Abstract: The anionic block copolymerization of methyl methacrylate(MMA) and 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)cyclotrisiloxane (F₃) was carried out with an acetal-functionalized alkyllithium as the initiator, and poly(methyl methacrylate)-b-poly[methyl(3,3,3-trifluoropropyl)siloxane](PMMA-b-PMTFPS) diblock copolymers with a narrow molecular weight distribution were synthesized. The block copolymers were characterized by gel permeation chromatography(GPC), proton nuclear magnetic resonance spectroscopy (¹H NMR), Fourier transform infrared spectroscopy(FTIR) and differential scanning calorimetry(DSC). The results show that the selection of the concentration of F₃ was very important for obtaining PMMA-b-PMTFPS diblock copolymers with high yield when the terminal lithium alkoxide functional poly(methyl methacrylate)(PMMA-OLi) was served as the macroinitiator of anionic ring-opening polymerization(ROP) of F₃. Additionally, DSC results show that the glass transition behaviors of PMMA-b-PMTFPS diblock copolymers were dependent on the content of PMTFPS blocks. The glass transition temperature of PMTFPS blocks is about -69—-70 ℃, and the glass transition temperature of PMMA blocks is about 128—130 ℃.

Key words: Anionic polymerization, Poly(methyl methacrylate), Poly[methyl(3,3,3-trifluoropropyl) siloxane], Block copolymer