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Hai Wang - One of the best experts on this subject based on the ideXlab platform.
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formation of nascent soot and other condensed phase materials in flames
Proceedings of the Combustion Institute, 2011Co-Authors: Hai WangAbstract:Abstract Over the last two decades, our understanding of soot formation has evolved from an empirical, phenomenological description to an age of quantitative modeling for at least small fuel compounds. In this paper, we review the current state of knowledge of the fundamental sooting processes, including the chemistry of soot precursors, Particle Nucleation and mass/size growth. The discussion shows that though much progress has been made, critical gaps remain in many areas of our knowledge. We propose the roles of certain aromatic radicals resulting from localized π electron structures in Particle Nucleation and subsequent mass growth. The existence of these free radicals provides a rational explanation for the strong binding forces needed for forming initial clusters of polycyclic aromatic hydrocarbons. They may also explain a range of currently unexplained sooting phenomena, including the large amount of aliphatics observed in nascent soot formed in laminar premixed flames and the mass growth of soot in the absence of gas-phase H atoms. While the above suggestions are inspired, to an extent, by recent theoretical findings from the materials research community, this paper also demonstrates that the knowledge garnered through our longstanding interest in soot formation may well be carried over to flame synthesis of functional nanomaterials for clean and renewable energy applications. In particular, work on flame-synthesized thin films of nanocrystalline titania illustrates how our combustion knowledge might be useful for developing advanced yet inexpensive thin-film solar cells and chemical sensors for detecting gaseous air pollutants.
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Particle size distribution function of incipient soot in laminar premixed ethylene flames effect of flame temperature
Proceedings of the Combustion Institute, 2005Co-Authors: Bin Zhao, Zhiwei Yang, Murray V Johnston, Hai WangAbstract:Abstract Particle size distribution functions (PSDFs) of incipient soot formed in laminar premixed 24.2% ethylene–37.9% oxygen-diluent (nitrogen and/or argon) flames with an equivalence ratio of 1.92 were studied by online sampling and scanning mobility Particle sizer. Two series of flames were studied to quantify the effect of flame temperature on the characteristics of PSDFs. In the first series, the variation of the flame temperature was accomplished by varying the cold gas velocity. Temperature in the second series of flames was manipulated by the diluent composition from argon to nitrogen. The results show that for flames with the maximum temperature ( T max ) around 1800 K the soot PSDFs were distinctively bimodal. As the flame temperature was increased to ∼1850 K, bimodality faded away. The distribution was unimodal for T max > 1900 K. The variation of the characteristics of the PSDF as a function of the flame temperature is consistent with the theoretical explanation that bimodality is the result of competition between persistent Particle Nucleation and Particle–Particle coagulation in low-temperature flames.
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measurement and numerical simulation of soot Particle size distribution functions in a laminar premixed ethylene oxygen argon flame
Combustion and Flame, 2003Co-Authors: Bin Zhao, Hai Wang, Zhiwei Yang, Murray V Johnston, Anthony S Wexler, Michael Balthasar, Markus KraftAbstract:Abstract Spatially resolved measurement of the soot Particle size distribution function (PSDF) was made in a laminar premixed ethylene-argon-oxygen flame (φ = 2.07) using a scanning mobility Particle sizer. The emphasis of the study was to follow the evolution of the PSDF from the onset of Particle inception to Particle mass growth. At the onset of soot inception, the PSDF was found to follow a power-law dependence on Particle diameter. The PSDF becomes bimodal at larger height above the burner surface, and remains bimodal throughout the flame. Numerical simulation using a kinetic model proposed previously and a stochastic approach to solve aerosol dynamics equations again showed a bimodal PSDF. Further analysis revealed that bimodality is intrinsic to an aerosol process involving Particle-Particle coagulation and Particle Nucleation dominated by monomer dimerization.
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detailed modeling of soot formation in laminar premixed ethylene flames at a pressure of 10 bar
Combustion and Flame, 1995Co-Authors: Andrei Kazakov, Hai Wang, Michael FrenklachAbstract:Abstract Detailed modeling of soot Particle Nucleation, growth and oxidation in laminar premixed ethylene-air flames at a pressure of 10 bar is presented. The employed kinetic model of soot formation, developed and tested earlier for subatmospheric and atmospheric flames, can quantitatively describe the experimental soot volume fraction profiles collected in a number of ehtylene flames at high pressures. The kinetic model consists of initial aromatic ring formation from nonaromatic species, planar polycyclic aromatic hydrocarbon (PAH) growth through the hydrogen-abstraction-acetylene-addition reaction mechanism, Particle Nucleation through coalescence of PAHs, Particle growth by coagulation and surface reactions of the forming clusters and Particles, and Particle oxidation. Analysis of the computational results obtained at 10 bar and additional tests performed for a 1-bar flame suggest that the influence of pressure on soot production arises mainly from the larger concentration of acetylene, which affects both the soot surface growth and the Nucleation of soot Particles.
