A Novel Efficient Ligand in Anionic Polymerization at Elevated Temperature

This work confirmed a novel ligand in the anionic polymerization, lithium phenoxide, which helped to improve the controllability of the polymerization. The stability of n-BuLi against THF at 0 degrees C was effectively improved by adding lithium phenoxide. More than 60% n-BuLi in THF was alive with the presence of lithium phenoxide after stirring at 0 degrees C for 20 min, compared to 2% under same conditions but without lithium phenoxide. The propagation of polymerization of styrene (St) and methyl methacrylate (MMA) were retarded after adding lithium phenoxide. And by adding more than 10 fold lithium phenoxide, completed conversion was achieved in the polymerization of MMA in THF at 0 degrees C. The lithium phenoxide showed both promoting and inhibiting effects in the polymerization of isoprene (Ip): it promoted the formation of 3,4-structure, while mitigated the formation of 1,2- and 1,4-structures. In general, the polymerization rate of Ip was promoted by lithium phenoxide.