The Effect Of Lewis Acid On Secondary Chloride-Initiated Atom Transfer Radical Living Polymerizations Of MMA

Butyl chloride (SBC) in the presence of aluminium trichloride (AlCl₃), successfully initiated the atom transfer radical polymerization of methyl methacrylate (MMA) with the iron dichloride tetrahydrate (FeCl₂·4H₂O) / triphenyl phosphine (PPh₃) as catalyst in n-butanol at 80℃. The results showed that MMA can polymerize with controlled characteristic when Fe/Al=l:l. The polymerization is first order reaction with respect to monomer concentration from the kinetics plot. The polymerization displayed living character as evidence by a linear increase of molecular weight with conversion and a relatively narrow molecular weight distribution (MWD). Moreover the polymer was charactered with GPC and ¹H-NMR respectively. Initiator fragment was founded in polymer by 1^H-NMR. The polymerization of styrene initiated by PMMAC1 continued and another polymer with larger molecular weight was got All these above proved that the polymerization had the characteristics of controlled/"living" radical polymerization. The effect of AlCl₃ was discussed and the mechanism of atom transfer radical polymerization of MMA by SBC/AlCl₃ was presumed.When ruthenous chloride triphenyl phosphine (RuCl₂(PPh₃)₃) was replaced for FeCl₂ as catalyst, polymerization of MMA initiated by SBC in toluene at 80 ℃ indicated living characteristic. Not only the plot of ln[M]₀/[M]^t displayed first order kinetics, but also the molecular weight increased linearly with the conversion of monomer, and the polymerization rate increased in the ratio of Ru/Al=10:1. Using Al(i-Bu)₂(OBu) to replace AlCl₃, the polymerization of MMA had living feature and the initiation activity was improved. The conversion of monomer increased to 70%. However there was still an inducing period. While there was no an inducing period in ATRP of MMA catalyzed by SBC/FeCl₂/PPh₃/Al(OBu)₃ with the mole ratio of...