7Li-NMR was used to characterize the mixed system of n-butyl lithium (n-BuLi) and potassium t-butoxide (t-BuOk) with different molar ratios in THF and cyclohexane.The anionic block-copolymerization of butyl methacrylate (BMA) and methyl methacrylate (MMA) was initiated by 1

1-diphenyl hexyl lithium and using phenol lithium

sodium t-butoxide and t-BuOk as the side reaction inhibitors.GPC and1H-NMR were used to characterize the structure of the block copolymers.It was found that the exchange reaction of Li in n-BuLi and K in t-BuOK could be generated

in which the inactive lithium t-butoxide and active species with K as the counterion formed.The new species had admirable impact on inhibiting the side reaction in the anionic polymerization of the polar monomers

such as MMA.The surplus t-BuOK in the system could further promote the inhibition effect.When the mole ratio of nt-BuOK/nn-BuLi was not lower than 20

the total yield of the block copolymerization of BMA and MMA could reach up to 100% and the molecular weight distribution was only 1.40 with unimodal distribution even when the copolymerization temperature was up to 40 ℃.Mn determined by GPC well coincided with the calculated theoretically data.The value of nMMA/nBMA in copolymer determined by 1H-NMR was also well close to that of raw material.The results could lay an industrial foundation for the block copolymerization of polar monomers

such as MMA.