Table 2. Characteristic FT-IR Peaks for Un-oxidized and Oxidized Natural Rubber

Sample I. D.	Absorption peak, cm−1	Chemical structure
Un-oxidized form	3036	=C-H Stretching
	2924, 2854	-CH3 Stretching, -CH2- Stretching
	1447	-CH2- Bending
	1377	-CH3 Bending
	833	cis-Methine (-CCH3=CH Wagging)
Oxidized form	3449 (Broad)	-O-H (Alcohol)
	1736 (Broad)	-C=O (Aldehyde and Ketone)
	1242	-C-O (Epoxide)
	1072	-C-O (Ether, Alcohol, Peroxide, and Cyclic peroxide)