ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Time dependence in the melt indexing of polyolefins stabilized against thermally induced changes is well known, the prevalent effect being an increase in melt index toward a steady-state value. The melt index of polyethylenes compounded with carbon black has been found to decrease, in some cases radically, although oxygen uptake data show no evidence of thermal instability. The melt index-time plot can be restored to its normal shape by adding excess quantities of a standard thioether antioxidant. Data are rationalized by assuming that polyethylene adsorbs on the available pigment surface, forming a crosslink network. The thioether antioxidant, however, may adsorb preferentially, thereby restoring the normal response of the polymer to forces resulting in its capillary extrusion. The results emphasize the contribution of chain orientation effects to the time dependence of melt index.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1967.070110704
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