“…The band at 3437 cm −1 (only present in PHA) is associated with O–H bond stretching [ 27 , 28 ]. Bands between 2994 cm −1 and 2852 cm −1 correspond to symmetric and asymmetric stretching of C–H in CH 3 [ 27 , 28 , 29 , 30 , 31 ]; bands at 1721–1745 cm −1 relate to carbonyl group stretching [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ]; bands between 1454 cm −1 and 1358 cm −1 are characteristic of symmetric and asymmetric deformations of the CH 3 bond [ 27 , 28 , 29 , 30 , 33 ]; bands between 1269 cm −1 and 1079 cm −1 relate to deformations of the ether group, C-O-C [ 27 , 28 , 29 , 31 , 33 ]; bands from 955 cm −1 to 1041 cm −1 correspond to rocking of the C–CH 3 bond [ 27 , 28 , 29 , 33 ]; bands at 895–865 cm −1 refer to stretching of the O-CH-CH 3 group [ 27 , 28 , 29 , 30 , 33 ], and bands at 752–751 cm −1 correspond to wagging of CH 3 (present in PLA and PLA–PHA) [ 27 , 30 ]. A more detailed summary of the band locations for each polymeric filament and its bonding/vibration type can be found in Table S1 of the Supplementary Information .…”