Table 1.

Literature review of the relevant infrared bands associated with different phases of PLLA.

IR frequency (cm−1)	Phase form	Assignment	Ref. No.
860	Amorphous		[30]
871	α		[11, 30]
908	β		[37]
921	α	Coupling of the C–C	[11, 30, 37]
		backbone stretching with
		the CH3 rocking mode
955	Amorphous		[11, 30, 37]
1044	Amorphous, α' and α	ν(C–CH3)	[38, 39]
1053	α	ν(C–CH3)	[6, 38]
1092	α' and α	νs(C–O–C)	[38]
1107	α' and α		[38]
1134	Amorphous, α' and α	rs(CH3)	[38, 39]
1183	Amorphous, α' and α	νas(C–O–C) +ras(CH3)	[38, 39]
1213	α' and α	νas(C–O–C) +ras(CH3)	[38]
1222	α	νas(C–O–C) +ras(CH3)	[6, 38]
1268	Amorphous + semicrystalline	ν(CH)+ν(COC)	[39]
1302	Amorphous	C–H stretching	[11]
1360	Semicrystalline	δ(CH), CH wagging	[39]
		(bending)
1363	Amorphous	δ(CH), CH wagging	[39]
		(bending)
1368	Semicrystalline	δ(CH), CH wagging	[39]
		(bending)
1382	α	δs(CH3)	[6, 37]
1386	α' e α	δs(CH3)	[37]
1387	Amorphous	δs(CH3)	[37]
1444	α	δas(CH3)	[30, 37]
1454	Amorphous	δas(CH3)	[30, 37]
1457	α' and α	δas(CH3)	[30, 37]
1749	α	ν(C=O)	[6, 37, 38]
1757	Amorphous	ν(C=O)	[37]
1759	α	ν(C=O)	[37]
1761	α'	ν(C=O)	[37]
2945	Amorphous	νs(CH3)	[37]
2946	α' and α	νs(CH3)	[37]
2964	α	νs(CH3)	[6, 37]
2995	Amorphous	νs(CH3)	[37]
2997	α' and α	νas(CH3)	[37]
3006	α	νas(CH3)	[6, 37]