Figure 7.

(a) IR spectra of PHB composites in the 500 to 4000 cm⁻¹ frequency range. Absorption bands at 1280 and 1720 cm⁻¹ are representative of the PHB content. (b) IR spectra in the 2750 to 3100 cm⁻¹ range, for emphasizing on the effects of the PEG content at the 2930 cm⁻¹ peak.