Melt free‐radical grafting of maleimides with hindered phenol groups onto polyethylene

Abstract

AbstractA monomeric antioxidant, bearing carbamate groups, was synthesized from the reaction of 3,5‐di‐tert‐butyl‐4‐hydroxybenzyl alcohol and azidomaleimide. Another antioxidant was prepared from the reaction of N‐(4‐hydroxyphenyl)maleimide and 3‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl) propionic chloride in the presence of triethylamine. These fictional antioxidants were grafted onto polyethylene (PE) via melt processing with free‐radical initiators in a minimax molder. The IR spectra of the grafted PE showed that the monomeric antioxidants were added to PE. IR spectroscopy methods were used for the quantitative determination of the extent of grafting of the monomeric antioxidants. Also, the extent of crosslinking was determined from the gel content. To optimize the reaction conditions, we investigated the effects of the initiator concentration, monomeric antioxidant, reaction time, and temperature on the extent of grafting. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2117–2122, 2004