Page 493 - Polymer-based Nanocomposites for Energy and Environmental Applications

446 Polymer-based Nanocomposites for Energy and Environmental Applications

extracted from the bioethanol plant was purified by soxhlet extraction for 6 h at 150°C
using a toluene/acetone mixture (2:1 ratio) by eliminating extracts. This material was
then washed with the help of mixture having 700 mL deionized water, 6.7 g sodium
chloride, and 1.5 mL acetic acid, at 70°C for 12 h. Acetic acid and sodium chloride
were consecutively added after every 2 h and stand out for another 12 h, and a pure
white material was developed. After 24 h, the matter was washed with deionized water
and reduced to 17 wt% solid amount by centrifugation. The purified cellulose was
concentrated to 2 wt% suspensions; after mixing with shear mixture, it delivered
by the APV 2000 high-pressure homogenizer (Denmark) at a pressure of 500 bar. This
suspension was homogenized 10 times to get a thick gel of nanocrystalline
cellulose (NCC).

16.2.4 Chitin nanocrystals from carb shell residue

Gopalan Nair and Dufresne [35] were reported the development of chitin nanocrystals
(ChNC). Crab shell residue was subjected to alkali action, acid hydrolysis, and
bleaching. Chitin flakes were boiled, in order to remove proteins, in a 5% KOH solu-
tion for 6 h. After that, hydrolysis of hydrochloric acid (HCl) for 90 min at boiling
temperatures was performed following the bleaching with chlorite for 6 h at 80°C.
Finally, chitin nanocrystal suspensions were developed subsequently after hydrolysis
of acid (3 N HCl) and sonified before applying.

16.3 Preparations of surface modified
bionanocomposites

16.3.1 TEMPO (2,2,6,6, tetramethyl-1-piperidinyloxy)-mediated
oxidation

This TEMPO-mediated oxidation technique was performed like the method
accounted by Saito et al. [36]. In TEMPO-mediated oxidation technique, the cellulose
sludge, slurry was mechanically compressed; latter on it was dispersed in a solution of
NaBr and TEMPO (1 and 0.1 mmol/g of pulp residue, respectively). The concentra-
tion of the pulp residue was adjusted 2 wt% in water. The reaction was carried out by
the addition of NaClO slowly into the suspension following the pH around 10 by
NaOH addition. Thereafter, different oxidation degrees were reached by selecting dif-
ferent quantities of NaClO (1, 3, 6, and 10 mmol/g of pulp residue). Finally, NaClO
was consumed; then, the filtered and rinsed cellulose fibers were mixed in water and
disintegrated in a microfluidizer M-110Y (Microfluidics Ind., the United States) to
develop TOCNF suspension. Likewise, TEMPO-oxidized chitin nanofibers from chi-
tin powder were developed according to the same technique by using 10 mmol/g of
NaClO [37].