Page 679 - Polymer-based Nanocomposites for Energy and Environmental Applications

624 Polymer-based Nanocomposites for Energy and Environmental Applications

acetate nanocomposite foam by melt intercalation method with four organoclays and
found that the glass transition temperature increased by 6–14°C depending on the type
of clay. It was observed that the thermal stability and mechanical properties were also
increased.

23.3.4 Cellulose-based nanocomposites
Cellulose is naturally occurring biopolymer and is available abundantly. Cellulose is
high-molecular-weight polymer and is highly crystalline. Cellulose is converted into
derivative (cellulose ethers and cellulose esters) to make it more processable because
of its infusibility. At present, cellulose acetate is widely used in a variety of applica-
tions ranging from fibers to films. Currently, interest has developed to synthesize
nanocomposites with cellulose materials with enhanced mechanical, thermal, and per-
meability properties. It has been found that the films obtained from nanocomposite
cellulose acetate and organic clay have showed a significant decrease in water vapor
permeability [52]. The interesting results reported by Ruan et al. [53] that the
regenerated cellulose/tourmaline composite films have showed antimicrobial activity
against the Staphylococcus aureus. This could develop a potential use of these films
for packaging materials.

23.3.5 Chitosan-based nanocomposites
Chitosan is the second most abundant naturally occurring biopolymer after the cellu-
lose. It is a partially deacetylated derivative of chitin. This has been extensively stud-
ied for its potential application in industry and packaging production because it is
biodegradable, biocompatible, and nontoxic in nature, but the properties need to be
enhanced by reinforcing with nanoparticles/nanofillers. Lin et al. [54] reported the
preparation of nanocomposites of chitosan/montmorillonite (MMT) by solvent cast-
ing method. It has been observed that when chitosan was incorporated with potassium
persulfate (KPS)-MMT, the tensile properties of nanocomposites largely depend on
the amount of KPS incorporated in the MMT. The more MMT will be exfoliated along
with the degradation of chitosan, which resulted in the increased Young’s modulus,
but the tensile strength decreased. Xu et al. [55] also used the solvent casting method
for the preparation of chitosan-based nanocomposite films with Na-MMT and Cloisite
30B. They found that the nanoclay exfoliated along with the chitosan matrix by addi-
tion of small amount of Na-MMT. It has been also reported that the tensile strength of
these films increased and the elongation at the break decreased with the addition
of clay. Wang et al. [56] used solvent intercalation method for the preparation of
chitosan/MMT nanocomposites. It has been reported that an intercalated/exfoliated
nanostructure was formed with the low content of MMT and also the thermal stability,
hardness, and elastic modulus were improved by increasing the loading of clay in the
matrix. Darder et al. [57] used solution intercalation method for the preparation of
chitosan/MMT nanocomposites with varying amount of clay.