vi 3.9.2 Accelerometer Free Vibration Test - Logarithmic
Decrement Method 86
3.9.3 Measurements of Vibration Damping Properties 88
4. RESULTS AND DISCUSSIONS
90
4.1 Stage 1: Production of the Optimum Formulation of
NREPDM Blends 90
4.1.1 Modelling Summary 91
4.1.2 Interaction between Variables for Cure Characteristics of the Blends
92 4.1.3 Interaction between Variables for Tensile Properties of
the Blends 96
4.1.4 Experimental Analysis on NREPDM blends 100
4.1.4.1 Swelling Behavior 100
4.1.4.2 Differential Scanning Calorimetry DSC Analysis
101 4.1.4.3 Scanning Electron Microscopy SEM Analysis 103
4.2 Stage 2: Facile Method for Surface Treatment of
GNPs-Chitosan 105
4.2.1 Selection of Dispersant through Experimental Study 105 4.2.2 FTIR Analysis of Noncovalent Functionalization of
GNPs by Chitosan 110
4.2.3 Proposed Reaction Mechanism 113
4.3 Stage 3: Characterization studies on NREPDM filled
graphene composites 114
4.3.1 Curing Characteristics 114
4.3.2 Tensile Strength Ts 118
4.3.3 Modulus at 100 M
100
and 300 M
300
Elongation 120
4.3.4 Elongation at break E
b
122 4.3.5 Swelling Measurement
124 4.3.6 Structural Analysis
126 4.3.6.1 Fourier Transform Infrared Spectroscopy
FTIR Analysis 126
4.3.6.2 X-Ray Diffraction XRD Analysis 129
4.3.7 Scanning Electron Microscopy SEM Analysis 134
4.4 Stage 4: Determination of Vibrational Damping Properties
137 4.4.1 Determination and Selection of Samples using
Response Surface Methodology 137
4.4.2 Vibration Test Free Vibration Mode- Logarithmic Decrement Method
137 4.4.3 Dynamic Mechanical DMA Analysis
142 4.4.4 Transmission Electron Microscopy TEM
146
5. CONCLUSION AND RECOMMENDATIONS
148
5.1 Conclusion
148 5.3
Recommendations for Future Work 152
REFERENCES 154
vii
LIST OF TABLES
TABLE TITLE
PAGE 2.1
2.2 2.3
2.4 2.5
2.6 3.1
3.2 3.3
3.4 3.5
3.6 3.7
3.8 3.9
3.10 3.11
3.12 3.13
3.14 3.15
3.16 Typical property ranges of EPDM
Applications for EPDM Impact of filler parameters on the properties of filled rubber
material Properties of GNPs and CNTs
Level of sulphur and the ratio of accelerator to sulphur List of published studies on polymer using RSM
Properties of NR SMR 20 Properties of EPDM
Properties of ENR-50 Properties of sulphur system
Properties of accelerator Properties of 6PPD anti-oxidant agent
Classification of raw material General properties of graphene nanoplatelets KNG-150
General properties of chitosan General properties different types of solvents
Levels of variables 2
4
Factorial design matrix used for the screening factors Experimental matrix and the output response table
Typical formulations Compounding formulation used in NREPDM filled with
unfunctionalized and functionalized GNPs Factors and the constraints on the responses for the selection of
the worst, middle and best samples 18
19 26
31 44
51 54
55 56
57 58
59 60
61 62
63 74
75 76
77 83
85
viii 4.1
4.2 4.3
4.4 4.5
4.6 Regression equations for different responses
Comparisons of experimental and predicted tensile strength values of NREPDM blends
DSC results obtained for neat rubbers with their blends The observation of the 2 hour of sonication time
FTIR spectra evaluation for non-covalent treatment of GNPs Log decrement values and damping ratios of GNPs filled
NREPDM nanocomposites 93
99 102
106 110
141
ix
LIST OF FIGURES
TABLE TITLE
PAGE 2.1
2.2 2.3
2.4 2.5
2.6 2.7
2.8 2.9
2.10 2.11
2.12 2.13
2.14 2.15
2.16 2.17
2.18 2.19
2.20 2.21
2.22 Schematic of elastomeric networks under tensile deformation
Chemical formula of natural rubber Ozone cracking on side wall of tire
Various applications of NR Chemical structure of ethylene-propylene diene rubber EPDM
Interface between miscible and immiscible of polymer blends General schematic of epoxidation on NR latex
Payne effect of filled rubber Stress softening of filled rubber also known as Mullins Effect
