ISSN:
0449-2978
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
To determine the true reason for the increase in birefringence and the decrease in relaxation modulus for high-density polyethylene with rising temperature, changes in crystalline structure as well as in thermal, viscoelastic, and rheo-optical properties with temperature were measured, by several techniques, including DSC, DLI, infrared dichroism, x-ray diffraction, and NMR. The values for degree of crystallinity obtained from the DSC fusion curve, density, and infrared absorbances coincide very well and show almost no divergence till about 80°C. The optical vertical shift factor pT can be related to the ratio of the orientation function for the crystal c axis at an arbitrary temperature to that at the references temperature, fε/fε0. The mechanical vertical shift factor bT, on the other hand, is associated with the temperature dependence of the mobile fraction, as determined by NMR measurements, but not with variations in degree of crystallinity.
Zusätzliches Material:
17 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1970.160080715
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