STUDY ON RADICAL CHEMISTRY OF MONOPEROXYCARBONATES BY ALPHA-METHYLSTYRENE DIMER TRAPPING TECHNIQUE

The initiation mechanisms of OO-t-butyl O-isopropyl peroxycarbonate (B uI) and OO-t-hexyl O-isopropyl peroxycarbonate (HexI) were studied at 140 degrees C by alpha-methylstyrene dimer (MSD) trapping. Alkoxycarbo nyloxy radicals (carbonate radicals) produced from the peroxides were trapped by MSD almost quantitatively, indicating that decarboxylation of carbonate radicals was too slow to compete with addition to the sty reneic double bond even at high temperature. The hydrogen abstraction ability of these peroxides was evaluated in a mixture of MSD and cyclo hexane. Hydrogen abstraction ability of HexI was much lower than that of BuI. In bulk styrene polymerization, BuI acted as a more efficient initiator than the perester type initiator of t-butyl peroxylaurate, k eeping high initiator efficiency up to high monomer conversions.