Layered graphite tightly bonded in hexagonal rings Schematic illustration of GNP production
Mechanism of ultrasonication Chemical modification of graphene
Schematic of grafting-to and grafting-from approaches Schematic representation of non-covalent functionalization of
GO through surfactants, polyelectrolytes, polymers and DNA Solvent casting methods for the preparation of GNPs-polymer
The mechanism of FGS incorporation into polymer for melt blend technique
Reaction of sulphur vulcanization Different crosslink structures:a monosulfidic, b disulfidic,
c polysulfidic, when x = 3-6, d pendant sulphide, e cyclic monosulphide, f cyclic disulphide
Rheometer curve Elements of a vibratory system
Summary of RSM analysis flow 13
14 16
16 17
22 23
27 27
28 29
32 34
35 37
39 41
42 43
45 47
49
x 3.1
3.2 3.3
3.4 3.5
3.6 3.7
3.8 3.9
3.10 3.11
3.12 3.13
3.14 3.15
3.16 3.17
3.18 3.19
3.20 3.21
3.22 3.23
3.24 3.25
3.26 4.1
Flowchart of the overall experiment Masticated NR
Masticated EPDM Masticated ENR-50
a Stearic scid b Zinc oxide and c Sulphur a Perkacit MBTS b Perkacit TMTD
6PPD anti-oxidant agent Commercialize graphene nanoplatelets KNG-150
Chitosan a Dumbbell die cutter b Dumbbell-shaped samples size for BS
6747 Universal testing machine Toyoseiki Strograph
Photograph of swelling measurements of NREPDM filled GNPs samples
a Fourier transform infrared FTIR-6100 JASCO b thin film of sample for ATR-FTIR
Schematic illustration of an X-ray diffraction setup Schematic illustration of diffraction according to Bragg’s law
Panalytical XPert PRO diffractometer machine Differential scanning calorimetric DSC
Transmission electron microscopy TEM Haake rheomix OS internal mixer machine
NREPDM blends product from internal mixer The compounding sample placed in the mold
a GT 7014 - A hot press machine and b Example of vulcanized sample
a Ultra-sonication setup b Sonicator dispersing GNPs Logarithmic decrement method free vibration of a damped single
degree of freedom system Shape and dimensions of test specimen for the measurement of
the vibration damping properties
Test set-ups for free vibration test Response surface plot showing variation in a scorch time
ts
2
; b cure time t
90
; c maximum torque M
H
and 53
54 55
56 57
58 59
61 62
65 66
67 69
69 70
71 72
73 78
78 79
80 81
87 88
89
xi 4.2
4.3 4.4
4.5 4.6
4.7 4.8
4.9 4.10
4.11 4.12
4.13 4.14
4.15 4.16
d torque difference M
H
– M
L
Response surface plot showing variation in a tensile strength Ts; b modulus at 100 elongation M
100
, c modulus at 300 elongation M
300
and d elongation at break E
B
The swelling percentage and crosslink density of the NREPDM blends
DSC thermograms of neat rubbers with R0, R15 and R10 SEM micrographs showing tensile fracture surface of
NREPDM blends at 7030 blend ratio: a R0 b R15 c R10 at 300X magnifications
TEM image of the graphene dispersed with different solvents: a ethanol and b toluene
FTIR spectra of chitosan, GNP, GNP functionalized chitosan Noncovalent functionalization of GNPs through amide linkage
with the chitosan Effect of unfunctionalized and unfunctionalized GNPs loading on
the scorch time ts
2
of NREPDM nanocomposites Effect of unfunctionalized and functionalized GNPs loading on
the cure time t
90
of NREPDM nanocomposites Effect of unfunctionalized and functionalized GNPs loading on
the maximum torque M
H
of NREPDM nanocomposites Effect of unfunctionalized and functionalized GNPs loading on
the torque difference M
H
-M
L
of NREPDM nanocomposites Effect of unfunctionalized and functionalized GNPs loading on
the tensile strength Ts of NREPDM nanocomposites Effect of unfunctionalized and functionalized GNPs loading on
modulus at 100 elongation M
100
of NREPDM nanocomposites
Effect of unfunctionalized and functionalized GNPs loading on modulus at 300 elongation M
300
of NREPDM nanocomposites