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detailed modeling of soot Particle Nucleation and growth
Symposium (International) on Combustion, 1991Co-Authors: Michael Frenklach, Hai WangAbstract:Detailed modeling of soot Particle Nucleation and growth in laminar premixed hydrocarbon flames is presented. The model begins with fuel pyrolysis, followed by the formation of polycyclic aromatic hydrocarbons, their planar growth and coagulation into spherical Particles, and finally, surface growth and oxidation of the Particles. The computational results are in quantitative agreement with experimental results from several laminar premixed hydrocarbon flames. A detailed analysis of soot Particle inception and surface growth processes is presented. Surface growth was described in terms of elementary chemical reactions of surface active sites. The density of these sites was found to depend on the chemical environment. The model predicts the classical picture of soot Particle inception and the classical description of soot Particle structure.
Steven L. Girshick - One of the best experts on this subject based on the ideXlab platform.
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Particle Nucleation and growth in dusty plasmas on the importance of charged neutral interactions
Journal of Vacuum Science and Technology, 2020Co-Authors: Steven L. GirshickAbstract:Particle Nucleation and growth in gases involves Nucleation via growth of small molecular or ionic clusters, growth by vapor deposition on nanoParticle surfaces, and coagulation due to collisions between nanoParticles. Under typical conditions that apply in low-pressure nonthermal plasmas, all three of these phenomena are dominated by interactions between negatively charged bodies (anion clusters or nanoParticles) and neutral ones (molecules or nanoParticles), with collision rates enhanced by the dipole or image potential induced in the neutral collision partner. The current understanding of these phenomena is reviewed, with a focus on silane-containing plasmas in which silicon nanoParticles nucleate and grow.Particle Nucleation and growth in gases involves Nucleation via growth of small molecular or ionic clusters, growth by vapor deposition on nanoParticle surfaces, and coagulation due to collisions between nanoParticles. Under typical conditions that apply in low-pressure nonthermal plasmas, all three of these phenomena are dominated by interactions between negatively charged bodies (anion clusters or nanoParticles) and neutral ones (molecules or nanoParticles), with collision rates enhanced by the dipole or image potential induced in the neutral collision partner. The current understanding of these phenomena is reviewed, with a focus on silane-containing plasmas in which silicon nanoParticles nucleate and grow.
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Numerical modeling of an RF argon-silane plasma with dust Particle Nucleation and growth
Plasma Chemistry and Plasma Processing, 2014Co-Authors: Pulkit Agarwal, Steven L. GirshickAbstract:A one-dimensional numerical model and simulation results are presented for a capacitively-coupled radio frequency parallel-plate argon–silane dusty plasma. The model includes self-consistently coupled numerical modules, including a plasma fluid model, a sectional aerosol model, and a simple chemistry model to predict rates of Particle Nucleation and surface growth. Operating conditions considered include 13.56 MHz frequency, 100 mTorr pressure, a 4-cm electrode gap, gas flow through the top electrode with a 30:1 ratio of argon to silane, and applied radio frequency voltage amplitude of either 100 or 250 V. In the higher voltage case two lobes of relatively large Particles are formed by ion drag, while fresh Nucleation occurs in the void between these lobes. It is shown that the reason that fresh Nucleation occurs in the void involves an interplay among several coupled phenomena, including nanoParticle transport, the plasma potential profile, and trapping of silicon hydride anions that drive Nucleation in this system.
