✦ LIBER ✦

Sizes of long branches in low density polyethylenes

✍ Scribed by Daniele C. Bugada; Alfred Rudin

Publisher: John Wiley and Sons
Year: 1987
Tongue: English
Weight: 335 KB
Volume: 33
Category: Article
ISSN: 0021-8995
DOI: 10.1002/app.1987.070330108

No coin nor oath required. For personal study only.

✦ Synopsis

13C-NMR spectroscopy and size exclusion chromatography have been used to determine the mean length of long branches in a number of high pressure process low density polyethylenes (LDPEs). 13C-NMR analyses count all branches longer than C5 as "long." The polyethylenes studied all had 2-3 long branches per lo00 carbons. The mean branch length was of the order of 200-300 carbons in length. The size of long branches increases with increasing an of the parent.

polyethylene, but the size of long branches relative to the overall macromolecular size decreases with increasing an. The mean molecular weight of the long branches is some 5-20% of an of the particular polymer and decreases as a,, increases. Both autoclave and tubular reactor products were studied.

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