Sabu Thomas International and Interuniversity Center for Nanoscience
and Nanotechnology,School of Chemical Sciences Mahatma Gandhi UniversityKottayam, Kerala,India
www.iiucnn.com, www.sabuthomas.com
Advances in the Characterization of Functional Rubber Composites and
Nanocomposites
Potential Nanocomposite Materials
Nano tubes
Graphitic platelets
Nano talc
Meta oxides
Synthetic and natural clays
Bio fibres (flax, hemp…)
Single walled carbon nanotube
RUBBER NANOCOMPOSITES
Polymers comprising particles at least one dimension in the
nanosize range (1-100 nm)
Class of materials that have properties with significant commercial
potential
Attractive features identified with nanocomposites are Efficient reinforcement without loss of ductility and even
improvement in impact strength
Excellent optical and altered electronic properties
Heat Stability
Flame resistance
Improved gas barrier properties
Improved abrasion resistance
Reduced shrinkage and residual stress
Effect of Aspects Ratio- Spherical vs Platy
Aspect ratio 1 10-20 100-200
Viscosity increase Low Low-moderate High
Mechanical
reinforcement
Low Moderate High
Barrier improvement Low Moderate-high High
Dispersibility Moderate-easy Easy Difficult
Structure of layered silicates
Si-tetrahedron
Si-tetrahedron
Mg,Li-Octahedron
1nm
200-
3000nm
High in-plane stiffness
(178 GPa) and strength
High layer aspect ratio
Gallery space 0.96nm
Criteria for Nanocomposites –Structure Influence
Best Properties
8
Typical applications:
• Improving mechanical properties
• Increasing the electrical conductivity
• Increasing thermal conductivity
• Biocide / antibacterial
• UV-absorption
[Gray circles in
the pristine clay scheme
represent the
organomodificant
molecules]
Schematic of
theWAXD
patterns yielded
by different filler
morphologies.
Rubber Nanocomposites, Edited by S.Thomas & R.Stephen
Rubber–Mineral Interface
Lowering the surface energy of the inorganic
silicate
Improvement of the wetting characteristics with the
polymer
Treatment of the silicate surfaces (alkyl
ammonium,..)
Addition of block or graft copolymers as
compatibilizer
In-situ reactive extrusion
Chemical Modification of Clay
Need of chemical modification?
Dispersing layered silicates in a polymer is like trying to mix oil in water
It is for compatibilizing the polymer and the layered silicate
Compatibilizing agents consists of
Hydrophilic function (like polar media
such as water or layered silicates)
Organophilic function (like
organic molecules such as oil
or polymer
Role of compatibilizing agents are similar to detergent
Commonly Used Compatibilizing Agents
Amino acids
Alkylamines
Polyetheramines
Dihydroimidazolines
Silanes
Most widely used are alkylammonium ions- why?
They can easily exchange the inorganic ions situated between the layers
Due to the non-polar nature of their chain, lower the surface energy of the
layered silicate
Reduce the electrostatic interaction between the silicate layers and allow
molecules to diffuse between the layers
Organic Modification and Shift in d-spacing of Clay
WAXs of MMT clays
12ALA- 12-aminolauric acid –
1°alkylammonium
DOA-dioctylamine-2°alkylammonium
TOA- trioctylamine-3°alkylammonium
Cloisite Na+- Natural MMT
Cloisite 30B and Cloisite 20A- Organic treated MMT
14
All loading show intercalated
morphology but the (002) peak
in CIIRN10 is higher than other
loading which indicates an
agglomerated morphology.
These results are confirmed
by the HRTEM images of CIIR
and NR nanocomposites
WAXD pattern of NR/nanoclay and Chlorobutyl nanoclay composites
15
XRD pattern of 50/50 NR/NBR rubber blends with different clay loading
Higher filler loaded samples indicate the presence of intercalated
aggregate structure
Maria, H.J., Lyczko, N., Nzihou, A., Joseph, K., Mathew, C. and Thomas, S., 2014. Applied Clay Science, 87, pp.120-128.
