Page 49 - Polymer-based Nanocomposites for Energy and Environmental Applications

28 Polymer-based Nanocomposites for Energy and Environmental Applications

TM tensile modulus
UPE unsaturated polyester resin
VR vinyl ester resin
WF wood fiber

2.1 Introduction

A composite is a structural material that consists of two or more combined constitu-
ents. They are combined at a macroscopic level and are not soluble with each other.
One constituent is called the reinforcing phase, and the other embedded one is called
the matrix. The reinforcing phase material is in the form of fibers, particles, or flakes.
The matrix phase materials are generally continuous one. Combining two or more
materials together to make a composite is worthier than just by using traditional mono-
lithic metals such as steel and aluminum. Monolithic metals and their alloys do not
always meet the demands of today’s advanced technologies. Hence, only by combin-
ing several materials, it meets the required performances.
In many cases, fiber-reinforced composites are more efficient. For example,
highly competitive airline market, continuously looks for the ways to lower the over-
all mass of the aircraft without decreasing the stiffness and strength of its compo-
nents. This is possible by replacing conventional metal alloys with composite
materials. Even if the composite material cost is higher, the reduction in the number
of parts is an assembly, and the savings in fuel costs make them more profitable.
Reducing 0.453 kg of mass in a commercial aircraft saves up to 1360 L of fuel
per year; fuel expenses of the total operating costs of a commercial airline are
25%. Composites offer several other advantages over conventional materials. These
materials improve the strength, stiffness, fatigue and impact resistance, thermal con-
ductivity, corrosion resistance, etc.
Recently, nanoreinforcement of polymers to form nanocomposites has attracted the
attention of researchers for their potential in property development. Organically,
unmodified and modified nanoclay, nanofiber, or carbon nanotubes having ultrahigh
strength and stiffness have become very popular during the last decade for
nanoreinforcement of polymers. Their nanoscale dimensions contribute enormous
rheological benefits to the polymer resin systems. Nanoparticles at very low concen-
tration (<5 wt%) are dispersed in polymer resins, and they often impart superior
mechanical, thermal, barrier, and electromagnetic properties. So, nanoreinforcement
of polymer has opened up a new horizon for different property developments and their
potentials in structural applications. Polymer nanocomposites are relatively the new
type of composite materials, of which the possibilities are numerous, but they are not
fully explored.

2.1.1 Nanoscience and nanotechnology
Nanotechnology is the advanced technology, that deals and describes the design, pro-
duction, characterization, and application of nanobased materials and systems [1,2].
The term “nanotechnology” was invented by Taniguchi in 1974 and defined as “the