1. Presented by : Ajay Kumar
Course : M.sc physics (sem. -3rd)
Registration no. : 16mscphy09
Email : invinciblelangeh9297@gmail.com
Seminar on
Polymer
Nanocomposites
Supervision by :
Dr. Kamesh Yadav
Assistant professor
Centre for physical sciences
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2. CONTENT
Introduction
Advantage of Nanoscale filler over conventional filler
Role of interface between reinforcement and matrix
Surface modification of nanofiller & It’s role
Polymer nanocomposites and it’s synthesis method
- melt compounding
- solvent processing
- in situ polymerisation
Advantages of Polymer NC over conventional composites
Reference
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3. ‘Nanocomposites’ = Nano + Composites
‘Nano’ means very small ratio, billionth part of one
[ 1nano = 10−9
]
‘Composites’ are combinations of more than two,
difference phase materials
What are nanocomposites?
3
4. Nanocomposite is a multiphase solid material where one of the phases
has one, two or three dimensions of less than 100 nanometers (nm).
OR
Structures having Nano-scale
repeat distances between the
different phases that make up
the material.
Definition of Nanocomposites
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5. Major constituent is called Matrix.
Matrix is generally polymer, metal, ceramic etc.
Minor constituent is called Reinforcement
Reinforcement material are nanofiller like nanotubes, nanoplates
(graphene, clay silicates), 0D clusters of 𝑇𝑖𝑂2, 𝐴𝑙2 𝑂3, 𝑆𝑖𝑂2 etc.
NANOCOMPOSITES
MATRIX REINFORCEMENT
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6. Reinforcing Material (any type of nanomaterials)
Source: - http://eng.thesaurus.rusnano.com/upload/iblock/dfc/nanomaterial1.jpg
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7. Advantages of Nanoscale Filler over Conventional Filler
Low-percolation threshold (~0.1–2 vol.%).
Large number density of particles per particle volume
(106–108 particles/µm3
).
Surface area per volume ratio
Area of interface is higher as compared normal composites
Short distances between particles (10–50nm at ~1–8 vol.%).
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8. Both are not in thermodynamic equilibrium at the interface
Discontinuity in elastic moduli, strength, and chemical potential occur
Due to discontinuity, Interphase zone for transition in materials parameters.
Transitions occur gradually over the thickness of the interface.
Source:- https://www.researchgate.net/figure/259996513_fig1_Fig-1-Schematic-representation-of-a-composite-interphase-1
Role of interface b/w matrix and reinforcement
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9. Agglomeration occur due to specific surface area and high surface energy.
Agglomeration overcome by modification of the surface of the nanofiller particles.
Modification improves the interfacial interactions between the inorganic particles
and the polymer matrix.
Chemical
modification
Source:- https://www.slideshare.net/zenziyan/surface-modification-of-nanomaterials
Surface modification
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11. Polymer Nanocomposites
Polymers = Poly + Mers
‘Poly’ means ‘many’ & ‘Mers’ means a ‘units’
Multifunctional features of polymer NC is balance by four independent
areas
Constituent selection
Processing
Fabrication
Performance
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12. Challenges to prepare Nanocomposites
Overcome the huge surface energy, a result of enormous surface
area or large surface to volume ratio
desired size, uniform size distribution, morphology,
crystallinity, chemical composition and microstructure desired
physical properties.
Prevent nanocomposites from agglomeration
Morphology control
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14. Polymer-clay nanocomposites
On the basis of morphology of polymer nanocomposites it is classified as below
source:- http://www.mdpi.com/1996-1944/2/3/992/htm
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15. Morphology
Depending on chemical architecture of surface modifications.
Morphology depends upon the filler content by weight
-Exfoliated nanocomposites less than 15 wt%.
-Intercalated nanocomposites increased from 15 wt%
Morphology also depends upon the temperature on the
polymerization will take place.
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16. Direct Nanofibers addition to the polymer above the glass transition temperature.
Agglomeration is main problem in melt compounding.
Shear stress is induced in the polymer melt by viscus drag.
Shear stress is used to breakdown the nanofiller aggregates
Homogeneous and uniform nanofiller dispersion in the polymer matrix
is due to shear stress.
Melt Compounding
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17. Mixing section of matrix
Strength-controlled agglomerates of
inorganic nanoparticles with high
porosity.
Source:- http://www.particlesciences.com/news/technical-briefs/2011/hot-
melt-extrusion.html
Source:- http://www.particlesciences.com/news/technical-briefs/2011/hot-melt-extrusion.html
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18. Nanoparticles and polymer are dispersed in separate but same solvent
Stirring continuous and then mixed
Nanocomposites are recovered from solvent through solvent evaporation or by the
solvent coagulation method.
Shear stresses induced in the polymer matrix are lowered compared to that in melt
compounding.
The nanofillers are pre-dispersed in the solvent by sonication in order to breakdown
the nanofiller aggregates
Solvent Method
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21. Nanofillers is dispersed in monomer solution
Polymerized either using radiation, heat, initiator diffusion or by organic
initiator
In Situ Polymerisation
Source:-https://www.intechopen.com/books/ion-exchange-technologies/bifunctional-polymer-metal-nanocomposite-ion-exchange-materials
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22. Polymerized between interlayers forming either exfoliated or intercalated nanocomposites.
Polymerisation occur through chemical reaction.
Drawbacks of in-situ polymerization
High temperature synthesis causes decomposition of polymer
Unreacted part influence the properties of final material
Advantages of in-situ polymerization
There is thermodynamic compatibility at the matrix-reinforcement interface
Reinforcement surfaces are free of contamination, strong matrix dispersion bond can be achieved
Insoluble and thermally unstable polymers are used which cannot be processed by solvent and melt
processing. 22
23. Advantages of Polymer NC over conventional polymer composites
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Polymer nanocomposites Conventional polymer composites
In PNC, fillers separation are in nm, properties
will affected by size effects of nanofiller.
In PNC, small amounts of fillers is enough
(less than 10%) , to achieved desired properties.
In PNC, properties obtain without sacrificing
polymer’s inherent properties or adding
excessive weight
Improvements in properties even in low amount
is due to nanosize of fillers & interphase region.
Use of nano sized particles can reduce the
likelihood finding defects, such as grain
boundaries, voids, dislocations and
imperfections as compared.
In this case, fillers are separated in μm, There is no
that much of size effect.
In conventional composites, high concentrations
should be needed as compared to nanofiller case.
Fillers can unfavourably impact other benefits of
polymers such as appearance, ductility and
toughness.
There is no that much of improvement in properties
even for large amount of fillers.
It is difficult even observed in conventional polymer
composites.
