Study of the microstructure and thermal properties of tetrafluoroethylene-propylene elastomers

Tetrafluoroethylene-propylene elastomers containing from II to 53 mol% tetr afluoroethylene were prepared by emulsion copolymerization in batch operati on. initiated by a redox system with tert-butylperoxybenzoate. Alternating copolymers in a wide range of monomer compositions were obtained. The compo sition curve has one azeotropic point at 46.7 mol% tetrafluoroethylene. The reactivity ratio calculated from NMR and elemental analysis was found to b e r(TFE) = 0.014 and r(P) = 0.18. Highly alternating structures of the copo lymers synthesized were proved. Copolymer compositions calculated from NMR spectra correspond to those obtained by elemental analysis. The thermal pro perties were measured by DSC and TGA and discussed in connection with the c opolymer structure. (C) 1999 Elsevier Science Ltd. All rights reserved.