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Azoalkanes: A Novel Class of Additives for Cross‐Linking and Controlled Degradation of Polyolefins
Author(s) -
Aubert Mélanie,
Roth Michael,
Pfaendner Rudolf,
Wilén CarlEric
Publication year - 2007
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200600498
Subject(s) - polyethylene , rheology , materials science , melt flow index , degradation (telecommunications) , polymer chemistry , free radical reaction , peroxide , chemical engineering , composite material , polymer , organic chemistry , radical , chemistry , copolymer , telecommunications , computer science , engineering
A series of symmetrical and unsymmetrical azoalkanes were synthesized and their potential as a free‐radical source for rheology modification of polyolefins was investigated. The experimental results show that unsymmetrical azoalkanes, in particular N ‐cyclohexyl‐ N' ‐ tert ‐octyldiazene ( 13 ), can be successfully used for manufacturing controlled‐rheology poly(propylene) and cross‐linked high‐density polyethylene. For example, the melt flow rate of a general‐purpose poly(propylene) (MFR = 14) could be increased to a value of 800 when 0.75 wt.‐% of azoalkane 13 was added during reactive processing. In parallel, it was found that 13 has a remarkable efficiency for free‐radical‐induced cross‐linking of high‐density polyethylene, resulting in similar gel contents to dicumyl peroxide.