“…Twenty per cent solutions were needed for HTPB-A and C prepolymers because their initial hydroxyl concentrations were only 0.5 to 0.7%. The hydroxyl content was determined using the 3615 cm-1 band by the peak height method with the base line drawn from 3700 to 3200 cm-1, and by graphical integration (8,9) of the area delimited by the absorption bands between 3700 to 3200 cm-1. The hydroxyl absorbance must be corrected for the interference of the antioxidant.…”