SYNTHESIS AND PROPERTIES OF 2,2,6,6-TETRAMETHYL-1(1-PHENETHYLOXY)PIPERIDINE, AN INITIATOR FOR LIVING FREE-RADICAL STYRENE POLYMERIZATION

An initiator for living free radical polymerization may be prepared by trapping the benzylic ethylbenzene radical with the stable 2,2,6,6-te tramethylpiperidinyl-1-oxy (TEMPO) radical. The adduct, 2,2,6,6-tetram ethyl-1-(1-phenethyloxy)piperidine (TMPEP), smoothly undergoes thermal fragmentation at temperatures approaching 140 degrees C to afford an active carbon radical capable of initiating polymerization and a passi ve mediating nitroxyl radical to reversibly cap and preserve the propa gating polymer chain.