16
2D SAXS images of EVA/clay nanocomposites. (a) 7 wt % Cloisite20A clay loading, C7 sample (b) 7 wt % Cloisite25A
clay loading, D7 sample. (c) azimuthal plot I(u) versus u for C7 (solid line) and D7
2D – SAXS imaging of EVA clay Nanocomposite
Wilson, R., Plivelic, T.S., Aprem, A.S., Ranganathaiagh, C., Kumar, S.A. and Thomas, S., 2012. Journal of applied polymer
science, 123(6), pp.3806-3818
Influence of nanoclay loading on the Storage modulus (G’)
of (a) natural rubber nanocomposites and (b) chlorobutyl
rubber nanocomposites at 160 C.
Rheological behaviour of clay incorporated natural rubber and chlorobutyl
rubber nanocomposites
Zachariah, A.K., Geethamma, V.G., Chandra, A.K., Mohammed, P.K. and Thomas, S., 2014. Rheological behaviour of clay incorporated natural
rubber and chlorobutyl rubber nanocomposites. RSC Advances, 4(101), pp.58047-58058.
17
The effect of amplitude dependence on the dynamic viscoelastic properties
of filled rubbers is referred to as the Payne Effect. (Payne, A. R. J. Polym.
Sci. 1962, 6, 57).There is a decrease in dynamic storage modulus of filled
elastomers with increasing deformation amplitude. (Fletcher and Gent,
1953)
Payne Effect
Payne Effect (Schematic representation)
Kraus (1984) proposed an empirical model based on the agglomeration/deagglomeration kinetics of filler aggregates,assuming a van der waal’s type interaction between the particles
Schematic representation of filled elastomeric network
Payne Effect
Yves Grohens et al Nonlinear Viscoelastic Behavior of Silica-Filled Natural Rubber Nanocomposites
J. Phys. Chem. C 2009, 113, 17997–18002
19
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6G
' (
MP
a )
0.12 4 6 8
12 4 6 8
102
g (%)Liquid-like
Strongly
aggregated
Weakly aggregated
Particles arrangement
20
Comparison of tan δ, hysteresis property and rolling resistance between a
carbon black
and a silica filled rubber for tire application. (A: temperature dependence
of tan δ, B: strain
dependence of G", the Payne effect)
Comparison of hysteresis property and rolling
resistance
Nanocomposites in Tyre industry
MAGIC TRIANGLE OF TYRE
PERFORMANCE
Traction avoid slippage while running on the road,
Abrasion resistance low wear and good durability,
Rolling resistance affects fuel consumption.
Nanofillers enable the best balance of these three parameters.
NR/Silica nanocomposites
Strain dependence of the storage modulus
(E0-E∞) increases with increase in
silica content
24
1E-3 0.01 0.1 1 10 100
0.4
0.8
1.2
1.6
2.0
2.4
2.8
% Strain
E' (
MP
a)
NR
NRS5
NRS10
NRS15
NRS20
AP Meera, S Said, Y Grohens, S Thomas J. Phys. Chem. C 2009, 113, 17997–18002
1E-3 0.01 0.1 1 10 100
0.04
0.08
0.12
0.16
% Strain
E''
(M
Pa)
NR
NRS5
NRS10
NRS20
Strain dependence of loss modulus
Strain
Rubber chain segments
Silica aggregate
(a)
(b)
Schematic representation of (a) the breakdown of aggregates and desorption of rubber chain
segments from the filler surface in silica filled NR system (b) multiple points of attachments of
rubber chains at the silica surface converting to the single points of attachments on straining.
25
AFM height image of NR filled with 20 phr
nanosilica
AP Meera, S Said, Y Grohens, S Thomas J. Phys. Chem. C 2009, 113, 17997–18002
Effect of temperature on the Payne effect
1E-3 0.01 0.1 1 10 100
0
1
2
3
4
5
E
' x 2
73/T
(MP
a)
% Strain
248 K
263 K
303 K
373 K
NR/Silica composites
The amplitude of the Payne effect decreases dramatically
with temperature 26 AP Meera, S Said, Y Grohens, S Thomas J. Phys. Chem. C 2009, 113, 17997–18002
Effect of Temperature
0.01 0.1 1 10 100
0
1
2
3
4
5
% Strain
E'x
273
/T (
MP
a)
● 248 K ▲263 K ▼303 K 373
K
NR/Silica
composites
The solid lines represent the curve fits according to the model 27
28
Strain dependence of the storage modulus (fitted with the Maier and Göritz model) for a) neat PU, b) PG0.5, c) PG1.5 and d) PG3 at
different temperatures of 298 K, 323 K and 348 K.
