Application of nuclear magnetic resonance to the investigation of structural changes in fluorine-containing copolymers on vulcanization

The NMR of Polymers

“…When J « {j , the spectrum of this molecule consists of two pairs of lines of the same intensity and in each pair the lines are at a distance J (page 81). This spectrum may be obtained if resonance is excited with an alternating field at constant frequency W and the polarizing field is changed so that it gradually approaches the resonance region.…”

“…133. Lines of l~ (a) and lH (b) nuclei in the NMR spectrum of the fluoro copolymer Viton, vulcanized with hexamethylenediamine (the spectrum was determined at 30·C) [81]. 1) Starting polymer; 2) mixture of polymer with 10 parts by weight of hexamethylenediamine; 3) the same mixture after wlcanization at 120·C for 10 min.…”

“…134. Line of l~ nuclei in the NMR spectrum of the fluoro copolymer Viton, vulcanized with hexamethylenediamine (10 parts by weight) with the addition of 10 parts by weight of magnesium oxide [81]. 1) Starting polymer; 2) after wlcanization at 120·C for 10 min.…”

“…The NMR method has been used [81] to study the vulcanization of rubbery fluoro copolymers such as Viton and Kel F-3700. It was observed that the vulcanization of fluoro rubbers by hexamethylenediamine produces a substantial change in the form of the resonance line of fluorine and hydrogen (Fig.…”