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The dispersed phase in a binary polymer blend can take the form of fibers, lamella and A-B-A droplet-in-droplet type structures(Molau & Keskkula, 1966; Reignier & Favis, 2000). In an A/B binary blend, the dispersed phase type structure(Figure 6-1b) is converted to a continuous type structure through an increase in the composition. By increasing the concentration of dispersed phase A, droplets coalesce resulting in a percolation threshold point being reached. This percolation threshold is the first connected pathway in the blend(Figure 6-1a). Classic percolation theory defines the percolation threshold as the onset of long-range connectivity in random systems and it occurs at a volume fraction of 0.156 for a random mono-disperse distribution of spheres(Scher & Zallen, 1970). Through a further increase of minor phase concentration, levels of continuity increase until a fully-interconnected co-continuous morphology is obtained(Figure 6-1c). Co-continuity is defined as the case where each phase is fully continuous in the blend system. Since this often occurs over a concentration range for binary polymer blends, this is also known as the region of dual-phase continuity. Phase inversion is defined as the concentration point where co-continuity converts into a matrix/dispersed phase morphology. It has been reported that the interfacial tension and the viscosity ratio can also influence the position of the region of dual-phase continuity(Jordhamo, et al., 1986; Mekhilef & Verhoogt, 1996). Much less work has been carried out on the fundamental morphological states present in ternary polymer blends comprised of significant quantities of 3 distinct phases. Recently, some papers have described the morphological behavior of ternary systems with complex morphologies such as A-B-C composite-droplet structures(Reignier & Favis, 2000; Reignier, et al., 2003) and double-percolated morphology(Zhang, et al., 2007). Complete wetting and partial wetting are two broad categories of morphological states possible for ternary polymer blends. In an A/B/C system, complete wetting describes the case where the most stable thermodynamic state is when one of the phases, say phase B, will always position itself to completely separate phases A and C. In that case phases A and B completely wet each other and phases B and C also completely wet each other. In the case of partial wetting, the most stable thermodynamic state is when there is three-phase contact. In that case, for example, droplets of B will situate at the A/C interface such that all three phases are in contact with each other(Torza & Mason, 1970; Virgilio, Marc-Aurele, et al., 2009). Both complete and partial wetting can be described by spreading theory as defined by Harkins equation. A 174
modified version of Harkins theory(Harkins & Feldman, 1922) was first reported by Torza et al.(Torza & Mason, 1970). Hobbs et al.(Hobbs, et al., 1988) followed and developed a modified Harkins equation and calculated three spreading coefficients of ternary polymer systems to predict the possible morphological structures as shown in Equation 6-1 : λ = γ − γ − γ Equation 6-1 ij jk ik ij where λij is defined as the spreading coefficient defining the tendency of component (i) to encapsulate or spread onto component (j) in the matrix of component (k). The interfacial tensions of the various polymer pairs are represented as γij, γik and γjk. In a certain ternary blend, 3 different spreading coefficients exist including λij = λik, λji = λjk, and λki = λkj.A positive value of one of the spreading coefficients indicates that the ternary blend will demonstrate complete wetting behavior as shown in Figure 6-2a. For example, a positive value of λik demonstrates that phase (i) spreads over phase (k) leading to a separation of phases (j) and (k) by phase (i) at the interface. A matrix/core-shell dispersed phase structure is an example of complete wetting in which phase B, for example, encapsulates dispersed phase C in a matrix of A. On the other hand, negative values for all three spreading coefficients indicates a partial wetting behavior in which all components have an interface with each other, or all three meet along a common line of three phase contact (Figure 6-2a)(Virgilio, Marc-Aurele, et al., 2009). A number of complex morphologies in ternary HDPE/PS/PMMA blends have been investigated. Reignier et al.(Reignier & Favis, 2000) examined the core-shell morphology of PMMA encapsulated by PS in an HDPE matrix in detail. Zhang et al.(Zhang, et al., 2007) reported on the generation of a double-percolated structure comprised of a PS layer at the HDPE/PMMA interface through the control of the composition of the components. Virgilio et al.(Virgilio, Marc-Aurele, et al., 2009) reported the case of partial wetting for a HDPE/PS/PP blend demonstrating a close-packed droplet array of PS at the interface of HDPE and PP. Guo et al.(Guo, Gvozdic, et al., 1997; Guo, Packirisamy, et al., 1997), studied the morphology of ternary and quaternary blends and proposed a model which includes not only the interfacial tension, but also the interfacial area of the phases. To date, however, the detailed examination of all the possible morphological states over the entire composition range for a ternary polymer blend has not been carried out. 175
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© Sepehr Ravati, 2010. UNIVERSITÉ
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DEDICATED To my parents iii
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RÉSUMÉ Cette thèse présente, po
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devenir une structure hiérarchique
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ABSTRACT This thesis presents, for
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system can be increased from 10 -15
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CONDENSÉ EN FRANÇAIS Dans ce trav
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deuxième coquille de PS. Les phase
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structures à percolation multiple
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autre sous-type de morphologie dans
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TABLE OF CONTENTS DEDICATION.......
