Table 4: Characteristic infrared bands of PLA, PEO, and PCL.

PolymerPosition (cm−1)Vibrational modeAbbreviation

2993Asymmetrical stretchingν as(CH2)
2943Symmetrical stretchingν s(CH2)
1755Stretchingν(C=O)
1450Asymmetrical scissoringδ as(CH3)
PLA1360Symmetrical scissoringδ s(CH3)
1182Asymmetrical stretching + twistingν as(C–O) + τ(CH3)
1086Symmetrical stretchingν s(C–O–C)
1045Symmetrical stretchingν s(C–CH3)
868Stretchingν(C–COO)

2946Asymmetrical stretchingν as(CH2)
2886Symmetrical stretchingν s(CH2)
1468Scissoringδ(CH2)
1361Waggingω(CH2)
1343Waggingω(CH2)
PEO1281Twistingτ(CH2)
1242Twistingτ(CH2)
1150Stretchingν(CO)
1110Stretchingν(CO)
1062Stretchingν(CO)
963Rockingρ(CH2)
843Rockingρ(CH2)

2946Asymmetrical stretchingν as(CH2)
2864Symmetryical stretchingν s(CH2)
1726Stretchingν(C=O)
PCL1294Stretchingν crystalline
1243Asymmetryical stretchingν as(C–O–C)
1192Stretchingν(OC–O)
1180Symmetrical stretchingν s(C–O–C)
1162Stretchingν amorphous