Table 6.

IR band assignment of WPI.

Wavenumber (cm−1)	Peak Assignment
3600–3000	Stretching vibrations of −OH and −NH
3000–2850	Stretching vibrations of C−H
1632	Amide I
1520	Amide II
1400–1200	Amide III
1040	Stretching vibrations of C-O