Cellulose nano-whiskers were extracted and purified from nata-de-coco
(coconut gel) and rendered hydrophobic via two separate methods, which are detailed
in the experimental section: i) via silylation using the reagent
chlorodimethylisopropylsilane [21], and ii) via a greener renewable carbon acetic acid
esterification modification [22, 23]. The authors recognise that the silylation route
involves the non-renewable reactant chlorodimethylisopropylsilane, whereas the
esterification may be regarded as greener since acetic acid is a renewable resource.
However, both modification routes require harmful solvents, such as methanol, THF,
toluene and pyridine, which may be recycled [24]. It is also possible to obviate the
solvent exchange step (involving methanol), which is described in the methodology,
by using freeze-drying the bacterial cellulose after the extraction step