SUSPENSION BROMINATION OF HIGH-DENSITY POLYETHYLENE

High‐density polyethylene powder has been brominated in suspension. The product was characterized by various physicochemical methods to determine the nature and effect of the substitution. Analysis of the infrared spectra indicates an initial addition reaction to terminal vinyl double bonds, followed by a substitution reaction on the polymer chain. The kinetic and thermal data show that the pseudo‐first‐order reaction occurs in the amorphous regions only. The brominated sites function as chain defects to decrease the crystallinity of the melt‐recrystallized polymer, prevent annealing, and cause intensity changes in the mechanical α relaxation. Limits are observed in these effects, however, which confirms the expected “blocky” rather than random nature of the substitution. Copyright © 1979 John Wiley & Sons, Inc.