Soluble copolymers of diethyl 2‐(methacryloyloxy) ethyl phosphate (DMP) with methyl methacrylate (MMA), methyl acrylate (MA), ethyl acrylate (EA) and butyl acrylate (BA) were synthesized by radical copolymerization in benzene solution using azobis(isobutyronitrile) (AIBN) as initiator. The monomer reactivity ratios of these systems at 60°C were determined by the conventional schemes using the methods of Fineman–Ross, Joshi‐Joshi, and Kelen–Tüdos. DMP underwent a completely random and azeotropic copolymerization with MMA whereas in its reaction with the other acrylates DMP entered preferentially into the polymer chain. The reactivities of DMP‐terminated polymer radicals towards the acrylate monomers were found to be in the order: MMA > EA > MA > BA. An increase in solvent polarity decreased the relative reactivity of DMP for the DMP‐MMA pair. An examination of the molecular weights of the copolymers revealed the occurrence of chain transfer caused by DMP. The copolymer glass transition temperatures were determined and the variations of Tg with copolymer compositions were discussed according to the theory of Johnston, taking into account the effect of the sequence distributions of the comonomers on Tg. The Tgs of the alternating copolymers of DMP with the four alkyl acrylates were calculated.
RE SUM^Pour preciser le mecanisme de lithiation des polydiknes, le squalhe (l), qui est considere comme une molCcule-modkle de polyisoprhe, a Ct C mCtalle A temperature ambiante dans I'heptane, par le complexe sec-butyllithium-N,N,N',N'-tCtramethyl Cthyknediamine (sec-BuLi-TMEDA). L'Ctude des produits obtenus apres desactivation des sites carbanioniques par diffkrents agents de terminaison montre que seul le groupement mCthyle est mCtallC et que la microstructure des produits obtenus varie avec le desactivant.
SUMMARY:To specify the mechanism of lithiation of polydienes squalene (l), which can be considered as a model for polyisoprene, was metalated with sec-butyllithium and N,N,N',N'-tetramethylethylenediamine in heptane (sec-BuLi-TMEDA) at room temperature. The study of products obtained by deactivation of the carbanionic sites using various termination agents showed, that only the methyl group is metalated and that the microstructure of the products varies with the nature of the reagent used for termination.
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