Civil Engineering Reference
In-Depth Information
Table 11.4
Mechanical properties of thermoset polymer matrices-i lled NFC.
Resin
Nano-
cellulose
form
Strength
(Mpa)
Elastic
modulus
(Gpa)
Strain to
failure (%)
Ref.
Epoxy
NFC i lm
(0-5% i ber
content)
1.5-2.9
[191]
Phenol
formaldehyde
MFC i lm
(5-20% wt
i bers)
201-216
4.16 - 4.48
12.6 - 14.7
[193]
Melamin
formaldehyde
NFC (13% wt
i ber)
142
16.6
0.81
[194]
[196] used three general processes, viz., melt blending, grinding, and injection mold-
ing, to produce CNC-polypropylene nanocomposites. Agarwal
et al.
[197] prepared the
nanocomposite from polypropylene reinforced with CNC by extrusion method.
While techniques for preparation of nanocellulose-reinforced nanocomposite are
dif erent in complexity, they typically involve physically mixing and dispersing the
nanocellulose and resin in a solvent system. In many cases, solvent exchange techniques
are used, ot en along with surface modii cation of nanocellulose to make it compatible
with organic solvents and/or the resin system. In this context, nanocomposite i lms
from nanocellulose generally are prepared through three various techniques as below:
1. by casting on Tel on or propylene dishes followed by water evaporation
at moderate temperatures;
2. by freeze-drying and hot-pressing; or
3. by freeze-drying, extruding, and hot-pressing the mixture.
Sehaqui
et al.
[ 198 ] reported manufacturing NFC-reinforced hydroxyethylcellu-
lose (HEC) i lm in a polystyrene Petri dish under air atmosphere at room temperature
with a thickness of 65-80 mm. h e preparation process of the nanocomposite i lm are
illustrated in Figure 11.30 [198].
Gray [199] has studied the transcrystallization of polypropylene at CNC surface.
h ere is a resurgence of interest in composite materials incorporating cellulose as
i brous reinforcement in semicrystalline melt-processed polymers. Potential natural
cellulose sources range from l ax and ramie i bers down to whiskers and nanocrystals
isolated from bacteria (Figure 11.31) [199].
Processing techniques have an important inl uence on the i nal properties of the
nanocomposites based on nanocellulose. h erefore, the achievement of superior
strength in the properties of nanocomposite based on nanocellulose can be used
for many applications. However, the use of nanocellulose as a reinforcement is in its
infancy, and the full reinforcing potential of nanocomposites has yet to be realized
partly because of issues related to scaling up of the manufacturing processes.
Nanocellulose becomes very important because incorporation of nano-reinforce-
ment has been related to improvement in overall performance of nanocomposites.
