Study on Synthesis and Characterization of Polystyrene-b-poly (Glycidyl Methacrylate) diblock copolymers

Abstract

The living poly(styryl)lithium was synthesized by anionic polymerization with the protection of argon under normal pressure, where styrene, toluene, THF, n-butyllithium and small amount of LiCl were used as monomer, solvent, polar reagent, initiator and additive, respectively. Polystyrene-b-poly(Glycidyl Methacrylate) diblock copolymers (PS-b-PGMA) with well-defined structure and narrow molecular weight distribution (Mw: Mn <1.1)were prepared by the copolymerization reaction of poly(styryl)lithium with glycidyl methacrylate (GMA) at proper temperature. The copolymers were characterized using GPC, 1H-NMR, 13C-NMR, TLC and Hydrochloric acid-Dioxane Argentimetric method. The effects of additives, copolymerization temperature on the content of side epoxy group were also studied. The results showed that 1, 1-Diphenylethylene (DPE) end-capped poly(styryl) carbanion could effectively initiate GMA in toluene in the presence of LiCl and a small amount of THF to prepare PS-b-PGMA with well-controlled molecular weight and narrow molecular weight distribution. No chain transfer reaction was spotted in toluene. It was also found that the optimal reaction temperature was -65°C within the set range of molecular weight in the experiments herein.