✦ LIBER ✦

New evidence of the presence of internal electron donors in active sites of heterogeneous Ziegler-Natta catalysts

✍ Scribed by Junting Xu; Linxian Feng; Shilin Yang; Yinan Wu; Yiqing Yang; Xiangming Kong

Publisher: John Wiley and Sons
Year: 1996
Tongue: English
Weight: 310 KB
Volume: 17
Category: Article
ISSN: 1022-1336
DOI: 10.1002/marc.1996.030170906

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✦ Synopsis

Abstract

Poly(propylene) samples produced by heterogeneous Ziegler‐Natta catalysts containing different internal electron donors were fractionated by using temperature rising elution fractionation; some key fractions were analyzed with ^13^C NMR. It was found that internal electron donors with different structures can convert aspecific active sites into different isospectrific ones. The employment of bis(2‐ethylhexyl) phthalate as internal electron donor leads to chemically inverted structures in the atactic fraction. This suggests that an internal electron donor may also exist in the environment of aspecific active sites.

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