ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
In propylene polymerization with MgCl2/TiCl4/phthalate ester catalysts, using 2,2,6,6-tetramethylpiperidine as external donor, it has been found that the fraction of atactic polymer formed increased with decreasing ester content in the catalyst. At the same time, however, the stereoregularity of the isotactic polymer fraction, as measured by 13C NMR, increased. Polymerization in the absence of the external donor led to lower polymer yield and a lower stereoregularity of the isotactic fraction. The results indicate that the external donor is actively involved in the generation of isospecific sites, particularly in catalysts having relatively low ester contents.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1992.021930622
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