Dynamics and yields of AOTEMPO-mediated polyolefin cross-linking

Strategies employing 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl (AOTEMPO) to control the onset, rate and yield of polyolefin cross-linking are demonstrated and discussed in terms of underlying reaction mechanisms. Rheological studies of a wide range of dicumyl peroxide (DCP) + AOTEMPO formulations confirm that linear low density polyethylene (LLDPE) cross-linking can be delayed precisely and consistently without adversely affecting cure yields. The importance of peroxide thermolysis rates and alkoxy radical fragmentation to reaction outcomes is established by comparison of DCP with alternate initiators, and the compatibility of AOTEMPO cure chemistry with diacrylate coagents is investigated.