PREPARATION AND DEVELOPMENT OF AN
ETHYLENE VINYL ACETATE (EVA)
COPOLYMER EMULSIFICATION SYSTEM FOR
POUR POINT DEPRESSANT (PPD)
APPLICATION
MUHAMAD RIDHWAN HAFIZ BIN ROSDI
UNIVERSITI SAINS MALAYSIA
2016
PREPARATION AND DEVELOPMENT OF AN ETHYLENE VINYL
ACETATE (EVA) COPOLYMER EMULSIFICATION SYSTEM FOR POUR
POINT DEPRESSANT (PPD) APPLICATION
by
MUHAMAD RIDHWAN HAFIZ BIN ROSDI
Thesis submitted in fulfillment of the requirements
for the degree of
Master of Science
March 2016
ACKNOWLEDGEMENTS
I would like to express my appreciation to my project supervisor, Professor
Azlan Ariffin for taking me as his student, and giving me advices and patient
guidance throughout my Master project. His willingness to give his time so
generously has been very much appreciated.
My grateful thanks are also extended to PhD students, Mr. Mohd Amin Mohd
Razali and Mr. Afrizal Admiral for their commitments as my mentors in giving me a
lot of support, guidance and advice.
Next, I would like to convey my special thanks to Dean, Professor Dr.
Zuhailawati binti Hussain, Deputy Deans, lecturers and all staffs of School Materials
and Mineral Resources Engineering, Universiti Sains Malaysia (USM), for their kind
assistant and supports. Without their kind cooperation, this study would not be
completed on time.
Finally, I wish to thank my parents for their support and encouragement
throughout my study.
ii
TABLE OF CONTENTS
Acknowledgements ii
Table of Contents iii
List of Tables ix
List of Figures xi
List of Plates xvii
List of Abbreviations xviii
List of Symbols xix
Abstrak xx
Abstract
xxii
CHAPTER 1-INTRODUCTION
1.1 Overview
1.2 Problem Statement
1.3 Objectives
1.4 Thesis Structure
1
4
6
6
CHAPTER 2-LITERATURE REVIEW
2.1 Pour Point Depressant (PPD)
2.1.1 Overview
2.1.2 Types of PPD
2.1.2.1 Methacrylate
2.1.2.2 Alkyl acrylate
2.1.3 Pour Point Depressant Mechanism
8
8
9
9
10
12
iii
2.1.4 Subfreezing Applications
2.2 Ethylene Vinyl Acetate (EVA)
2.2.1 Overview of Ethylene Vinyl Acetate (EVA)
2.2.2 Production of EVA
2.2.3 Molecular Structure of EVA
2.2.4 EVA as Pour Point Depressant (PPD)
2.3 Emulsion Characteristic
2.3.1 Overview
2.3.2 Emulsifier Type
2.3.2.1 Ionic
2.3.2.2 Zwitterionic
2.3.2.3 Non-Ionic
2.3.3 Emulsion Stability
2.4 Emulsification Techniques
2.4.1 Overview
2.4.2 Conventional Mechanical Stirrer
2.4.3 High-Shear Mixer
2.4.4 Ultrasonic Devices
2.5 Emulsion Characterization
2.5.1 Freeze-thaw test
2.5.2 Particle size
13
14
14
15
15
17
18
18
21
22
22
22
23
27
27
28
29
30
31
31
32
CHAPTER 3-METHODOLOGY
3.1 Materials
3.2 Experimental Method
33
33
iv
3.2.1 Emulsification of EVA copolymer with different vinyl
acetate (VA) content
3.2.2 Emulsification of EVA copolymer with different Span 80
concentration
3.2.3 Optimization homogenization parameter for EVA
copolymer emulsion
3.2.4 Sample Characterization
3.2.4.1 Fourier Transform Infrared Spectroscopy (FTIR)
3.2.4.2 Gel Permeation Chromatography (GPC)
3.2.4.3 Intrinsic Viscosity
3.2.4.4 Particle Size Measurement
3.2.4.5 Differential Scanning Calorimetry (DSC)
3.2.5 Emulsion Evaluation
3.2.5.1 Interfacial tension measurement
3.2.5.2 Viscometer
3.2.5.3 Freeze-thaw(F/T) stability test
3.2.5.4 Emulsion stability storage
