Use of α‐diketones as visible photoinitiators for the photocrosslinking of waterborne latex paints

Abstract

The efficiency of several α‐diketones as visible light photoinitiators for the crosslinking of waterborne latex dispersions in the presence of acrylic monomers was evaluated. Among the eight α‐diketones studied, camphorquinone allows the fastest curing speed, and the curing of the acrylic waterborne coating is not affected by the presence of oxygen. The properties of the sunlight‐cured volatile organic compound (VOC)‐free pigmented paints prepared from the waterborne latex are as good or better than the equivalent conventional paint containing VOCs. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3171–3181, 2002

Balancing the Initiation and Molecular Recognition Capabilities of Eosin Macroinitiators of Polymerization‐Based Signal Amplification Reactions

“…[1][2][3][4] Cost, ease-of-use, and performance are each of major importance for wide adoption of detection platforms and techniques. [5] With these criteria in mind, we and others have developed polymerization-based signal amplification [6][7][8][9] as a method that provides rapid (< 1 min) and unambiguous visualization of results in RDTs using low-cost chemistry that is currently used in a wide variety of inexpensive consumer products [10][11][12] . In polymerizationbased amplification (PBA), initiators of radical polymerization reactions are localized as a function of molecular recognition events, and upon activation using light, a cross-linked hydrogel forms from an aqueous monomer solution.…”

Catalytic Asymmetric Synthesis of Fluoroalkyl‐Containing Compounds by Three‐Component Photoredox Chemistry

“…[15] Particularly,diacetyl is very appealing for visible-light-induced SET but the requirement to use it as ac osolventp oses as ignificant drawback. Inspiredb yt his work, we envisioned an asymmetrict hree-component fluoroalkylation reactions cheme under photoredoxc onditions using an inexpensive readily available a-diketone [16] with improved photoredox properties. The reaction designi so utlined in Figure 2a nd based on our previouse xperience with asymmetric photoredox catalysis.…”

“…The reaction designi so utlined in Figure 2a nd based on our previouse xperience with asymmetric photoredox catalysis. [13,14] Accordingly,aphotoexcited a-diketone, presumably bearing an extended p-systemw ith aryl substituents to improvev isible light absorption [16] and stabilize radicala nion intermediates, should be quenched reductively by the Langlois reagent (1) [17] or related sodium perfluoroalkyl sulfinates [18] to generate ap erfluoroalkyl radicala long with ak etyl radical. The electron-deficient fluorinated radical is then selectively trapped by the electron-rich terminal alkene 2 to provide under CÀCb ond formation an a-oxy carbon-centered radical speciesw hich subsequently engages in ar hodium-catalyzed asymmetrica ddition to an acceptor-substituted alkene (Rh-I!Rh-II)t oc reate a second CÀCs ingleb ond in an enantioselective and diastereoselectivef ashion.S ET from the reduced photoredox mediator (ketyl intermediate) to the rhodium-coordinated radical (Rh-II) followed by protonation then provides the rhodium-coordinated product (Rh-III)a ccompanied with ar egenerated a-diketone.…”

Photopolymerization Reactions: On the Way to a Green and Sustainable Chemistry

“…For example, the development of sunlight photosensitive formulations (see, e.g., [77][78][79][80][81][82][83][84][85] and references therein; see also the patent literature aiming at industrial applications) for the drying of paints for crack-bridging applications, anti-soiling properties, the manufacture of interpenetrating polymer networks (IPN) usable as protective coatings and glues, the fabrication of glass fiber reinforced composites, hard and rigidified four layer glass cloth laminate, clearcoats and polymer-clay composites has been realized in the past, but these systems, except some of them (e.g., those described in [79,80,84]) suffer from oxygen inhibition and a relatively low photosensitivity.…”