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An experimental and numerical study of Particle Nucleation and growth during low-pressure thermal decomposition of silane
Journal of Aerosol Science, 2003Co-Authors: Sandeep Nijhawan, S M Suh, Mark T. Swihart, Steven L. Girshick, Peter H. Mcmurry, S. A. Campbell, John E BrockmannAbstract:This paper discusses an experimental and numerical study of the Nucleation and growth of Particles during low-pressure (similar to1.0 Torr) thermal decomposition of silane (SiH4). A Particle Beam Mass Spectrometer was used to measure Particle size distributions in a parallel-plate showerhead-type semiconductor reactor. An aerosol dynamics moment-type formulation coupled with a chemically reacting fluid flow model was used to predict Particle concentration, size, and transport in the reactor. Particle Nucleation kinetics via a sequence of chemical clustering reactions among silicon hydride molecular clusters, growth by heterogeneous chemical reactions on Particle surfaces and coagulation, and transport by convection, diffusion, and thermophoresis were included in the model. The effect of pressure, temperature, flow residence time, carrier gas, and silane concentration were examined under conditions typically used for low-pressure (similar to1 Torr) thermal chemical vapor deposition of polysilicon. The numerical simulations predict that several pathways involving linear and polycyclic silicon hydride molecules result in formation of Particle "nuclei," which subsequently grow by heterogeneous reactions on the Particle surfaces. The model is in good agreement with observations for the pressure and temperature at which Particle formation begins, Particle sizes and growth rates, and relative Particle concentrations at various process conditions. A simplified, computationally inexpensive, quasi-coupled modeling approach is suggested as an engineering tool for process equipment design and contamination control during low-pressure thermal silicon deposition. (C) 2003 Elsevier Science Ltd. All rights reserved.
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Numerical study of the effect of gas temperature on the time for onset of Particle Nucleation in argon-silane low-pressure plasmas
Journal of Physics D: Applied Physics, 2003Co-Authors: Upendra Bhandarkar, Uwe Kortshagen, Steven L. GirshickAbstract:Particle Nucleation in silane plasmas has attracted interest for the past decade, both due to the basic problems of plasma chemistry involved and the importance of silane plasmas for many applications. A better understanding of Particle Nucleation may facilitate the avoidance of undesirable Particle contamination as well as enable the controlled production of nanoParticles for novel applications. While understanding of Particle Nucleation has significantly advanced over the past years, a number of questions have not been resolved. Among these is the delay of Particle Nucleation with an increasing gas temperature, which has been observed in experiments in argon-silane plasmas. We have developed a quasi-one-dimensional model to simulate Particle Nucleation and growth in silane containing plasmas. In this paper we present a comparative study of the various effects that have been proposed as explanations for the Nucleation delay. Our results suggest that the temperature dependence of the Brownian diffusion coefficient is the most important effect, as diffusion affects both the loss rate and growth rate of Particles.
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thermochemistry and kinetics of silicon hydride cluster formation during thermal decomposition of silane
Journal of Physical Chemistry B, 1999Co-Authors: Mark T. Swihart, Steven L. GirshickAbstract:Product contamination by Particles nucleated within the processing environment often limits the deposition rate during chemical vapor deposition processes. A fundamental understanding of how these Particles nucleate could allow higher growth rates while minimizing Particle contamination. Here we present an extensive chemical kinetic mechanism for silicon hydride cluster formation during silane pyrolysis. This mechanism includes detailed chemical information about the relative stability and reactivity of different possible silicon hydride clusters. It provides a means of calculating a Particle Nucleation rate that can be used as the Nucleation source term in aerosol dynamics models that predict Particle formation, growth, and transport. A group additivity method was developed to estimate thermochemical properties of the silicon hydride clusters. Reactivity rules for the silicon hydride clusters were proposed based on the group additivity estimates for the reaction thermochemistry and the analogous reaction...
Michael Frenklach - One of the best experts on this subject based on the ideXlab platform.
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monte carlo simulation of soot Particle coagulation and aggregation the effect of a realistic size distribution
Proceedings of the Combustion Institute, 2005Co-Authors: Michael Balthasar, Michael FrenklachAbstract:Abstract The evolution of the morphology of primary soot Particles was investigated in a laminar premixed flame with the emphasis on the effect of a realistic Particle size distribution. A time-dependent Monte-Carlo method was used to calculate flame trajectories of single Particles. In the Nucleation zone of the flame, Particles were grown by coagulation and simultaneous surface growth. The Particles for coagulation were selected according to a pre-calculated size distribution obtained by solving the dynamics of the entire soot Particle ensemble. In the post-Nucleation zone, defined by the point of transition from coalescent to aggregate growth, only surface growth was applied to the Particles. The simulation results provide further support to the notion that Particle Nucleation and the presence of small Particles influence the morphology of primary Particles and the location of transition. It is demonstrated that the mean size of subParticles comprising the primary Particles is substantially smaller when using a realistic size distribution in the Nucleation zone of the investigated flame. This, in turn, reduces the degree of aggregation of the primary Particles at the time of transition to an extent that surface growth is able to recover their spherical shape in the post-Nucleation zone.
