Compartmentalization minimizes radicalradical termination events and droplet nucleation eliminates the mass. Miniemulsion polymerization and the structure of polymer and hybrid nanoparticles. Microemulsion polymerization is a complex heterogeneous process where transport of monomers, free radicals and other species such as chain transfer agent, cosurfactant and inhibitors between the aqueous and organic phases, takes place. However, these results are consistent with a mechanism in which the radicals. Dec 18, 2009 the miniemulsion technique now provides a possibility to obtain nanoparticles at high solid contents, a functionalization of the nanoparticles is possible by nucleophiles initiating the anionic polymerization of the miniemulsion droplets, and additionally, an encapsulation of various materials is easily possible. The polymerization rate of raftmediated miniemulsion polymerization, in which the time fraction of active radical. This paper highlights the ability of miniemulsion polymerization to produce. The model predictions are verified against data taken from the literature. Abstract emulsion polymers are products by process whose main properties.
Pdf in miniemulsion polymerization, droplet nucleation is the key factor to ensure the production of polymer particles with a desired. Raft microemulsion polymerization with surfaceactive chain transfer agent by ibrahim adnan elhedok a dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of doctor of philosophy major. Formulation and characterization of microemulsion based gel. Influence of monomer partitioning, termination, and diffusion limitations on polymerization kinetics. The ultrasonically initiated batch miniemulsion copolymerizations of methyl methacrylate mma and butyl acrylate ba are studied at different mma.
Dec 01, 2010 the miniemulsion technique is a particular case in the family of heterophase polymerizations, which allows the formation of functionalized polymers by polymerization or modification of polymers in stable nanodroplets. From polymeric particles to multifunctional nanocapsules for. A population balance model for miniemulsion polymerization. In this study, free radical miniemulsion copolymerization of ethylene and vinyl acetate vac is reported. A miniemulsion also known as nanoemulsion is a special case of emulsion. Miniemulsion polymerization for synthesis of structured claypolymer. Polymerization of styrene miniemulsions, prepared using a mixed emulsifier system comprising sodium lauryl sulfate and cetyl alcohol, was carried out using both water.
The best results were obtained using the raft agent 3benzylsulfanyl thiocarbonyl sufanylpropionic acid bspac, most likely as a result. Similarly, sodium acrylate was polymerized in inverse. Miniemulsion copolymerization of methyl methacrylate and. In this work, we examined the inverse miniemulsion polymerization of acrylamide with the cationic. Welding engineering and technology joining of plastics and composites mladen sercer, pero raos encyclopedia of life support systems eolss commercially available welding processes, this text helps the reader select the bestsuited process for the application and provides an understanding on the limitations and benefits of each process. The miniemulsion technique now provides a possibility to obtain nanoparticles at high solid contents, a functionalization of the nanoparticles is possible by nucleophiles initiating the anionic polymerization of the miniemulsion droplets, and additionally, an encapsulation of various materials is easily possible. The emulsion polymerization mechanism is divided in two main stages. Encapsulation by miniemulsion polymerization springerlink. Results showed the feasibility of online monitoring of conversion and average particle size in these inverse miniemulsion polymerization reactions using nir spectroscopy. A new approach to the synthesis of hydrophobically.
Raft microemulsion polymerization with surfaceactive chain. Photoreversible fluorescent modulation of nanoparticles via onestep miniemulsion polymerization. Miniemulsion polymerization for synthesis of structured clay. Miniemulsion polymerization has recently grown from its initial reporting to being the focus of mush industrial and. Miniemulsion polymerization has recently grown from its initial reporting to being the focus of mush industrial and academic research2. In theory, a miniemulsion comprises the ideal environment for living radical polymerization by the raft process. An advanced approach on the study of emulsion polymerization.
Population balance model, miniemulsion, polymerization miniemulsions are comprised of relatively stable. In this study, we show that miniemulsion photopolymerization provides a suitable method to create latex without the apparent addition of these three compounds. Miniemulsion polymerization as a versatile tool for the. The monomer miniemulsions herein include, in addition to water, a surfactant, and a monomer or mixture thereof, one or more polymers which function as a. Miniemulsion polymerization as a means to encapsulate organic and inorganic materials article pdf available in advances in polymer science 233 january 2011 with 1,592 reads how we measure reads. Depending on reaction parameters, particle coagulation is also able to produce. Polymer synthesis 2 centre for advanced macromolecular. These hybrid particles were an attempt to combine these properties. Miniemulsion copolymerization of ethylene and vinyl acetate. A miniemulsion is obtained by shearing a mixture comprising two immiscible liquid phases for example, oil and water, one or more surfactants and, possibly, one or more cosurfactants typical examples are hexadecane or cetyl alcohol.
