Civil Engineering Reference
In-Depth Information
and BC nanoi brils (Figure 2.13) [113]. h e i lms were highly transparent, l exible and
showed better mechanical properties than the uni lled chitosan ones. h ese notable
properties are promising for application in biodegradable and antibacterial packaging
as well as in medical and electronic devices.
Lin
et al.
[110] developed porous BC/chitosan nanocomposite membranes pre-
pared by immersing BC membranes in a chitosan solution followed by freeze-drying.
Histological examinations revealed that wounds treated with these BC/chitosan mem-
branes epithelized and regenerated faster than those treated with pure BC membranes
and therefore are considered as potential candidates for wound dressing materials.
In a distinct vein, BC/chitosan membranes have been tested for pervaporative separa-
tion of binary aqueous-organic mixtures (ethanol/water) [111]. h e substantially high
pervaporative separation index (350 kg.
.m
-2
.h
-1
) and low activation energy (10 kJ.mol
-1
)
are indicative of the high potential of BC/chitosan membranes in the pervaporative
separation of ethanol/water azeotrope. Targeting to mimic the intrinsic antimicrobial
properties of chitosan on BC nanoi brils, nanostructured BC nanocomposite mem-
branes were obtained by surface functionalization with aminoalkyl groups (Figure 2.14)
[114]. h ese bioactive nanostructured membranes also presented improved mechani-
cal and thermal properties and may be useful for biomedical applications.
Starch is one of the most abundant natural polymers and is considered as a git ed
raw material for the development of novel biobased and innovative materials, including
composites. Starch granules are simply converted into a thermoplastic material, com-
monly designated as thermoplastic starch, by disruption of the molecular chain interac-
tions under specii c conditions of temperature and mechanical shear and in the presence
of a plasticizer [115, 116]. When thermoplastic starch is mixed with BC its mechani-
cal properties are considerably improved [117-120], indicating a good compatibility
between the two polysaccharide chains and supporting the excellent mechanical rein-
forcement potential of BC. Apart from the enhanced mechanical properties of these
BC/thermoplastic starch nanocomposites, signii cant improvements in the water
resistance and thermal stability are also typically observed. BC/thermoplastic starch
μ
Degassing
Chitosan solution
1.5% (v/w)
Dispersion
Ultra-Turrax
BC (up to 40%)
HCH
HCHBC 10
Casting
ventilated oven
Figure 2.13
Schematic representation of the preparation of transparent i lms based on BC and chitosan.
Reproduced with permission from [113].
