Preparation, Modification, and Application of Starch Nanocrystals in Nanomaterials: A Review

Table 2

Reaction conditions for the “graft to” strategy for starch nanocrystal modification reactions.

Graft polymers	Coupling agents	Solvent	Catalyst	^(a)Reaction temperature	^(a)Reaction time	^(b)Characterization	Ref.
PEGME550	2,4-TDI	Toluene	DTD	70°C	7 days	BET, FTIR, XPS, TEM, CAM	[28]
PPGBE4000	2,4-TDI	Toluene	TEA	70–80°C	7 days	FTIR, XPS, EA, TEM, CAM	[29]
PTHF1400	2,4-TDI (PI capping first)	Toluene	TEA	70–80°C	7 days	FTIR, XPS, EA, TEM, CAM	[29]
PCL10000; PCL42500	2,4-TDI (PI capping first)	Toluene	TEA	70–80°C	7 days	FTIR, XPS, EA, TEM, CAM	[29]
Stearate polymer	stearic acid chloride	Methyl ethyl ketone	TEA	60°C	4 days	BET, FTIR, XPS, TEM, CAM	[28]
^(c)Aliphatic polymers	thionyl chloride	Water	—	20°C	20 min	FTIR, EA, TEM	[30]
ASA350	—	Toluene	4-DAP	70°C	7 days	FTIR, XPS, TEM, CAM	[26]

TEA: triethylamine, DTD: dibutyltin dilaurate, 2,4-TDI: 2,4-toluene diisocyanate, PI: phenyl isocyanate, ASA: alkenyl succinic anhydride, 4-DAP: dimethyl amino pyridine, BET: Brunauer-Emmett-Teller, FTIR: Fourier transform infrared, EA: elemental analysis, TEM: transmission electron microscopy, XPS: X-ray photoelectron spectrometry, and CAM: contact angle measurement. (a)Reaction temperature and time listed in the table are assigned to the temperature and time of modified polymer chains grafted onto starch nanocrystals. (b) Characterization listed in the table refers to the measurements for proving the success of modification. (c) Aliphatic polymers include octanoic (C8), nonanoic (C9) and decanoic (C10) polymers.