Payne effect analysis of polyurethane / Graphene oxide composites
Ponnamma, D., Sadasivuni, K.K., Strankowski, M., Moldenaers, P., Thomas, S. and Grohens, Y., 2013.Rsc Advances, 3(36), pp.16068-16079.
Dynamic Mechanical Characteristics of Ionic Liquid Modified MWCNT -SBR
Composites
Abraham, J.; Thomas, J.; Kalarikkal, N.; George, S. C.; Thomas, S.. J. Phys. Chem. B 2018, 122 (4), 1525–1536 29
Viscoelastic Behavior and Reinforcement Mechanism in Rubber Nanocomposites in the Vicinity of Spherical Nanoparticles , P. Bindu and Sabu
Thomas J. Phys. Chem. B 2013, 117, 12632-12648
.
(a) Schematic of the core-shell morphology of rubber-
nano ZnO nanocomposites. (b) Schematic of the
distribution of spherical nanofiller (nano ZnO) in the
rubber matrix Plot of Cv vs nano ZnO content (wt %).
Rubber-nano Zno Nanocomposites.
30
a
b
SEM images of the (a) 70/30 and (b) 50/50 NR/NBR blend with dispersed and co- continuous morphology.
Morphology – Scanning Electron Microscopy
Result & discussion
50/50 NR/NBR blend with 0 clay
70/30 NR/NBR blend with 0 clay
Dispersed phase of
NBR NBR phase with co-
continous and
dispersed phase
morphology.
31
c)
b) a)
e)
The change in morphology of 50/50
NR/NBR nanocomposites with
increase in nanoclay loading
a),b),c) &d) corresponding to the
blend nanocomposites with 0,2,5 and
10phr clay respectively.
Morphology – Scanning Electron
Microscopy
Result & discussion
e) Schematic showing the change in
morphology of 50/50(0) from cocontnious
into dispersed morphology on adding clay.
The decrease in
phase size with the
addition of
(O1MT) Cloisite
10 A clay
1phr clay 2phr clay
5phr
clay
10 phr clay
D D
D D
32
34
CB distribution in NR /SSBR rubber blends
Henning et.al ,MICROMECHANICS OF POLYMERS 25th Polychar 2017
AFM phase image of 50XNBR-50NR blend with 8 phr of
Cloisite 15A
AFM phase image of 50XNBR-50NR blend (b) AFM-Raman spectra of
NR phase (red colour) and XNBR phase (blue colour) in 50XNBR-50NR
blend
Satyanarayana, M.S., Bhowmick, A.K. and Kumar, K.D., 2016 Polymer, 99, pp.21-43. 35
Raman Imaging of XNBR – NR blends
-1 0 1 2 3 4 5 6 7 8 9 10 11
0
10
20
30
40
50
60
70
80
90
100
110
GT
RX
10
2(c
c/m
2xdayxatm
)
Amount of filler (phr)
100 CIIR
70 CIIR
Nitrogen Impermeability
Comparison of Nitrogen Permeability of 70Chlorobutyl Rubber /30 Natural Rubber nanocomposites with Chlorobutyl Rubber
Nanocomposites with Nanomer I.44P
Absolute Values of Nitrogen Permeability in
Nanocomposites with Closite 10A
• CIIR neat - 73.73
• NR Neat- 210.67
• CIIR/2.5 Closite 10A- 56.43
• CIIR/5.0 Closite 10A- 61.47
• CIIR/7.5 Closite 10A-91.45
• CIIR/10 Closite 10A-79.21
• 70CIIR/30 NR- 100.43
• 70CIIR/30NR 5Closite10A- 50.23
• 70CIIR/30NR 7.5 Closite 10A- 53.29
• 70CIIR/30NR 10 Closite 10A- 74.78
CNT/NR Nanocomposites
Compo.Stru., 75, 2006, 496
By increasing the amount of CNT, the orientation become more randomize
The storage modulus vs. strain amplitiude for MWCNT-filled NR films
Measured at room temperature
S Bhattacharyyaa, C.Sinturela, O. Bahloula, M.Saboungia,S. Thomas, J. Salvetata , C arbon 4 6 ( 2 0 0 8 ) 1 0 3 7
TEM images of activated CNTs
Resistivity vs. CNT volume fraction, showing
an electrical percolation behavior due to CNT
network formation.