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detailed modeling of soot formation in laminar premixed ethylene flames at a pressure of 10 bar
Combustion and Flame, 1995Co-Authors: Andrei Kazakov, Hai Wang, Michael FrenklachAbstract:Abstract Detailed modeling of soot Particle Nucleation, growth and oxidation in laminar premixed ethylene-air flames at a pressure of 10 bar is presented. The employed kinetic model of soot formation, developed and tested earlier for subatmospheric and atmospheric flames, can quantitatively describe the experimental soot volume fraction profiles collected in a number of ehtylene flames at high pressures. The kinetic model consists of initial aromatic ring formation from nonaromatic species, planar polycyclic aromatic hydrocarbon (PAH) growth through the hydrogen-abstraction-acetylene-addition reaction mechanism, Particle Nucleation through coalescence of PAHs, Particle growth by coagulation and surface reactions of the forming clusters and Particles, and Particle oxidation. Analysis of the computational results obtained at 10 bar and additional tests performed for a 1-bar flame suggest that the influence of pressure on soot production arises mainly from the larger concentration of acetylene, which affects both the soot surface growth and the Nucleation of soot Particles.
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detailed modeling of soot Particle Nucleation and growth
Symposium (International) on Combustion, 1991Co-Authors: Michael Frenklach, Hai WangAbstract:Detailed modeling of soot Particle Nucleation and growth in laminar premixed hydrocarbon flames is presented. The model begins with fuel pyrolysis, followed by the formation of polycyclic aromatic hydrocarbons, their planar growth and coagulation into spherical Particles, and finally, surface growth and oxidation of the Particles. The computational results are in quantitative agreement with experimental results from several laminar premixed hydrocarbon flames. A detailed analysis of soot Particle inception and surface growth processes is presented. Surface growth was described in terms of elementary chemical reactions of surface active sites. The density of these sites was found to depend on the chemical environment. The model predicts the classical picture of soot Particle inception and the classical description of soot Particle structure.
Huixuan Zhang - One of the best experts on this subject based on the ideXlab platform.
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in situ charge neutralization controlled Particle coagulation and its effects on the Particle size distribution in the one step emulsion polymerization
European Polymer Journal, 2016Co-Authors: Wenting Meng, Mingyao Zhang, Huixuan Zhang, Ping WangAbstract:Abstract A novel approach to prepare sub-200 nm, narrowly dispersed polystyrene latex Particles is proposed for the emulsion polymerization of a ca. 40 wt% solid-content solution. The presented method exploits the cationic comonomer methacryloxyethyltrimethyl ammonium chloride (MATMAC) or the initiator 2,2′-Azobis (2-methylpropionamidine) dihydrochloride (AIBA) to generate cationic oligomeric radicals shielded the negatively charged surfactant molecules adsorbed on the Particles surface, further induced Particle coagulation by in situ charge neutralization. By adjusting the types and amounts of the comonomer, the extent of the in situ charge neutralization is controlled. In consequence, the extent of the Particle coagulation is controlled, resulting in the production of large-size latex Particles. The Particle coagulation induced by in situ charge neutralization occurs at the Particle Nucleation stage, which extends the times of Particle completive growth and reversible coagulation, and therefore, narrowed the width of the Particle size distribution of the ultimate latex Particles. The resulting colloidal latexes containing 40 wt% solid content are very stable by presenting the absolute value of zeta potentials larger than 40 mV. This approach is likely to be used for large-scale industrial productions of narrowly dispersed polymer Particles.
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Particle Nucleation and growth in the emulsion polymerization of styrene effect of monomer water ratio and electrolyte concentration
Journal of Macromolecular Science Part A, 2015Co-Authors: Baijun Liu, Mingyao Zhang, Yao Liu, Zhiyong Tan, Chao Zhou, Huixuan ZhangAbstract:This work is an extension of previous research results reported by our team (Colloid and Polymer Science 2013, 291: 2385-2398), where large scale and high solid content latexes of poly(n-butyl acrylate) were obtained with the Particle coagulation method induced by the electrolyte. However, how to prepare controlled Particle size distribution polymer latex has not been studied. Thus, in this study, the effect of the monomer/water ratios and electrolyte concentrations on Particle formation and growth methods were studied by following the tracks of the evolutions of Particle size, number and distribution as a function of reaction time or conversion. Experimental results showed that the length of time that Particle Nucleation occurred increased with increasing monomer charged for the systems without electrolyte. A point worthy of attention here is that homogeneous Nucleation may occur at high monomer concentrations (30/70, 40/60). However, electrolyte added could be made the Nucleation mechanism shift from mi...