3.2.5.5 Polarized Optical Microscopy
3.2.6 Applied Test
3.2.6.1 Pour point testing (ASTM D97)
3.2.6.2 Pour Point Reduction
33
35
35
38
38
38
38
39
39
39
39
40
41
41
41
42
42
43
CHAPTER 4-RESULTS AND DISCUSSION
4.1 Enhancing Cold Flow-Ability of Ethylene Vinyl Acetate
Copolymer Emulsion: Effect of Vinyl Acetate Content
44
v
4.1.1 Emulsion Formation
4.1.2 Intrinsic Viscosity
4.1.3 Molecular Weight Measurement
4.1.4 Particle Size Measurement
4.1.5 Cold Flowability Of Emulsion Product
4.1.6 Thermal Analysis
4.1.7 Emulsion Stability Study at Room Temperature
4.1.8 Pour Point Measurement
4.1.8.1 Effect of Solvent Ratio
4.1.8.2 Effect of VA Content
4.2 Properties and Stability of EVA Emulsion Copolymer by Non-
Ionic Emulsifier at Different Concentration
4.2.1 Interfacial Tension Evaluation
4.2.2 Particle Size
4.2.3 Viscosity Evaluation
4.2.3.1 Effect of Emulsifier Concentration on Emulsion
Viscosity
4.2.3.2 Effect of Temperature on Emulsion Viscosity
4.2.4 Emulsion Stability
4.2.5 Pour Point Measurement
4.2.5.1 Effect of Emulsifier Concentration on Pour Point
Reduction
4.2.5.2 Effect of PPD Dosage on Pour Point Reduction
4.2.6 Microscopy
4.3 Effect of Homogenization Process Parameters on EVA Emulsion
Properties and Stability
44
46
49
51
53
57
59
61
61
62
64
64
65
67
67
68
70
73
73
74
76
77
vi
4.3.1 Effect of Shearing Intensity
4.3.1.1 Particle Size Generated By Different Shearing
Apparatus
4.3.1.2 Microscopy of Emulsion Generated By Different
Shearing Mixer
4.3.1.3 Freeze-Thaw Stability of Emulsion
4.3.1.4 Viscosity Evaluation of Produced Emulsion at
Different Shearing Intensity
4.3.2 Effect of Homogenization Temperature
4.3.2.1 Particle Size Generated at Different
Homogenization Temperature.
4.3.2.2 Microscopy of EVA Emulsion At Different
Temperature
4.3.2.3 Emulsion Viscosity at Different Homogenization
Temperature
4.3.2.4 Emulsion Storage Stability at Ambient
Temperature
4.3.2.5 Freeze-Thaw Stability of Emulsion
4.3.3 Effect of Homogenization Time
4.3.3.1 Particle Size Generated at Different
Homogenization Time
4.3.3.2 Microscopy of EVA Emulsion at Different
Homogenization Time
4.3.3.3 Emulsion Viscosity at Different Homogenization
Time.
4.3.3.4 Emulsion Storage Stability at Ambient
Temperature
77
77
79
81
84
85
85
87
89
90
91
92
92
93
95
96
vii
4.3.3.5 Freeze-Thaw Stability of Emulsion
97
CHAPTER 5-CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion
5.2 Recommendations
99
101
References 102
Appendices
List of Publication
viii
LIST OF TABLES
Page
Table 3.1 General EVA PPD emulsion formulation. 33
Table 3.2 Formulation for EVA copolymer emulsification
with different VA content
34
Table 3.3 Formulation for EVA 12-S8 emulsification with
different Span 80 loading
35
Table 3.4 Homogenization parameters for EVA 12-S8-E3
emulsification with different shearing speed
36
Table 3.5 Homogenization parameters for EVA 12-S8-E3
emulsification with different emulsification
temperature
36
Table 3.6 Homogenization parameters for EVA 12-S8-E3
emulsification with different emulsification
temperature
37
Table 4.1 Overview of emulsion formation for EVA12 and
EVA18.
45
Table 4.2 Effect of VA content in EVA copolymer in
emulsion formation.
