Jean-Marc Corpart

Use of Original ω‐Perfluorinated Dithioesters for the Synthesis of Well‐Controlled Polymers by Reversible Addition‐Fragmentation Chain Transfer (RAFT)

A series of five fluorinated dithioesters PhC(S)SRCH 2 C n F 2n+1 (where R represents an activating spacer and n= 6 or 8) was obtained in fair to high yields (57-88%). These transfer agents were successfully used in reversible addition-fragmentation transfer (RAFT) of styrene (S), methyl methacrylate (MMA), ethyl acrylate (EA) and 1,3-butadiene. Well-chosen fluorinated dithioesters were able to lead to a good control of the radical polymerization of these monomers (i.e., molar masses of the produced polymers increased linearly with the monomer conversion and the polydispersity indexes ranging between 1.1 and 1.6 remained low). The relationship between the structures of the dithioesters and the living behavior of the radical polymerization of these above monomers is discussed and it is shown that the nature of the R group influences the living behavior from different contributions to radical stabilization. Furthermoren the RAFT process alos yielded PMMA-b-PS and PEA-b-PS block copolymers bearing a fluorinated moiety.

Radical telomerization of 1,3‐butadiene with perfluoroalkyl iodides

The radical telomerization of 1,3-butadiene in the presence of 1-iodoperfluorohexane and 1-iodo-perfluorooctane (R F I) is presented. Experimental parameters (such as the nature of the radical initiaor, temperature, solvent and initial molar ratios of the reactants) were varied to increase both 1,3-butadiene and R F I conversions. Best conditions are reached at 140-150°C with di-ter-butyl peroxide as initiator and acetonitrile as solvent. According to different conditions, the monoadduct and higher order telomers were synthesized with average number molecular weights ranging from 250 to 4 000 as determined by 1 H NMR spectroscopy and elemental analysis. 80% of the 1,4-adducts were noted to lack a terminal iodine atom. The transfer constant of R F I towards 1,3-butadiene was determined to be C T = 2.59 at 145°C witch induces the formation of nonfunctional oligomers when a high [butadiene] 0 /[R F I] 0 molar ratio was used.