Photopolymerizable Monomer Miniemulsions: Why Does Droplet Size Matter?

Jasinski, Florent; Lobry, Emeline; Chemtob, Abraham; Croutxé‐Barghorn, Céline; Criqui, Adrien

doi:10.1002/macp.201300278

Cited by 27 publications

(40 citation statements)

References 25 publications

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“…S6) confirmed the increase of molecular weights of the formed block copolymers, indicating the successful secondary polymerization. The possible reason is that a certain amount of AIBN residuals are encapsulated in spherical micelles, which cannot be irradiated by UV light 28,29 to trigger 85 the polymerization. Furthermore, the successful thermal polymerization also indicated that the trithiocarbonate moieties in the system still had living character for further polymerization.…”

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confidence: 99%

UV light-initiated RAFT polymerization induced self-assembly

et al. 2015

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confidence: 99%

UV light-initiated RAFT polymerization induced self-assembly

et al. 2015

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“…[ 22 ] Scattering and absorption coeffi cients of acrylate miniemulsions were also determined in diluted [ 22 ] and concentrated [ 23 ] media using an integration sphere or the Kubelka-Munk theory, respectively. In this work, we employed a simple spectroscopic set-up to assess light penetration.…”

Section: Resultsmentioning

confidence: 99%

Flash Latex Production in a Continuous Helical Photoreactor: Releasing the Brake Pedal on Acrylate Chain Radical Polymerization

Chemtob

Lobry

Rannée

et al. 2016

Macromol. React. Eng.

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At the forefront is the radical chain polymerization, that represents 40% of all processes for the production of commercial polymers, including some of the most common plastics such as polystyrene, acrylic or vinyl polymers. It is of high interest that the propagation step governing the chain-growth may be very fast, given that the propagation rate coeffi cient ( k p ) is for most monomers in the range of 10 2 -10 4 L mol −1 s −1 . Nevertheless, the paradoxical observation is that polymer chemists have always strived to limit reactivity. The highly exothermic nature of radical chain polymerizations, the high activation energies involved, and the tendency toward the gel effect combine to make heat dissipation and polymer architecture control very challenging on an industrial scale. To avoid uncontrolled acceleration of the polymerization rate that may cause disastrous "runaway" reactions, the conventional approach consists in limiting the concentration of free monomer within the reactor through semicontinuous operations, with obvious adverse consequences for productivity. [ 2 ] With this limitation in mind, we have developed a novel eco-effi cient, "fl ash," radical chain linear photopolymerization, [ 1 ] able to reduce reaction time scales from hours to seconds. Our synergetic approach integrates macrofl ow photochemistry and emulsion-type polymerization . The result is a practical "single pass" helix photochemical reactor for the continuous photopolymerization of The continuous photopolymerization of acrylate and methacrylate monomer miniemulsions (25% solids content) is investigated at room temperature in a compact helix minireactor. Using n-butyl acrylate, the process yields 95% conversion after only 27 s residence time, and gel-free high-molecular-weight products. Under optimized conditions, a 25-fold increase in effi ciency is obtained when compared to a batch photopolymerization. The reaction set-up offers a frugal process because of moderate irradiance (2.6 mW cm −2 ), photoinitiator concentration (0.75 wt%), and low-power UV-A fl uorescent lamp.

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“…According to the Beer–Lambert law, the absorbance ( A ) at wavelength λ can be expressed by

A_{λ} = E_{λ} . l

where E is the attenuation coefficient, l the optical path length. The attenuation coefficient can be separated into three components; the absorption coefficient from C4AzoTAB ( K C 4 AzoTAB ), the absorption coefficient from PSt particles (swollen with monomer in case of incomplete conversion) ( K PSt ) and the scattering coefficient from PSt particles ( S PSt ):

E = K_{C 4 A z o T A B} + K_{P S t} + S_{P S t}

…”

Section: Methodsmentioning

confidence: 99%

Reversible Destabilization of UV‐Responsive Polymer Particles (Latex) using a Photoresponsive Surfactant

Jasinski

Guimarães

David

et al. 2019

Macromol. Rapid Commun.

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Production of aqueous dispersions of polymeric nanoparticles via heterogeneous radical polymerization in emulsion‐type systems is of enormous commercial importance. The ability to reversibly destabilize such a latex is highly desirable, for example, to save transportation costs. Herein, a method for synthesis of photo‐responsive polymer latexes that can be destabilized (leading to sedimentation) by only using UV irradiation (no addition of chemicals or change in the experimental conditions) and subsequently redispersed by stirring under visible light irradiation is described. The destabilization/redispersion mechanism relies on photoinduced trans‐cis isomerization of the cationic diazene surfactant 2‐(4‐(4‐butylphenyl)diazenylphenoxy)ethyltrimethylammonium bromide (C4AzoTAB) used in conjunction with the anionic surfactant sodium dodecyl sulfate. It is demonstrated that reversible destabilization can be achieved very rapidly (90 s residence time) employing continuous flow technology.

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Photopolymerizable Monomer Miniemulsions: Why Does Droplet Size Matter?

Cited by 27 publications

References 25 publications

UV light-initiated RAFT polymerization induced self-assembly

UV light-initiated RAFT polymerization induced self-assembly

Flash Latex Production in a Continuous Helical Photoreactor: Releasing the Brake Pedal on Acrylate Chain Radical Polymerization

Reversible Destabilization of UV‐Responsive Polymer Particles (Latex) using a Photoresponsive Surfactant

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