Azoalkanes: A Novel Class of Additives for Cross‐Linking and Controlled Degradation of Polyolefins

Abstract

Abstract 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. magnified image