In situ mid-IR and UV-visible spectroscopies applied to the determination of kinetic parameters in the anionic copolymerization of styrene and isoprene

In situ MIR and UV-visible spectroscopies have been combined in a set-up that has been used to monitor anionic (co)polymerizations of styrene and isoprene. This experimental set-up gives access to the simultaneous and real time concentrations of monomers and actives species during the polymerization, through optical fibers probes immersed in the reaction medium. This method allows fast, accurate and reproducible measurements of the rate constants of the (co)polymerizations investigated even if it does not resort to high vacuum. The influence of some experimental factors has been examined using this method. Among the kinetic parameters governing the (co)polymerization of styrene and isoprene initiated by sec-butyllithium, the influence of the nature of solvent was investigated. It appears that the only reaction to depend on the nature of the aromatic solvent (k(ss,toluene) > k(ss,ethylbenzene)) is the propagation step of styrene

N-Acetoxy-phthalimide (NAPI) as a new H-abstracting agent at high temperature: application to the melt functionalization of polyethylene

International audienceA new H-abstracting agent, N-acetoxy-phthalimide (NAPI), was designed that cleaves mainly homolytically into acyloxyl and aminyl radicals at 190 degrees C. Melt PE grafting experiments confirmed the H-abstraction efficiency of NAPI. It was also shown that the grafting of maleic anhydride increased and at the same time undesired crosslinking lowered compared to peroxides