Chorngshyan Chern - One of the best experts on this subject based on the ideXlab platform.
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miniemulsion copolymerizations of styrene and methyl methacrylate in the presence of reactive costabilizer
Journal of Applied Polymer Science, 2009Co-Authors: Chorngshyan Chern, H Lim, N A CalaAbstract:Miniemulsion stability of three-component disperse phase systems comprising styrene [ST (1)], methyl methacrylate [MMA (2)], and stearyl methacrylate [SMA (3)] was investigated. The Ostwald ripening rate (ω) increases with increasing MMA content in the monomer mixture. The empirical equation 1/ω = k(φ1/ω1 + φ2/ω2) + φ3/ω3 was proposed to adequately predict the miniemulsion stability data. The empirical parameter k was determined to be 555.77, and the Ostwald ripening rate (ω3) and water solubility of SMA were estimated to be 8.77 × 10−21 cm3/s and 1.90 × 10−9 mL/mL, respectively. A water-insoluble dye was used as a molecular probe to study Particle Nucleation mechanisms in the miniemulsion copolymerizations. In addition to the primary monomer droplet Nucleation, homogeneous Nucleation also plays an important role in the formation of Particle nuclei, and this mechanism becomes more important for the polymerization systems with higher MMA contents as a result of the enhanced aqueous phase polymer reactions. The polymer composition data suggest that, during the early stage of polymerization, MMA is consumed more rapidly by free radical polymerization compared with ST. The final latex Particle surface potential data also support this conclusion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
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principles and applications of emulsion polymerization
2008Co-Authors: Chorngshyan ChernAbstract:Preface. 1. Introduction. 1.1. Free Radical Polymerization. 1.2. Emulsion Polymerization. 1.3. Colloidal Stability. 1.4. Some Performance Properties for Industrial Applications. References. 2. Interfacial Phenomena. 2.1. Thermodynamic Consideration. 2.2. Surfactants. 2.3. Colloidal Stability. 3. Particle Nucleation Mechanisms. 3.1. Micellar Nucleation. 3.2. Homogenous Nucleation. 3.3. Coagulative Nucleation. 3.4. Mixed Mode of Particle Nucleation Mechanisms. 3.5. Surfactant-Free Emulsion Polymerization. 3.6. Experimental Work on Particle Nucleation. 3.7. Nonionic and Mixed Surfactant Systems. References. 4. Emulsion Polymerization Kinetics. 4.1. Emulsion Polymerization Kinetics. 4.2. Absorption of Free Radicals by Latex Particles. 4.3. Desorption of Free Radicals Out of Latex Particles. 4.4. Growth of Latex Particles. 4.5. Polymer Molecular Weight. References. 5. Miniemulsion Polymerization. 5.1. Polymerization in Monomer Droplets. 5.2. Stability of Monomer Emulsions. 5.3. Type of Costabilizers in Miniemulsion Polymerization. 5.4. Miniemulsion Polymerization Mechanisms and Kinetics. 5.5. Versatility of Miniemulsion Polymerization. References. 6. Microemulsion Polymerization. 6.1. Introduction. 6.2. Formation and Microstructure of Microemulsions. 6.3. O/W Microemulsion Polymerization. 6.4. W/O Microemulsion Polymerization. 6.5. Polymerization Continuous or Bicontinuous Phases of Microemulsions. References. 7. Semibatch and Continuous Emulsion Polymerizations. 7.1. Semibatch Emulsion Polymerization. 7.2. Continuous Emulsion Polymerization. 7.3. Development of Commercial Continuous Emulsion Polymerizations Process. References. 8. Emulsion Polymerizations in Nonuniform Latex Particles. 8.1. Origin of Nonuniform Latex Particles. 8.2. Seeded Emulsion Polymerizations. 8.3. Factors Affecting Particle Morphology. 8.4. Morphology Development in Latex Particles. 8.5. Polymerization Kinetics in Nonuniform Latex Particles. 9. Applications of Emulsion Polymers. 9.1. Physical Properties of Emulsion Polymers. 9.2. Rheological Properties of Emulsion Polymers. 9.3. Film Formation of Emulsion Polymers. 9.4. Foaming and Antifoaming Agents. 9.5. Wetting. 9.6. Surface Modifications. 9.7. Stability of Latex Products. Index.
