New structures from the thermal rearrangement of polybutadiene revealed by 2D HSQC NMR

Studies on thermo-oxidative degradation of synthetic rubbers 1-4 and 1-2 polybutadienes

“…The main compounds were CO 2 , CO, H 2 O, and some hydrocarbons and the same for both 1,4 and 1,2-PB, which is comparable to the former observed in an inert atmosphere [6][7][8][9][10][11][12][13]. At high temperatures, under N 2 , PBs can rapidly decompose [6][7][8][9][10][11][12][13]. In this study, the decomposition of PBs had also occurred, but there was not a participation by oxygen.…”

“…1 H NMR spectra were acquired using 32 K data points, a spectral width of 4,789 Hz, an acquisition time of 3.42 s, a relaxation delay of 2 s, and a pulse width of 90° (10 µs), at 64 scans. 13 C NMR spectra were acquired using 131 K data points, a spectral width of 25, at 126 Hz, an acquisition time of 2.61 s, a relaxation delay of 5 s, and a pulse width 90° (8.5 µs), at 16,384 scans, and the nuclear Overhauser effect (NOE) was suppressed by gating the decoupler sequence [6].…”

“…So, to exclusively observe the oxidation, PBs were isothermally heated at 100°C, in the air. Structural modifications during heating were monitored by FTIR, 1 H, 13 C NMR.…”