa. The optical shift factor obeys the original WLF equation, while the mechanical shift factor is much larger than the optical one. The molecular mechanisms corresponding to this dispersion of the strain-optical coefficient and viscoelastic αc absorption peak near Tmax are discussed.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1967.160050607
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