The goal of this study is to investigate the feasibility to enhance the ethylene incor poration using an environmentalfriendly miniemulsion polymerization technique. A population balance model for the miniemulsion polymerization that incorporates the particle size distribution is developed in this work. Recipe for the batch miniemulsion polymerization of styrene 63 table 3. The monomer emulsions prepared for hybrid miniemulsion polymerization showed excellent shelflife stability up to 5 months and the polymerization was run free of coagulation. The main objective of this mqp was to follow the reaction kinetics of the polymerization reaction of mma in miniemulsions.
The dose rate and the total absorbed total dose were found to affect the particle size of the latex particles. The use of nir spectroscopy for monitoring acrylamide inverse miniemulsion polymerization was discussed in this work. Definition and history one of the best definitions of microemulsions is from danielsson and lindman 1 a microemulsion is a system of water, oil and an amphiphile which is a single optically isotropic and thermodynamically stable liquid solution. Particle formation in the former is a mixture of micellar and homogeneous nucleation, particles formed via miniemulsion however are mainly formed by droplet nucleation. Synthesis of nanoscale materials through miniemulsion. Miniemulsion is an important class of emulsions that are stabilized against coalescence using surface active agents and the effect of ostwald ripening. Explains miniemulsion technology and techniques and why they have many distinct advantages over the conventional emulsion polymerization technology miniemulsion polymerization technology comprises 10 papers by many of the worlds experts on the subject.
Synthesis of polymeric nanoparticles via co 2induced miniemulsion polymerization. In situ visualization and realtime tracking of emulsion and. The products will exhibit higher thickening ability. This was done by carrying out mma miniemulsion polymerization reactions and taking samples at different times. Jan 25, 2011 explains miniemulsion technology and techniques and why they have many distinct advantages over the conventional emulsion polymerization technology miniemulsion polymerization technology comprises 10 papers by many of the worlds experts on the subject. This approach has been widely used in academic and industrial research owing to its higher polymerization rate and onestep polymerization process. The classical emulsion and miniemulsion polymerization of styrene were conducted by onestep processes. An essentially stable monomer miniemulsion characterized by small monomer droplet size is prepared and is then polymerized to a polymer latex under free radical polymerization conditions. In miniemulsion polymerization for the preparation of polymer colloids latexes, since the surfactant concentration in the aqueous phase is below the cmc, the submicron monomer droplets are the main sites for particle nucleation and growth via free radical initiation using oilsoluble or watersoluble initiators.
In the pharmaceutical industry, oil droplets act as tiny containers that carry waterinsoluble drugs, and the water provides a mild environment that is compatible with the human body. Miniemulsion polymerization and the structure of polymer and. Faridimajidi r, sharifisanjani n 2007 emulsifierfree miniemulsion polymerization of styrene and the investigation of encapsulation of nanoparticles with polystyrene via this procedure using an anionic initiator. Tracking droplet nucleation in seeded semibatch miniemulsion polymerization m. Kinetics of polymerization reaction in miniemulsions a major. The percent polymer was calculated once the samples were freezedried, which removed the monomer and left only the. The initiator potassium peroxodisulfate kps could not be used due to its low solubility in the 2hydroxyethyl methacrylate monomer. Miniemulsion polymerization matyjaszewski polymer group. Microbiology and immunology dept, university of otago, dunedin, new zealand evaporationcontrolled. Predictions for particle size and molecular weight distributions kinetic. Reversible additionfragmentation chain transfer raft polymerization of styrene has been implemented in aqueous miniemulsion based on the in situ surfactant generation approach using oleic acid and potassium hydroxide in the absence of high energy mixing. The aim of this research stream is to develop energyefficient, environmentally friendly and versatile methods for synthesis of polymer and polymeric nanoparticles via miniemulsion polymerization.
A is larger than a few percent, basically increases with reducing the particle. Photomediated atom transfer radical polymerization photoatrp of methacrylic monomers was conducted in miniemulsion media. Mar 16, 2010 faridimajidi r, sharifisanjani n 2007 emulsifierfree miniemulsion polymerization of styrene and the investigation of encapsulation of nanoparticles with polystyrene via this procedure using an anionic initiator. A small vial with an inner diameter of 12 mm was used to run a miniemulsion with 3 ml volume, whereas a larger vial with a diameter of 25 mm contained 10 ml of miniemulsion figure s1. Colloidal particles with a controlled morphology combining both organic and inorganic parts were synthesized through a seeded emulsion polymerization process. Pdf particle nucleation using different initiators in the. In the presence of template, the oppositely charged monomer can form a longer hydrophobic block along the polymer chains. A process for preparing an aqueous polymer dispersion by freeradically initiated polymerization of freeradically polymerizable compounds i with moderate solubility in water, whose disperse polymer particles contain not only compounds i but also compounds ii with a very low solubility in water where a mixture consisting of a portion of the compounds i and consisting of the compounds ii is. Inverse miniemulsion polymerization refers to systems in which the continuous medium is an organic. When finally processed to provide the function for which the latex was selected. Particle coagulation is a facile approach to produce largescale polymer latex particles. Polyurethane 2 wt % was used as the hydrophobe in the miniemulsion polymerization of styrene and was sufficient to ensure a shelflife of 1 year for the miniemulsion 127. Trends in the evolution of the particle number are rationalized with reference to the mechanical properties of. Detection, estimation, and modulation theory part 4.
