Controlled radical polymerization has aroused considerable attentions during the past decades due to its ability to adjust the polymer chain structure such as molecular weight

molecular weight distribution

composition

and topology. Transition metals compounds such as copper

iron

ruthenium

nickel

etc have been extensively explored. While the effect of the auxiliary ligands on the polymerization behaviour was rarely investigated. Especially for titanium complexes

only metallocene titanium chloride Cp2TiCl2 was examined under the reduction by Zinc. Herein

the binary systems composed by constrain geometry construction trivalent titanium complex (1) and 1-bromo-1-phenylethane (I1)

(2-bromo-2-propanyl)benzene (I2) and 1-iodo-1-phenylethane (I3)

respectively

were employed to catalyzed radical polymerization of methyl methacrylate (MMA). The influence of initiators on the molecular weight and molecular weight distribution was assayed. The kinetic study of MMA polymerization initiated by 1/I1 indicated linear relationship between MMA conversion and polymerization time

suggesting zero order dependent on MMA concentration. While with the increase of monomer conversion

the molecular weights of the afforded polymers have no obvious change. In addition

with the increase of the ratio of MMA to I1 while keeping the MMA concentration as constant

the molecular weight of the corresponding polymer increased despite the MMA conversion decreased. Meanwhile

with the decrease of the polymerization temperature

the molecular weight of the afforded polymer increased. These results suggested that the polymerization performed in slow initiation

fast propagation. This is consistent with the typical radical polymerization mechanism

but different from those of atom transfer radical polymerization (ATRP) and organometallic mediated radical polymerization (OMRP) which are mediated by organometallic complexes. The above results indicated that the auxiliary ligand has a significantly effect on a radical polymerization process.