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emulsion polymerization mechanisms and kinetics
Progress in Polymer Science, 2006Co-Authors: Chorngshyan ChernAbstract:Abstract Emulsion polymerization involves the propagation reaction of free radicals with monomer molecules in a very large number of discrete polymer Particles (10 16 –10 18 dm −3 ) dispersed in the continuous aqueous phase. The Nucleation and growth of latex Particles control the colloidal and physical properties of latex products. This review article focused on the polymerization mechanisms and kinetics involved in such a heterogeneous polymerization system over the preceding 10-year period. First, an overview of the general features of emulsion polymerization was given, followed by the discussion of several techniques useful for studying the related polymerization mechanisms and kinetics. Emulsion polymerizations using different stabilizers were studied extensively in the last few years and representative publications were reviewed. The performance properties of some specialty polymerizable, degradable or polymeric surfactants and surface-active initiators were also evaluated in emulsion polymerization. At present, the Particle Nucleation process is still not well understood and deserves more research efforts. This article continued to discuss the origin of non-uniform latex Particles from both the thermodynamic and kinetic points of view. This was followed by the discussion of various reaction parameters that had significant effects on the development of Particle morphology. Recent studies on the polymerization in non-uniform polymer Particles were then reviewed. Finally, the polymerization mechanisms, kinetics and colloidal stability involved in the versatile semibatch emulsion polymerization were reviewed extensively.
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Particle Nucleation and growth mechanisms in miniemulsion polymerization of styrene
Polymer International, 2002Co-Authors: Chorngshyan Chern, Hungte ChangAbstract:Styrene miniemulsion polymerizations stabilized by sodium lauryl sulfate in combination with a reactive costabilizer, lauryl methacrylate (LMA) or stearyl methacrylate (SMA), were studied. A small amount of extremely hydrophobic dye was incorporated into monomer droplets (102 nm in diameter) to investigate Particle Nucleation and growth mechanisms. In addition to monomer droplet Nucleation, Particle nuclei generated in the aqueous phase (homogeneous Nucleation) also play an important role in both LMA- and SMA-containing polymerization systems. The way that these two Nucleation mechanisms compete with each other is closely related to the water solubility of the costabilizer (LMA > SMA). The fraction of latex Particles originating from homogeneous Nucleation increases with decreasing hydrophobicity of the costabilizer. Zeta potential data of latex Particles and the molecular weight and molecular weight distribution of emulsion polymers provide supporting evidence for the proposed competitive Particle Nucleation and growth mechanisms. © 2002 Society of Chemical Industry
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Particle Nucleation loci in styrene miniemulsion polymerization using alkyl methacrylates as the reactive cosurfactant
Macromolecular Chemistry and Physics, 1998Co-Authors: Chorngshyan Chern, Yuhcherng Liou, T J ChenAbstract:A water-insoluble blue dye was used to study the Particle Nucleation mechanisms involved in the styrene miniemulsion polymerizations stabilized by sodium dodecyl sulfate (SDS) along with a reactive cosurfactant (e.g., dodecyl methacrylate (DMA) or stearyl methacrylate (SMA)). A mass balance was established to determine the number of latex Particles originating from the monomer droplets (N d ) and that of primary Particles generated in the aqueous phase (N w ). The accuracy of this method relies on producing a stable miniemulsion during the reaction. About 55% of the monomer droplets initially present in the reaction mixture (N m,i ) can be successfully converted into latex Particles for the system stabilized by SDS/DMA. The value of N d is much smaller than N w , Homogeneous Nucleation plays an important role in the reaction kinetics, but it becomes less significant when the DMA concentration is increased. On the other hand, the value of N m.i is much larger when the more hydrophobic SMA is chosen as the cosurfactant. As a consequence, Nucleation of primary Particles in the aqueous phase is greatly reduced. Nevertheless, only 49% of the original monomer droplets can be converted into latex Particles during polymerization. The value of N w is comparable to that of N d . Thus, the relatively large population of primary Particles generated via homogeneous Nucleation cannot be neglected for the SMA stabilized system. In addition, increasing the initiator concentration may enhance the degree of homogeneous Nucleation during the early stage of polymerization.