NRL/Carbon Nanotube Composites
(Electrical Conductivity )
S. Thomas et al. Carbon 46 (2008) 1037-1045
Part-I Part-II Part-III Part-IV Conclusions
42
Reinforcement Of Natural Rubber By Networking of Activated
Carbon Nanotubes
Improving reinforcement of natural rubber by networking of activated carbon nanotubes Sanjib Bhattacharyyaa, Christophe
Sinturela…..Sabu Thomasb, Jean-Paul Salvetat Carbon Volume 46, Issue 7, June 2008, Pages 1037–1045 43
Stress-strain curves of SBR/ CNT nanocomposites with Stress-strain curves of SBR nanocomposites with various ionic
liquid concentration
Stress-strain relationship
Abraham, J., Xavier, P., Bose, S., George, S.C., Kalarikkal, N. and Thomas, S., 2017. Polymer, 112, pp.102-115.
44
Well-organized interconnected RGO networks throughout the
NR matrix, which played an important role in determining the
properties of composites Effective Interfacial Stress Transfer From
NR Matrix To RGO Sheets Imparted By
Gelatin.The Composites Exhibited An
Excellent Stretchability Without Rapid
Fracture.
RGO nanosheets were wrapped around
NRL particles to form an interconnected
weblike networks.
Dong, B., Wu, S., Zhang, L., & Wu, Y. (2016). Industrial & Engineering Chemistry Research, 55(17), 4919-4929.
Ionic liquid Modified MWCNT SBR Soft Nanocomposites for EMI shielding
Transmission microscopy images of
unmodified and modified
composites(A) T3 IL0 (B) T3 IL1 (C)
TEM image of modified MWCNT
Thomas et al. J. Mater. Chem,,in
Press, RSC Advnces, PCCP
RSC Advances, 2016, PCCP, 2016
(A) Total shielding effectiveness as a function of frequency for composites with different MWCNT loadings
(B) with IL loading (C) Electrical conductivity at 1 KHz and the average SET at different bands vs. concentration
of f-MWCNTs. Thomas et al. J. Mater. Chem,, in Press, RSC Advances, 2016, PCCP, 2016
Transmission electron micrographs from a dilute suspension
of hydrolyzed (a) tunicin, (b) wheat straw, (c) cotton, (d)
sugar-beet pulp, (e) squid pen, (f) Riftia tubes, (g) crab shell,
and (h) waxy maize.
Courtesy: Alain Dufresne, ICBC 2005, M.G University, Kottayam
SPM – Acid Hydrolysed fibrils,
Banana fiber
Phase SPMs by Multimode SPM with a Nanoscope IV
controller in tapping mode , Thomas et al. Biomacromolecules
ESEM image of acid treated
PALF fibre
Carbohydrate Polymers 86,
no. 4 (2011): 1790-1798.
The drop in pressure facilitates the increase in the fibrillation process of the PALF fibers whose size ranges in nanometers
Tensile tests performed at room temperature on pure P(S-BuA) rubber
matrix and related cellulose filled composites
Logarithm of the normalized storage shear modulus (log G'T/G'200, where
G'200 corresponds to the experimental value measured at 200 K) vs.
temperature at 1 Hz for tunicin whiskers reinforced poly(S-co-BuA)
rubber nanocomposite films.
