Civil Engineering Reference
In-Depth Information
was produced from ionic liquid treatment of sugarcane bagasse, as presented in
Figure 11.4c [63].
Apart from the production process of NFC by homogenization, their i nal applica-
tion is a critical issue. Because of the hydrophilic nature of cellulose nanoi bers, their
incorporation and dispersion with common polymers, which are hydrophobic, are very
critical issues [38]. Low interfacial adhesion between these two parts in composite leads
to reduction in the mechanical and other properties of the i nal product. h us, a wide
variety of modii cations like carboxymethylation [65], 2,2,6,6-tetramethylpiperdine-
1-oxyl (TEMPO) oxidation [66, 67] , acetylation [68, 69] , and silylation [70, 71] have
been designed to overcome this problem. h e modii cation strategies of cellulose nano-
size materials are discussed in Section 11.6.
11.3.2
Ultrasonication
High-intensity ultrasonication can be considered as a mechanical method for produc-
ing cellulose nanoi bers with hydrodynamic forces [72]. In this process, ultrasonic
waves create strong mechanical stress because of cavitations, and therefore, cause
the disaggregation of cellulosic i ber to nanoi bers [73]. Several attempts have been
made to isolate cellulose nanoi ber by ultrasonication from various cellulose sources
such as microcrystalline cellulose, regenerated and pure cellulose i bers [72] , krat pulp
[74] , l ax, wood, wheat straw and bamboo [75] (Figure 11.5), para rubberwood sawdust
[76], and poplar wood powders [15].
h e well-individualized, web-like structure and long entangled i laments of NFC
from wood (Figure 5a), bamboo (Figure 11.5b) and wheat straw (Figure 11.5c) with
Figure 11.5
Field emission scanning electron microscopoy (FESEM) images of NFC isolated from
(a) wood, (b) bamboo, (c) wheat straw and (d) l ax [75].