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xxiii 2.4.1.1.1 Charged Polymer Ads
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5.3.4 Annealing Test ..............
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xxvii REFERENCES ..................
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LIST OF FIGURES xxix Figure 1-1. a)
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Figure 2-12. SEM photomicrograph of
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Figure 2-34. Schematic view of diff
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Figure 4-8. SEM micrographs of vari
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Figure 5-6. a),b) Scanning electron
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and c) triangular concentration dia
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n number of moles p concentration o
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AFM atomic force microscopy LIST OF
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PS-co-PMMA copolymer of PS and PMMA
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1.1 Introduction CHAPTER 1 - INTROD
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Figure 1-2. Human heart, longitudin
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One of the applications for porous
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On the other hand, a novel tri-cont
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2.1 Polymer Blends CHAPTER 2 - LITE
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Based on Sterling’s approximation
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Antonoff’s rule (Equation 2-13) i
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2.1.2.1 Binary Polymer Blends 2.1.2
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Some other studies(Everaert, Aerts,
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where the parameter z is dependent
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“compatibilization” was suggest
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a) λ BC A and B are matrices, b) C
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Reignier & Favis, 2000, 2003a; Reig
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measure the interfacial tension of
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a) b) Figure 2-6. Dependence of the
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Omonov et al. found double percolat
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2.1.2.2.3 Effect of Composition on
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a) b) C B A c) Figure 2-12. SEM pho
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In the case where PS is the matrix,
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Posthuma de Boer, 1999) (Kumin & Ch
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lattice, such as square lattice, wi
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magnetization, which is a function
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Polymers have long been thought of
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epoxy as a function of nanotube wei
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Figure 2-19. Approaching the percol
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Figure 2-21. Transmission electron
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Figure 2-22: Dependence of PE conti
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Figure 2-24. Plot of the total numb
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chain provides the conductive path
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2.3.1.2.1 Polyaniline One of the mo
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CoPA/LLDPE/PANI blend and a poor-qu
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Narkis and co-workers extended and
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Figure 2-31: Conductivity of PVDF/P
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organic thin films, a novel and str
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on the topic have been reported in
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succeeded in creating thin films wi
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Addition of salt to the solution of
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different from that of linear homop
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Figure 2-39. Macromolecule with a)
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polyanion such as hyaluronan (HA)(P
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2.4.1.1.7 Effect of Salt on Multila
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2.4.1.1.8 Overcompensation of the M
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important factors determining the g
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As shown in Figure 2-44, swelling a
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increasing the pH value due to a de
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CHAPTER 3 - ORGANIZATION OF THE ART
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discussed above, HDPE, PS, PMMA, an
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CHAPTER 4 - LOW PERCOLATION THRESHO
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or model which predicts where the p
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concentration threshold for the ons
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chemical and weathering resistance,
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Table 4-1. Material Characteristics
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filled with blend pellets. To facil
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4.3.6 Conductivity Measurements DC
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experimentally in this research gro
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a) b) c) d) Figure 4-4. Schematic i
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microstructure of the quaternary bl
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a) b) c) d) Figure 4-6. SEM microgr
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a) b) PVDF PS PMMA c) d) e) HDPE PS
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Uniform layers of PS and PMMA situa
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the concentration of HDPE is increa
Page 169 and 170: a) b) c) e) Figure 4-11. SEM microg
Page 171 and 172: melt-processable and contains 25 wt
Page 173 and 174: One question that should be address
Page 175 and 176: Conductivity(S/cm) Ternary Blend 1,
Page 177 and 178: phase(PMMA), the concentration of P
Page 179 and 180: (6) Virgilio, N.; Desjardins, P.; L
Page 181 and 182: ONION MORPHOLOGY HDPE PVDF PS Contr
Page 183 and 184: work described above has focused on
Page 185 and 186: thermodynamic explanation to predic
Page 187 and 188: four-point probe increases continuo
Page 189 and 190: in the rheology tests were compress
Page 191 and 192: 5.3.6 Layer-by-Layer Deposition The
Page 193 and 194: prepare a polymer blend structure w
Page 195 and 196: a) b) c) Figure 5-3. Scanning elect
Page 197 and 198: spontaneously self-assembled. After
Page 199 and 200: a) b) c) d) e) f) g) h) Figure 5-5.
