Atom transfer radical copolymerization of 2,2,3,3-tetrafluoropropyl acrylate (TFPA) and styrene (St) was successfully conducted in the water dispersion system with ethyl 2-bromoisobutyrate as initiator and CuBr/CuB_2/ phenanthroline as catalyst, respectively. The increase of molar masses with the increase of the total monomer conversion and relatively narrow molar mass distributions of the copolymers exhibited that the good control over the copolymerization was achieved. The apparent monomer reactivity ratios were estimated with extended Kelen- TtidSs method (γ_(st) = 0.48, γ_( TFPA)=0.08) and Fineman-Ross method (γ_(st) = 0.50, γ_(TFPA) = 0.11). It was found that the spontaneous fluorinated "gradient copolymer" was produced in this water dispersion copolymerization system due to the difference of relative reactivity between St and TFPA. Three kinds of emulsifier systems, i.e., sodium laurylsulfonate (SLS), sodium perfluorononenyloxyl benzene sulfonate (OBS)/SLS and sodium perfluoronocaprylate (SPFS)/SLS, were used and examined in this work. The results showed that both good controllability and stable copolymer latex were achieved during the course of the copolymerization by using these emulsifier systems, of which the copolymer latex prepared with OBS/SLS as emulsifier was most stable.

Key words: FREE REDICAL POLYMERIZATION, PROPENOIC ACID ESTER, STYRENE, DISPERSION POLYMERIZATION, PHENANTHROLINE, EBiB