56
Nano Mechanical Analysis
Load – Displacement curves of PDMS – clay composites
Charitidis, C.A. and Koumoulos, E.P., 2012. Plastics, Rubber and Composites, 41(2), pp.88-93.
Application of loads from 1 to 10
000 mn and the recording of
penetration depths as a function of
applied loads with a high load
resolution (1nN) and a high
displacement resolution (0.04 nm).
International and Inter University Centre for Nanoscience and Nanotechnology
Pressure Tactile Sensor:
In a pressure tactile sensor, the pressure applied on the surface of the sensor changes either the electric property (piezoelectricity) or resistance of the material, thereby exhibiting the touch characteristics.
Materials used-
Polymer- poly(isobutylene-co-isoprene) (IIR)
Fillers- RGO and expanded graphite (EG)
Weight %- 5
Method- Solution mixing
Kishor Kumar Sadasivuni et al Materials Letters 96 (2013) 109–112
International and Inter University Centre for Nanoscience and Nanotechnology 58
-0.05 -0.06 -0.07 -0.08 -0.09 -0.10
-0.1
-0.2
-0.3
-0.4
-0.5
Max R
ela
tive R
esis
tan
ce (
AR M
ax)
Force (kN)
IIRRGO
IIREG
Linear Fit
Pressure Sensing
+
-
The resistivity change is explained by construction and destruction of conductive networks. The relative resistance AR of IIR-RGO composite changes linearly with pressure unlike IIR- EG IIR–RGO has potentiality as flexible force sensor.
Kishor Kumar Sadasivuni et al Materials Letters 96 (2013) 109–112
International and Inter University Centre for Nanoscience and Nanotechnology
Thomas et a.l Materials Letters 96 (2013) 109–112, Progress in
Polymer Sci, 2015
0 100 200 300 400-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
Fore
ce
(kN
)
A
R
Time (sec)
AR -0.08
-0.06
-0.04
-0.02
0.00a)
Force (kN) 0 100 200 300 400-0.5
-0.4
-0.3
-0.2
-0.1
0.0
Fo
rce
(k
N)
AR
Time (sec)
AR -0.08
-0.06
-0.04
-0.02
0.00b)
Force (kN)
AR of the samples decrease with pressure at successive double cycles
of measurements (negative pressure coefficient of resistance).
The electrical resistance of RGO filled rubber composite changes
regularly with uniaxial pressure due to the large number of contacts
between RGOs (nano-confinement).
IIR/EG IIR /RGO
Pressure Sensing….
International and Inter University Centre for Nanoscience and Nanotechnology
Organic Solvent Sensing
•The solvent sensitivity of NR composite samples were noted from the sudden variation in electrical
conductivity which was due to the breakdown of the filler networks during swelling in different
solvents.
•It is concluded that the polarity induced by RGO addition reduces the interactions between CNTs and
ultimately results in the solvent sensitivity.
Materials used-
Polymer- Natural Rubber (NR)
Fillers-CNT, RGO sheets (thermally reduced at temperatures of 200
and 600 0C )
Weight %- 5
Method- Solution mixing
Deepalekshmi Ponnamma et al Soft Matter, 2013, 10.1039/C3SM51978C
International and Inter University Centre for Nanoscience and Nanotechnology
Organic Solvent Sensing….
Deepalekshmi Ponnamma et al Soft Matter, 2013, 10.1039/C3SM51978C
•The experimental set up for the tests reveals solvent injection on the film surface.
•It was found that the synergy between CNTs and RGO exfoliated at 200° C imparts maximum sensitivity to NR in recognizing the usually used aromatic laboratory solvents.
•The electrical resistance is found to vary for the organic solvents used, toluene, p-xylene and benzene.
Experimental setup for solvent sensing in a closed chamber (a) and the electrical
resistance variation with solvents toluene (b) p-xylene (c) and benzene (d) for
composites.
