Table 1. Functional Absorption Bands of DOPO, KH550, and GO in FT-IR.

	functional groups	adsorption bands (cm–1)
DOPO	P–H	ν 2433
	phenyl	ν 1587, 1468
	P–phenyl	δ 1433
	P=O	ν 1238
	P–O–phenyl	ν 1076, 1000
KH550	N–H	ν 3378, δ 1566
	Si–O	ν 1042
	–CH3	ν 2930
	–CH2–	ν 2874
GO	C=O	ν 1727
	C=C	ν 1629
	C–O–C	ν 1398
	C–OH	ν 1056