| dc.description.abstract |
In the field of material science, various polymers have been reinforced for many years
with either inorganic or organic fillers. The production of polymeric composites with
different types of fillers as reinforcements has gained significant attention. A broad
variety of variations in the characteristics of polymeric composites have been
demonstrated by experimental results from various research groups in the literature.
Epoxy resin, a thermosetting polymer is a prominent class of polymers due to its high
mechnaical strength, high chemical and thermal properties, dimensional integrity,
good adhesion, and solvent resistance. It has a wide spread of applications in the
aerospace, civil, and automobile industries, but its brittle nature and poor toughness
restrict its use in many industries. Its high crosslinked structure is responsible for
epoxy resin’s poor toughness and brittleness. To address these issues, a variety of
fillers have been incorporated within epoxy resin without losing their ability to
perform as intended. Among those fillers, nanomaterials are fascinating yet
challenging materials that improve the brittleness and toughness of epoxy polymers.
They are exciting fillers due to their outstanding physical and chemical characteristics
and large surface area-to-volume ratio. Several investigations have been carried out on
adaptable epoxy nanocomposites based on MWCNT, glass fiber, carbon fiber,
graphene nanoplatelets, carbon nanofiber, fly ash, ZnO, Al2O3, GO, RGO, TiO2, SiO2,
ZrO2, etc. nanomaterials. However, the research studies on carbon nanomaterials and
rare earth metal oxides reinforced epoxy nanocomposites are still very limited.
In this current doctoral work, carbon nanomaterials (MWCNT & RGO) and
rare-earth metal oxide (Y2O3) are used to reinforce with epoxy polymer matrix to
investigate its mechanical, thermal and tribological properties of epoxy
nanocomposites and their hybrids. With the aim to synthesize the epoxy
nanocomposites using carbon nanomaterial and rare earth metal oxide nanomaterial,
firstly pure epoxy polymer has been optimized and their basic characterization like
FTIR, XRD and Raman spectroscopy are done to investigate their chemical bonds and
crystal structure. Also, same characterization is done for all the nanofillers to
investigate their functional groups and chemical bonding. Then the experimental
synthesis parameters are optimized for ultrasonic dual mixing method to fabricate the
epoxy nanocomposites. The effect of different reinforcements in epoxy polymer with
MWCNT, RGO and Y2O3 are further analysed to improve the mechanical, tribological
and thermal properties of fabricated epoxy nanocomposites. The hybrid
nanocomposites by combining these single fillers are fabricated and their exciting and
synergetic properties due to the combination of the constituent properties is
investigated. For mechanical testing static and dynamic mechanical analysis is
investigated and for thermal properties differential scanning calorimetry is used to
v
investigate the glass transition temperature of nanocomposites. Tribological properties
is investigated by wear and friction testing using the Pin-On-Disc instrumentation. The
results of the testing showed that used carbon nanomaterial and rare earth metal oxides
at optimized compositions are successfully improved the properties of the epoxy
polymer.
All optimized nanocomposites are then used to fabricate the similar and dissimilar
adhesive joints at different weights. Adhesive joints are found the most suited joints
for structural applications among all other mechanical joints. Some of the key
advantages that adhesive-bonded joints are believed to offer are excellent corrosion
resistance, notable weight and noise reduction, significant damping capabilities, and
exceptional thermal and insulating properties. The outcomes of this work anticipate
that the similar adhesive lap joint of the mechanically polished aluminium was found
stronger as compared to the mechanically polished steel and the lap shear test results
showed the maximum lap shear strength and % elongation for similar aluminium joints
using pure epoxy adhesives as well as for optimized nanocomposite adhesive than the
similar steel joints and dissimilar ones. Therefore, the synthesized nanocomposites are
useful for the adhesive joints in various structural applications. Thus, the current work
has potential for industrial contributions |
en_US |