International and Inter University Centre for Nanoscience and Nanotechnology
Dual Phase Sensing
Kishor Kumar Sadasivuni et al Material Chemistry and Physics, 10.1016/j.matchemphys.2014.06.055
Materials used-
Polymer- poly(styrene-isoprene-styrene) (SIS)
block copolymer
Fillers-PANI
Weight %- 5- Method- in situ polymerization
in the presence of doping agent
•Here we propose oil sensors made of polyaniline (PANI) filled
SIS composite films
•The changes in resistivity of the samples in presence of both
oil and water media reveal good sensing ability of SIS-PANI
films towards oil in water (dual phase).
International and Inter University Centre for Nanoscience and Nanotechnology
Dual Phase Sensing….
•The relative resistance of the SIS-PANI thin film
sensors increases slowly when exposed to oil,
and then reaches towards a constant value with
time.
•The relative resistance of the SIS-PANI sensors
varies upon the exposure to water medium
where the change is drastic and the resistance
value shows a decrease trend different from the
previous case.
•For oil in water medium, the relative resistance
first decreases and then increases.
Kishor Kumar Sadasivuni et al Material Chemistry and Physics, 10.1016/j.matchemphys.2014.06.055
Relative resistances (DR/R0) vs time (min) for SIS-PANI composite
films in different media a) oil b) water and c) oil in water.
CNT@CNC/NR Strain sensor
• CNT@CNC (1/1 wt%)
nanohybrid suspension.
• 1.2, 2.0, 2.8, 3.5 and 4.2
S. Wang et.al Soft Matter, 2016, 12, 845--852
• CNT@CNC/NR percolation
threshold (1.6 vol%)
• 4-fold lower than that of the
CNT/NR (7vol%)
• CNT@CNC/NR-2.8 is 9
orders magnitude of
CNT/NR
S. Wang et.al Soft Matter, 2016, 12, 845--852
Electrical conductivity
No significant effect on aspect ratio of CNC
RGO@CNC/NR Chemical sensor
• 1, 2, 3, 4 and 5 phr of
RGO
RGO RGO/C
NC RGO/C
NC RGO
J. Cao et al. Carbohydrate Polymers 140 (2016)
88–95
• RGO@CNC/NR nanocomposites is
only 0.66 vol %
• RGO /NR 1.7 vol%
Electrical conductivity Tensile Properties
J. Cao et al. Carbohydrate Polymers 140
(2016) 88–95
Responsivity–Time relationship
Exposed to toluene During five immersion drying runs
RGO@CNC/NR RGO/NR
J. Cao et al. Carbohydrate Polymers 140
(2016) 88–95
RGO@CNC/NR2.
08
CONCLUSON MULTIPLE TECHNIQUES
-Rheometery(rotational/capillary)
-Microscopy(OM, SEM, TEM, AFM)
-Spectroscopy(NMR, FTIR, Raman,FS, UV..)
-X-ray-WAX/SAXS
-DMA, TMA, DSC, TGA
-Dielectric measurements
-Mechanical measurements (static and dyamic)
-Zeata potential
-Flammability
-Permeability
-EMI shielding
Acknowledgements
PhD Students/Post Docs
Siby, Deepa, Kishore, Ajesh, Rani, Visak, Jiji, Hanna, Eldhow,
Runcy,Visak,Meera, Bindu, Srinivas
Government Funding
DST, Nanomission (Prof. CNR Rao)
ISRO, CSIR, DBT, AICTE, UGC, DRDO, DIT, TWAS,BRNS
Industrial Funding
Du Pont, USA, General Cables, USA, Surface treat, Czech
MRF Tyres, Apollo Tyres, India
Collaborators
Dr.Jurgen Pionteck, Dresden, Germany
Plivelic, T.S., Italy
Aji P Mathew, University of Stockholm. Sweden
Prof. Paula Mouldnaers. KUL, Belgium
Prof. Yves Grohens, Uni of South Brittany, France
71
School of Chemical Sciences
Centre for Nanoscience
“The aim of University education should be to turn out true servants of the people, who would live and die for the country’s freedom” – Mahatma Gandhi
Welcome to
INTERNATIONAL CONFERENCE ON NATURAL POLYMERS
Venue :MAHATMA GANDHI UNIVRSITY CAMPUS.
Kottayam, KERALA,INDIA
Date: December 7-9, 2018
Website: [email protected]