Environmental Engineering Reference
In-Depth Information
(a)
(b)
O
O
OH
OH
NH
NH
NH
2
NH
2
O
O
HO
O
HO
O
HO
HO
HO
HO
O
O
O
O
O
O
HN
HN
OH
OH
OH
OH
DDA
O
O
n
DA
FIGURE 20.8
Structure of chitin (a) and chitosan (b).
20.4.2 Functionalization of the Nanofibers
The nanoibers can be functionalized through chemical grafting with bidentate ligands.
The two that have been successfully tried are oxolane-2,5-dione and furan-2,5-dione. The
cellulose nanoibers have been functionalized with oxolane-2,5-dione
73
and chitosan/PAA
nanoibers have been functionalized with furan-2,5-dione. The reaction scheme for the
functionalization of the nanoibers is shown in Figure 20.9.
The morphological structures of the cellulose nanoibers before and after functionaliza-
tion (Figure 20.10) were obtained from SEM, and the iber diameters were measured using
Image Pro Plus 6 software. The average iber diameter have been calculated at 385 nm.
O
(a)
HO
O
OH
(i) C
7
H
8
/C
5
H
5
N; 60°C; 1 h
O
*
O
O
HO
O
O
O
O
(ii) C
4
H
4
O
3
; 90°C; 16 h
HO
OH
n
OH
n
O
O
-
Na
+
(b)
O
O
O
O
O
OH
NH
2
NH
2
O
O
O
O
HO
O
HO
O
O
O
HO
HO
O
1 DMF/Py, 90°C
2 Na
2
CO
3
O
NHCOCH
3
NHCOCH
3
O
HO
O
+
Na
-
O
O
FIGURE 20.9
Functionalization scheme of nanoibers of (a) cellulose with oxolane-2,5-dione and (b) chitosan/PAM with
furan-2,5-dione.