Effect of unfunctionalized and functionalized GNPs loading on the elongation at break Eb of NREPDM nanocomposites
95 97
100 103
104 109
112 113
115 115
116 117
119 120
121 122
xii 4.17
4.18 4.19
4.20 4.21
4.22 4.23
4.24 4.25
4.26 4.27
4.28 4.29
4.30 Schematics of tensile fractured mechanism of a neat
NREPDM; b a NREPDM nanocomposite at lower GNPs loading; and c a NREPDM nanocomposite at a higher GNPs
loading overloading Effect of GNPs loading on the swelling behaviour of NREPDM
blends filled unfunctionalized and functionalized GNPs ATRIR spectra of vulcanized NREPDM blends and NREPDM
filled unfunctionalized GNPs nanocomposites ATRIR spectra of vulcanized NREPDM blends and NREPDM
filled functionalized GNPs nanocomposites Raw material characterization: XRD pattern analysis of
commercial Graphene Nanoplatelets KNG -150 K NANO XRD patterns of unfunctionalized GNPs filled NREPDM blends
XRD patterns of functionalized GNPs filled NREPDM blends SEM micrographs of the tensile fracture surfaces of the
vulcanized NREPDM blends of 0 wt GNPs SEM micrographs of the tensile fracture surfaces of the
nanocomposites: abc unfunctionalized GNPs filled NREPDM; def functionalized GNPs filled NREPDM at
500x magnification Free decay curves of GNPs filled NREPDM nanocomposites
containing a vulcanized NREPDM; b 5wt functionalized GNPs; c 1wt unfunctionalized GNPs; d 5wt
unfunctionalized GNPs and e 3wt unfunctionalized GNPs Storage modulus as a function of temperature
Loss modulus as a function of temperature Tan delta as a function of temperature
TEM micrograph of NREPDM nanocomposites a-b 3 wt of unfunctionalized GNPs R5; c-d 5 wt of functionalized
GNPs R2 at different magnification 123
125 127
128 130
131 133
134 136
139 143
144 145
147
xiii
LIST OF ABBREVIATIONS
ANOVA ASTM
BS C
CH CNTs
COOH CV
DSC E
B
ENR ENR-50
EPDM DMTA
e.g ENB
et. at. etc
i.e FTIR
GNPs GO
LGM MAH
Mc MBTS
M
H
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- Analysis of variance
American standard testing method British standard
Carbon Hydrocarbon
Carbon nanotubes Carboxylic group
Conventional vulcanization Differential scanning calorimetry
Elongation at break Epoxidized natural rubber
Natural rubber having 50 of epoxidation Ethylene propylene diene monomer
Dynamic mechanical thermal analysis Example
Ethylidene norbornene and others
Et cetera In example
Fourier transform infrared spectroscopy Graphene nanoplatelets
Graphene oxide Lembaga getah Malaysia
Maleic anhydride Molecular weight between crosslink
2,20-dithiobis benzothiazole Maximum torque
xiv M
L
M
H
-M
L
M
100
M
300
MWNT NR
NVH OH
Phr PNCs
Qm R2
RD RSM
SEM SWNT
Tg Ts
T
2
T
90
Tm TMTD
TEM TOR
UTM Vc
Vr Vs
XRD W
W
1
Wt 6PPD
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- -
- Minimum torque
Torque difference Modulus at 100 elongation
Modulus at 300 elongation Multi-walled carbon nanotube
Natural rubber Noise, vibration and harshness
Hydroxyl group Parts per hundred rubber
Polymer nanocomposites Weight increase of the NREPDM blends in toluene
Constant of determination Research and development
Response surface methodology Scanning electron microscopy
Single-walled carbon nanotube Glass transition temperature
Tensile strength Scorch time
Cure time Melting temperature
Tetramethylthiuram disulfide Transmission electron microscopy
Trans-polyoctenylene rubber Universal testing machine
Crosslink density Volume fraction of the swollen rubber
Molar volume of the solvent toluene X-ray diffraction
Initial mass of samples before the immersion in toluene Mass of samples after the swelling
Weight percent dN-1,3-Dimethylbutyl-N’-phenyl-p phenylenediamine
xv
LIST OF UNITS
o
C ms
min kg
mm μm
s nm
g Hz
- -
- -
- -
- -
- -
- Celsius
Meter per second Percentage
Minute Kilogram
Millimeter Micrometer
Second Nanometer
Gram Hertz
xvi
LIST OF PUBLICATIONS
1. Noraiham Mohamad, Juliana Yaakub, Jeefferie Abd Razak, Mohd Yuhazri Yaakob,