49
Table 4.3 Emulsion stability duration for samples EVA12 and
EVA18
60
Table A-1 Pour point test data for EVA 12 at different
solvent/polymer ratio
ix
Table A-2 Pour point test data for EVA 18 at different
solvent/polymer ratio
Table A-3 Pour point test data for EVA PPD at different
emulsifier concentrations.
x
LIST OF FIGURES
Page
Figure 1.1 Paraffin wax deposition at pipelines (Guozhong
and Gang, 2010)
1
Figure 2.1 Unit group of Polymethacrylates (El-Gamal et al.,
1997)
10
Figure 2.2 Unit group of Polyacrylates (El-Gamal et al.,
1997)
11
Figure 2.3 PPD Inhibition mechanism of wax modification.
2A) Chemical structure of wax. 2B) Crystal
structure of wax. 2C) Crystal structure of growing
wax lattice. 2D) Polymeric additive with wax-like
components. 2E) Co-crystallization of wax and
PPD. 2F) Sterically hindered wax structure (Wang
et al., 1999).
12
Figure 2.4 Traditional solvent-based paraffin inhibitor
polymers solidified at 0oC
13
Figure 2.5 EVA chemical structure (Soni and Bharambe,
2008)
16
Figure 2.6 PPD comb polymer diagram (Atta, 1997) 18
Figure 2.7 Various extrinsic parameters that can negatively
impact the stability of emulsions.(Weiss, 2002)
24
Figure 2.8 Destabilization paths of emulsions(Wegmann,
1997)
26
xi
Figure 2.9 2-step of homogenization process.(Degner et al.,
2014)
27
Figure 2.10 Mechanical Stirrer (paddle impeller) flow
pattern(Hemrajani and Tatterson, 2004)
29
Figure 2.11 High shear mixer flow pattern (Charles Ross &
Son Company)
29
Figure 3.1 Overall experimental design flowchart of EVA
emulsification process.
37
Figure 4.1 Emulsion flowability evaluation based on
viscosity at 25 oC
44
Figure 4.2 Reduced viscosities of EVA copolymers with
different vinyl acetate contents
47
Figure 4.3 Intrinsic viscosities of EVA copolymers with
different vinyl acetate contents
48
Figure 4.4 Molecular weight of EVA copolymers 50
Figure 4.5 Particle size distribution curve EVA12 52
Figure 4.6 Particle size distribution curve EVA18 52
Figure 4.7 Viscosity evaluation at different temperature for
EVA 12
55
Figure 4.8 Viscosity evaluation at different temperature for
EVA 18
55
xii
Figure 4.9 Viscosity evaluation at different temperature for
EVA 25
56
Figure 4.10 Viscosity evaluation at different temperature for
EVA 40
56
Figure 4.11 DSC thermogram of EVA 12S8 before and after
emulsification
58
Figure 4.12 DSC thermogram of EVA 18S8 before and after
emulsification
59
Figure 4.13 Pour point reductions of (a) EVA 12 and (b) EVA
18 with different solvent percentages at various
dosages.
61
Figure 4.14 Pour point reduction of paraffin wax after addition
EVA12 and EVA18 at 8:1 solvent/polymer ratio at
various dosages.
63
Figure 4.15 The interfacial tension as a function of emulsifier
concentration for EVA12S8
65
Figure 4.16 Particle size values at different emulsifier
concentrations for EVA12S8
66
Figure 4.17 Emulsifier concentration (%) versus emulsion
viscosity at ambient temperature for EVA12S8
68
Figure 4.18 Effect of temperature on the emulsion viscosity
for each emulsifier percentage concentration for
EVA12S8
69
xiii
Figure 4.19 Emulsion destabilization time versus emulsifier
concentration at ambient temperature for
EVA12S8
70
Figure 4.20 Particle size changes during freeze thaw cycle for
EVA12S8 at different emulsifier loading
72
Figure 4.21 Effect of emulsifier concentration (%) on pour
point reduction at 300 ppm for EVA12S8
73
Figure 4.22 Effect of emulsifier concentration toward pour
point reduction of EVA12S8
75
Figure 4.23 Morphology of paraffin wax crystals before
treated with EVA12S8E3
76
Figure 4.24 Morphology of paraffin wax crystals after treated
with EVA12S8E3 emulsion (at 3 % of
concentration at 300 ppm - X10 magnification)
77
Figure 4.25 Effect of shearing intensity on the particle size of
the EVA12S8E3 emulsion
79
Figure 4.26 Microscopic picture (magnification 10×) of the
paddle-agitated EVA12S8E3 emulsion
80
Figure 4.27 Microscopic picture (magnification 10×) of the
high-shear EVA12S8E3 emulsion
80
Figure 4.28 Sedimentation behaviour progression of the HS1
emulsion at different F/T cycle.
