Integrated signals calculated from 1H NMR quantitative analysis. 1H NMR spectra of PHB and PHBV copolymers carried out on a Bruker spectrometer Ascend III HD operating at 400 MHz. The 1H NMR spectra were recorded at 25°C, 3 kHz for spectral width, 1600 Hz for transmitter frequency offset, 3 s for acquisition time and 4 scans. Quantitative conditions were obtained with a 30° pulse (3 µs) and a relaxation delay at 1 s (D1). 1H decoupling applied during acquisition (waltz16 with a pulse of 90µs).