Emulsion Polymerization: Kinetic and Mechanistic Aspects

Nomura, Mamoru; Tobita, Hidetaka; Suzuki, Kiyoshi

doi:10.1007/b100116

Cited by 120 publications

(87 citation statements)

References 3 publications

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“…At the same time, the polymerization rate decreased because of the decrease in the rate of the radical entering the polymer particles. This interpretation was analogous to the modified Morton equation reported by Nomura et al [27] In contrast, from the thermodynamics view, the addition of methanol could reduce the interfacial tension between the polymer particles and aqueous phase. [28] With increasing methanol content, the surface tension of medium phase decreased from 71.98 mN/m in pure water to 58.3 and 49.05 mN/m in 10 and 20 wt% methanol solution, respectively.…”

Section: Effect Of Reaction Kinetics In Aqueous Phase On Particle Coasupporting

confidence: 83%

A novel approach to prepare large-scale and narrow-dispersed latex particles by emulsion polymerization based on particle coagulation mechanism

Liu

Deng

Sun

et al. 2015

Designed Monomers and Polymers

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In order to understand the mechanism of narrow particle size distribution of the final latex during particle coagulation, a series of experiments were performed to investigate the effect of polymer nature on particle coagulation capability. In particular, thermodynamics and kinetics in aqueous phase were considered to illustrate the detail process of particle coagulation. The final particle size decreased with the increasing side chain length of alkyl methacrylate from 181.5 nm in MMA to 131.6 nm in EMA, 119.3 nm in PMA, and 115.1 nm in BMA, indicating that the particle coagulation capability was proportional to the hydrophilicity of polymer. With increasing polymer hydrophilicity, the affinity between surfactant molecules and particle surface decreased, thus enhancing the particle coagulation capability. Moreover, the critical length of oligomer radical also increased with increasing hydrophilicity and the efficiency of radical capture decreased, thus increasing the saturation of monomer concentration in the inner part of particle, promoting particle coagulation. Combining these results and the La Mer Diagram, a novel approach was developed to prepare large-scale, narrow-dispersed, and high solid content polymer latex based on particle coagulation mechanism. Three criteria, namely, rapid nucleation, fast coagulation, and a long growth period, should be met to produce latex with a narrow particle size distribution.

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Section: Effect Of Reaction Kinetics In Aqueous Phase On Particle Coasupporting

confidence: 83%

A novel approach to prepare large-scale and narrow-dispersed latex particles by emulsion polymerization based on particle coagulation mechanism

Liu

Deng

Sun

et al. 2015

Designed Monomers and Polymers

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“…Three major mechanisms for particle formation have been proposed to date. Particle formation is considered to have taken place when (1) a free radical in the aqueous phase enters a monomer-swollen emulsifier micelle and propagation proceeds therein or; (2) the chain length of a free radical growing in the aqueous phase exceeds its solubility limit and precipitates to form a particle nucleus, or; (3) a free radical growing in the aqueous phase enters a monomer droplet and propagation proceeds therein [53].…”

Section: Emulsion/miniemulsion Polymerizationmentioning

confidence: 99%

Review of solid–liquid phase change materials and their encapsulation technologies

Darkwa

Kokogiannakis

2015

Renewable and Sustainable Energy Reviews

777

267

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Various types of solid-liquid phase change materials (PCMs) have been reviewed for thermal energy storage applications. The review has shown that organic solid-liquid PCMs have much more advantages and capabilities than inorganic PCMs but do possess low thermal conductivity and density as well as being flammable. Inorganic PCMs possess higher heat storage capacities and conductivities, cheaper and readily available as well as being non-flammable, but do experience supercooling and phase segregation problems during phase change process. The review has also shown that eutectic PCMs have unique advantage since their melting points can be adjusted. In addition, they have relatively high thermal conductivity and density but they possess low latent and specific heat capacities. Encapsulation technologies and shell materials have also been examined and limitations established. The morphology of particles was identified as a key influencing factor on the thermal and chemical stability and the mechanical strength of encapsulated PCMs. In general, in-situ polymerization method appears to offer the best technological approach in terms of encapsulation efficiency and structural integrity of core material. There is however the need for the development of enhancement methods and standardization of testing procedures for microencapsulated PCMs. Abstract: Various types of solid-liquid phase change materials (PCMs) have been reviewed for thermal energy storage applications. The review has shown that organic solid-liquid PCMs have much more advantages and capabilities than inorganic PCMs but do possess low thermal conductivity and density as well as being flammable. Inorganic PCMs possess higher heat storage capacities and conductivities, cheaper and readily available as well as being non-flammable, but do experience supercooling and phase segregation problems during phase change process. The review has also shown that eutectic PCMs have unique advantage since their melting points can be adjusted. In addition they have relatively high thermal conductivity and density but they possess low latent and specific heat capacities. Encapsulation technologies and shell materials have also been examined and limitations established. The morphology of particles were identified as a key influencing factor on the thermal and chemical stability and the mechanical strength of encapsulated PCMs. In general, in-situ polymerization method appears to offer the best technological approach in terms of encapsulation efficiency and structural integrity of core material. There is however the need for the development of enhancement methods and standardization of testing procedures for microencapsulated PCMs.

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“…The observed effect of the dropping rate to the size of the particles can be explained by the microencapsulation mechanism of the n-octadecane, which involves formation of micelles through dispersion of n-octadecane particles in water with the aid of anionic SDS [18]. From this emulsification, the n-octadecane micelles will gain negative charges due to the hydrophilic sulfate ion, while the methylolation products of melamine or urea with the formaldehyde will gain positive charges due to the acidified environment [19].…”

Section: A Ftir and Sem Analysis Of Mepcmsmentioning

confidence: 99%

Characterization of MEPCM-Incorporated Paint as Latent Heat Storage System

Tumolva¹,

Sabarillo²

2017

IJCEA

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Abstract-This study aimed to determine the effect of the mixing speed and pre-polymer dropping rate during synthesis of microencapsulated phase change materials (MEPCMs), and to assess the performance of MEPCM-incorporated paint as a latent heat storage (LHS) system. N-octadecane as phase change material was encapsulated with resorcinol-modified ureamelamine-formaldehyde at two different mixing speeds and four different pre-polymer dropping rates, and Fourier transform infrared (FTIR) spectroscopy was done to confirm success of microencapsulation. Scanning electron microscopy (SEM) revealed that increasing the homogenization speed and decreasing the pre-polymer dropping rate decreases the microcapsule size. Differential scanning calorimetry results showed that latent heat and encapsulation ratio increases with increasing mixing speed and decreasing pre-polymer dropping rate. The synthesized MEPCMs were incorporated into white paint at three different concentrations, and temperature profiling revealed that the paint's temperature buffering capacity generally increases with increasing mixing speed, decreasing pre-polymer dropping rate and increasing MEPCM concentration.Index Terms-Heat storage, MEPCM, phase change material, microencapsulation.

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Emulsion Polymerization: Kinetic and Mechanistic Aspects

Cited by 120 publications

References 3 publications

A novel approach to prepare large-scale and narrow-dispersed latex particles by emulsion polymerization based on particle coagulation mechanism

A novel approach to prepare large-scale and narrow-dispersed latex particles by emulsion polymerization based on particle coagulation mechanism

Review of solid–liquid phase change materials and their encapsulation technologies

Characterization of MEPCM-Incorporated Paint as Latent Heat Storage System

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