Page 201 and 202: Since the ultra-low surface area va
Page 203 and 204: c) a) b) Figure 5-6. a),b) Scanning
Page 205 and 206: salt to a PSS polyelectrolyte solut
Page 207 and 208: A relationship between macropore si
Page 209 and 210: close together. It is interesting t
Page 211 and 212: Figure 5-9. Mass increase (%) indic
Page 213 and 214: In this work the conductance of the
Page 215 and 216: deposited PANI layers increases unt
Page 217 and 218: (52) Guo, H. F.; Packirisamy, S.; G
Page 219: 6.2 Introduction It is well-known t
Page 223 and 224: 6.3 Experimental 6.3.1 Materials Co
Page 225 and 226: Complex voscosity (Pa.s) 1,0E+04 1,
Page 227 and 228: 6.3.5.2 Focused Ion Beam (FIB) and
Page 229 and 230: a) c) b) d) e) f) PMMA PMMA HDPE HD
Page 231 and 232: y Harkins theory, PS will always si
Page 233 and 234: a) b) c) d) e) f) PS Figure 6-6. a)
Page 235 and 236: a) b) HDPE : black PS : grey PMMA :
Page 237 and 238: 6.4.6 Continuity, Co-continuity, an
Page 239 and 240: c) V III II I VII I IV VI Figure 6-
Page 241 and 242: Continuity Scheme (a) Figure 6-10.
Page 243 and 244: Addition of a low concentration of
Page 245 and 246: Addition of small amounts of HDPE t
Page 247 and 248: icontinuous network with the HDPE.
Page 249 and 250: Three examples are shown in Figure
Page 251 and 252: (9) Mekhilef, N.; Verhoogt, H. Poly
Page 253 and 254: structures are formed due to the co
Page 255 and 256: CONCLUSION AND RECOMMENDATIONS In t
Page 257 and 258: REFERENCES A. K. Gupta, K. R. S. (1
Page 259 and 260: Caruso, F. (2003). Hollow Inorganic
Page 261 and 262: Domenech, S. C., Bortoluzzi, J. H.,
Page 263 and 264: Geuskens, G., Gielens, J. L., Geshe
Page 265 and 266: Hou, S., Harrell, C. C., Trofin, L.
Page 267 and 268: Krass, H., Papastavrou, G., & Kurth
Page 269 and 270: Macdiarmid, A. G., Jin-Chih, C., Ha
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Niziol, J., & Laska, J. (1999). Con
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Reghu, M., Yoon, C. O., Yang, C. Y.
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Shirakawa, H., Louis, E. L., MacDia
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Utracki, L. A. (1991). On the visco
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Yasuda, K., Armstrong, R., & Cohen,
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literature has examined factors inf
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(Reignier & Favis, 2000, 2003a; Rei
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Table A-1.2. Interfacial tensions a
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acquisition of images with a very h
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Table A-1.3. Continuity of the PMMA
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(17) Reignier, J.; Favis, B. D., Ma
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PANI. Theoretically, the extent of
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Equation A-2.7 0( ) 0 1. 5 σ = σ
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Cumulative Mass × 10 5 (g) dipping
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of PANI, and an increase in the con
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Resistance(ohm) 1.0E+12 1.0E+11 1.0
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esistance value. Samples containing
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The results of resistance for PS/PE
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Caruso, F., & Schuler, C. (2000). E
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