82
xiv
Figure 4.29 Sedimented aqueous phase in the EVA12S8E3
emulsion as a function of the F/T cycle at different
shearing intensity.
83
Figure 4.30 Emulsion particle coalescence behavior during
F/T cycle test.
84
Figure 4.31 Effect of shearing intensity on the viscosity of the
EVA12S8E3 emulsion at ambient temperature
85
Figure 4.32 Effect of homogenization temperature on
EVA12S8E3 emulsion particle size
86
Figure 4.33 Micrograph of emulsion at different
homogenization termperature
88
Figure 4.34 Effect of different homogenization temperature on
EVA12S8E3 emulsions viscosity
89
Figure 4.35 Effect of homogenization temperature on
EVA12S8E3 emulsions stability on ambient
temperature
90
Figure 4.36 Sedimented aqueous phase in the EVA12S8E3
emulsion as function of F/T cycle at different
homogenization temperature
91
Figure 4.37 Effect of homogenization time on EVA12S8E3
emulsion particle size
93
Figure 4.38 Micrograph of emulsions at different
homogenization time
95
xv
Figure 4.39 Effect of different homogenization time on
EVA12S8E3 emulsions viscosity
96
Figure 4.40 Effect og homogenization time on EVA12S8E3
emulsions stability at ambient temperature
97
Figure 4.41 Sedimented aqueos phase in the EVA12S8E3
emulsions as a function of the F/T cycle at
different homogenization time.
98
xvi
LIST OF PLATES
Page
Plate 3.1 Brookfield viscometer 40
Plate 3.2 Pour point Tester Apparatus 42
xvii
LIST OF ABBREVIATIONS
EVA Ethylene Vinyl Acetate
PPD Pour Point Depressant
rpm Rotation per minute
FTIR Fourier Transfer Infra Red
DSC Differential Scanning Calorimetry
ppm Part per million
F/T Freeze-thaw
Mw Molecular Weight
xviii
LIST OF SYMBOLS
dL/g Deci litre/gram
g gram
µm Micrometer
oC degree celcius
mN/m Milinewton/meter
g/mol Gram per mol
% Percentage
Δ Delta
mPa.s Millipascal-second
oC Degree celcius
xix
PENYEDIAAN DAN PEMBANGUNAN SISTEM PENGEMULSIAN
ETILENEA VINIL ASETAT (EVA) KOPOLIMER DALAM APLIKASI
AGEN PENEKAN TITIK TUANG
ABSTRAK
Produk emulsi agen penekan titik tuang berkelebihan untuk digunakan dalam suhu
yang rendah kerana ia meningkatkan ciri-ciri pengendalian fizikal berbanding produk
tradisional. Penyediaan emulsi EVA kopolimer yang stabil adalah kritikal bagi
kejayaan penghasilan emulsi EVA kopolimer. Kajian ini mempertimbangkan kesan
VA (vinil asetat) yang berbeza untuk EVA kopolimer dalam menghasilkan emulsi
untuk mengekalkan kestabilan emulsi. Melalui analisa kelikatan intrinsik dan
kromatografi penyerapan gel, hubungan antara kandungan VA daripada EVA
kopolimer dan tindak balas keupayaan mengalir emulsi semasa pengemulsian telah
diterokai. Keputusan menunjukkan bahawa kandungan VA yang tinggi menyumbang
kepada ketidakstabilan emulsi. Kesan kandungan VA dikaji secara lanjut dengan
mengubah nisbah pelarut / polimer untuk memerhati tindak balas keupayaan
mengalir emulsi. Hasil kajian menunjukkan bahawa dalam setiap siri, nisbah pelarut /
polimer yang tinggi menghasilkan keupayaan aliran emulsi yang baik pada
kandungan VA, 12% dan 18 %. Tambahan pula, keputusan menunjukkan bahawa
parameter keterlarutan dan kandungan VA menunjukkan korelasi yang baik dan
berat molekul mempunyai pengaruh penting ke atas tindak balas keupayaan mengalir
emulsi dan pengurangan titik tuang. Emulsi EVA12S8 menunjukkan prestasi
pengurangan titik tuang yang terbaik, 12oC pada 300 ppm. Selepas itu, kesan agen
emulsi tidak berion terhadap kestabilan emulsi dikaji untuk memperolehi muatan
yang optimum. Alat interfacial tensionmeter, alat ZetaSizer Malvern, ujian
kestabilan emulsi, kaedah kitaran beku-cair, dan Brookfield meter telah digunakan
xx
untuk menyiasat kestabilan emulsi. Peningkatan kepekatan agen emulsi sehingga 3 %
mengurangkan ketegangan antara muka dalam sistem cekap, dengan itu