In some respects, microemulsions can be considered as smallscale. Shah college of pharmaceutical education and research dhansura road college campus modasa, dist. Formulation and characterization of microemulsion based gel of antifungal drug patel rahul r. Combining the viscosity equation with a polymerization model. Ylike branched surfactant were synthesized and used for. Photoinduced miniemulsion atom transfer radical polymerization. The miniemulsion technique is a particular case in the family of heterophase polymerizations, which allows the formation of functionalized polymers by polymerization or modification of polymers in stable nanodroplets. In both cases 126,127, the particle size and distribution were preserved throughout the polymerization. In this work, we examined the inverse miniemulsion polymerization of. After stirring for 10 min at room temperature, the emulsion was heated at 80 c for 8 h. The free radical polymerization of the dithiobenzoateendcapped oligomers in the miniemulsion proceeded in a controlled manner with molecular weight increasing in a linear fashion with increasing conversion, while polydispersities remained low. Kaler center for molecular and engineering thermodynamics, department of chemical engineering, university of delaware, newark, delaware 19716.
In miniemulsion polymerization for the preparation of polymer colloids latexes, since the surfactant concentration in the aqueous phase is below the cmc, the submicron monomer droplets are the main sites for particle nucleation and growth via free radical. Miniemulsion polymerization has recently exploded in terms of publications and the. Miniemulsion polymerization technology wiley online books. Living radical polymerization in miniemulsion using. Miniemulsion me polymerization represents an alternative for the synthesis of hybrid latexes and enables the incorporation of a hydrophobic component into the polymer particles without requiring its diffusion through the aqueous phase asua 2002. Reversible additionfragmentation chain transfer polymerization in microemulsion shiyong liu, kevin d.
A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Nanocapsules below 100 nm with liquid cores and molar mass controlled polystyrene shells were synthesized by an in situ miniemulsion polymerization reaction in the presence of a raft reversible addition fragmentation chain transfer agent. Most miniemulsion polymerizations are carried out in batch reactors. Living radical polymerization in miniemulsion using reversible additionfragmentation chain transfer. Kaler center of molecular engineering and thermodynamics, department of chemical engineering, university of delaware, newark, delaware 19716 received december 16, 2005. The polymerization procedures took advantage of an ionpair catalyst formed by interaction of cutpma2 tpma tris2pyridylmethylamine and an anionic surfactant, sodium dodecyl sulfate sds. The idea of the procedure is that the hydrophobe and monomer form a common miniemulsion, whereas the polymer is immiscible with the hydrophobe and demixes throughout polymerization to form the hollow polymer structure surrounding the hydrophobe. Ba ratios including homopolymerizations, and the physical properties and chemical composition of the polymers formed are investigated. Emulsion polymerization ep is a complex heterophase process which involves many components and also runs sequentially and in parallel physicochemical processes that determine the composition of the emulsion, the formation mechanism of polymermonomeric particles pmp, conditions for the formation of interfacial layer, etc.
Preparation of polymeric nanocapsules by miniemulsion. Materials and methods chemical styrene st, 99%, supplied by the shanghai chemical reagent corporation shanghai, china, was distilled under vacuum to remove the inhibitors prior to polymerization and used as the monomer. Emulsion and miniemulsion polymerization stabilized. Initiator systems effect on particle coagulation and particle. Miniemulsion polymerization has recently exploded in terms of publications and the development of a wide range of useful polymer materials only accessible through this polymerization technique. In miniemulsion polymerization, 10 g of st and 500 mg of aibn were mixed in a flask and 100 ml of deionized water was added for emulsification. It summarizes the recent advances in miniemulsion polymerization technology including the advances on the selection of surfactants and cosurfactants, the expansion of miniemulsion technology in various polymers and copolymer systems, and the use of miniemulsion polymerization for the synthesis of advanced polymer particle morphologies. Citescore values are based on citation counts in a given year e. According to this mechanism, a minimum amount of fatty alcohol is needed to. Nevertheless, while the number of works involving direct miniemulsion polymerization oil in water has increased dramatically since the pioneering work of ugelstad et al. Our work was motivated to control the extent or time of particle coagulation. Controlled free radical polymerization in miniemulsion using. Us5686518a miniemulsion polymerization process using. Us6160049a emulsion polymerization process with combination.
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