membolehkan pemecahan titisan yang lebih efisien semasa pengemulsian. Ini
mengurangkan saiz titisan dimana akan meningkatkan kestabilan dan kelikatan
system. Melebihi kandungan ini, kestabilan emulsi mula merosot. Selepas itu, kesan
pemboleh ubah proses penyeragaman yang berbeza terhadap kestabilan emulsi telah
dikaji berdasarkan uji kaji eksperimen. Emulsi ini telah disediakan menggunakan
pengacau mekanikal dan pengadun ricih tinggi. Sorbitan monooleate (Span 80)
ditetapkan pada kandungan 3% sebagai ejen emulsi. Pembolehubah yang dikaji
adalah kekuatan pengacau, suhu process penyeragaman dan masa. Hasil kajian
menunjukan bahawa kondisi optimum bagi process penyeragaman adalah 5000 rpm
bagi kekuatan pengacau, 80oC untuk suhu process penyeragaman dan 30 minit untuk
masa. Melampaui kondisi tersebut yang biasanya dirujuk pemprosesan yang terlebih
batas, ia akan menjejaskan saiz zarah emulsi dan kestabilan emulsi.
xxi
PREPARATION AND DEVELOPMENT OF AN ETHYLENE VINYL
ACETATE (EVA) COPOLYMER EMULSIFICATION SYSTEM FOR
POUR POINT DEPRESSANT (PPD) APPLICATION
ABSTRACT
PPD emulsion product is advantageous for use in sub-ambient temperature as it
improve the physical handling characteristic compared to traditional product. The
preparation of stable EVA copolymer emulsion is critical for the success of
production of EVA copolymer emulsion. This study considers the effect of different
VA (vinyl acetate) of EVA copolymer in producing the emulsion form as to maintain
the emulsion stability. Through the intrinsic viscosity and gel permeation
chromatography analysis, the relationship between VA content of EVA copolymer
and the flow ability response of an emulsion during emulsification is explored. The
result is shown that higher VA content contributes to the instability of the emulsion.
Effects VA content were further study by varying the solvent/polymer ratio to
observe the flow-response of the emulsion. The results showed that in each series, a
higher solvent/polymer ratio produces good flow ability emulsion at 12% and 18% of
VA content. Furthermore, these results also revealed that the solubility parameter
and VA content show good correlation and that molecular weight has an important
influence on the flow ability response of emulsion and pour point reduction.
EVA12S8 emulsion exhibited the highest pour point reduction, 12oC at 300 ppm.
Subsequently, impact of nonionic emulsifier on emulsion stability was studied as to
obtain the optimal loading. Interfacial tensiometer, ZetaSizer Malvern instrument,
emulsion stability test, freeze–thaw cycle method, and Brookfield viscometer were
employed to investigate emulsion stability. Increasing the emulsifier concentration
xxii
up to 3% will decrease the interfacial tension in the system efficiently, thus allowing
for more efficient droplet break-up during emulsification. This will reduce the
particle size, which in turn increased the stability and viscosity of the system.
Beyond this loading, the emulsion stability began to decline. Afterward, the effects
of different homogenization parameters on emulsion stability were investigated. The
emulsion was prepared using paddle agitator and high-shear mixer. Sorbitan
monooleate(Span 80) at constant 3% loading as emulsifier. Three parameters were
monitored in this section, namely stirring intensity, homogenization temperature and
time. The results showed that the optimum homogenization conditions are: stirring
intensity, 5000 rpm; homogenization temperature, 80oC and homogenization time, 30
minutes. Exceed these conditions as commonly referred as over-processing; it will
impair the emulsion particle size and the emulsion stability.
xxiii
Recommended
