Divinyl Ether Monomers Research Articles

Photoinitiation Mechanism and Ability of Monoamino-Substituted Anthraquinone Derivatives as Cationic Photoinitiators of Polymerization under LEDs.

The design and development of photoinitiating systems applicable to UV or even visible light delivered from light-emitting diodes (LEDs) has been attracting increasing attention due to their great potential applications in various fields. Compared to the strategy of synthesizing novel compounds, the exploration of existing chemicals with interesting photochemical/photophysical properties for their usage as photoinitiators is more appealing and easily commercialized. Nevertheless, a number of compounds such as monoamino-substituted anthraquinone derivatives, which are intensively investigated for their photophysical and photochemical properties, have seldom been studied for their roles as photoinitiators under LED irradiation. Herein, three monoamino-substituted anthraquinone derivatives, that is, 1-aminoanthraquinone, 1-(methylamino)anthraquinone and 1-(benzamido)anthraquinone, are studied for their potential as photoinitiators. The photoinitiation mechanism of these monoamino-substituted anthraquinone derivatives, when combined with iodonium salt, is first clarified using computational quantum chemistry, fluorescence, steady-state photolysis, and electron spin resonance spin-trapping techniques. Then, their photoinitiation ability for the cationic photopolymerization of epoxide and divinyl ether monomers is also investigated.

Applicability of samarium(III) complexes for the role of luminescent molecular sensors for monitoring progress of photopolymerization processes and control of the thickness of polymer coatings

Applicability of 15 trivalent samarium complexes as novel luminescent probes for monitoring progress of photopolymerization processes or thickness of polymer coatings by the Fluorescence Probe Technique (FPT) was studied. Three groups of samarium(III) complexes were evaluated in cationic photopolymerization of triethylene glycol divinyl ether monomer (TEGDVE) and free-radical photopolymerization of trimethylolpropane triacrylate (TMPTA). The complexes were the derivatives of tris(4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate)samarium(III), tris(4,4,4-trifluoro-1-phenyl-1,3-butanedionate)samarium(III) and tris(4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedionate)samarium(III), which were further coordinated with auxiliary ligands, such as 1,10-phenanthroline, triphenylphosphine oxide, tributylphosphine oxide and trioctylphosphine oxide. It has been found that most of the complexes studied are sensitive enough to be used as luminescent probes for monitoring progress of cationic photopolymerization of vinyl ether monomers over entire range of monomer conversions. In the case of free-radical polymerization processes, the samarium(III) complexes are not sensitive enough to changes of microviscosity and/or micropolarity of the medium, so they cannot be used to monitor progress of the polymerization. However, high stability of luminescence intensity of some of these complexes under free-radical polymerization conditions makes them good candidates for application as thickness sensors for polymer coatings prepared by free-radical photopolymerization. A quantitative relationship between a coating thickness and the luminescence intensity of the samarium(III) probes has been derived and verified experimentally within a broad range of the thicknesses.

Synthesis of polymeric microcapsules by interfacial-suspension cationic photopolymerisation of divinyl ether monomer in aqueous suspension

Polymeric microcapusles have been synthesised with a markedly more hydrophillic monomer than previously reported, triethylene glycol divinyl ether, using cationic photopolymerisation in an aqueous environment.

Thiol‐Ene Step‐Growth as a Versatile Route to Functional Polymers

AbstractA new use of the thiol‐ene reaction to generate functional, redox‐tunable polymers is described. To illustrate the versatility of this approach, tailored divinyl ether monomers were polymerized with triethylene glycol dithiol to yield polymers containing either a carbonate or zwitterionic phosphocholine within the polymer backbone. Similarly, dithioerythritol was polymerized with triethylene glycol divinyl ether to yield a polymer with pendant diols and show how functional groups can be designed into either the divinyl ether or dithiol monomer. Using the thioether functional group inherent to this polymerization, all three polymers were selectively and quantitatively oxidized to either sulfoxides or sulfones by treatment with dilute hydrogen peroxide or mCPBA, respectively. With these illustrative examples, it is shown that the thiol‐ene polymerization is a broad‐reaching method to access a class of new redox‐active polymers which contain varied and dense functional‐group compositions.

Thiol-Ene Step-Growth as a Versatile Route to Functional Polymers.

A new use of the thiol-ene reaction to generate functional, redox-tunable polymers is described. To illustrate the versatility of this approach, tailored divinyl ether monomers were polymerized with triethylene glycol dithiol to yield polymers containing either a carbonate or zwitterionic phosphocholine within the polymer backbone. Similarly, dithioerythritol was polymerized with triethylene glycol divinyl ether to yield a polymer with pendant diols and show how functional groups can be designed into either the divinyl ether or dithiol monomer. Using the thioether functional group inherent to this polymerization, all three polymers were selectively and quantitatively oxidized to either sulfoxides or sulfones by treatment with dilute hydrogen peroxide or mCPBA, respectively. With these illustrative examples, it is shown that the thiol-ene polymerization is a broad-reaching method to access a class of new redox-active polymers which contain varied and dense functional-group compositions.

Polyacetals: Water-Soluble, pH-Degradable Polymers with Extraordinary Temperature Response

Temperature-responsive polymers exhibit a drastic change in solubility upon change in temperature, a property responsible for their increased use in a wide variety of emerging smart material applications. Here, we describe a flexible new family of polyacetals with lower critical solution temperature (LCST) behavior, falling out of aqueous solution upon increase in temperature. These are the first synthetic LCST polymers to be intrinsically biodegradable, forming neutral degradation products in acidic environments. The temperature response of the polyacetals is extraordinary. Their LCST cloud point temperatures can be predicted and tuned to high precision over a temperature range of ca. 6–80 °C as they are linearly dependent on the number of methylene and ethylene oxide units in the diol and divinyl ether monomers. We further demonstrate that the LCST temperatures are insensitive to salt and/or polymer concentration, properties that are important to in vivo applications, and that they are biocompatible.

Photo‐Plasticity in Thiol‐ene Network Polymers – A Review

AbstractIn this paper we briefly overview the area of stimuli responsive polymers and the subset of photo‐plastic polymers which change shape or undergo stress relaxation during irradiation. The chemistry, mechanism and properties of a new class of photo‐plastic polymers is presented in detail – these tetrathiol‐diene networks contain an allylic dithioether (also termed allylic disulphide) unit in the network strands and when this moiety is attacked by a photogenerated radical, the allylic dithioether undergoes β‐cleavage which breaks one network bond and reforms another. Two different methods of integration of the allylic dithioether unit into the backbone are investigated – the use of a cyclic allylic dithioether which copolymerizes with a thiol‐ene system or the incorporation of the allylic dithioether moiety in a divinyl ether monomer which can directly copolymerize with the thiol. The photo‐plasticity effect of these thiol‐ene networks is revealed in both creep and stress relaxation experiments, however, the extent of photo‐plasticity is less extensive than expected. The polymerization kinetics and evolution of the rheological properties during photocuring are studied and the slower copolymerization of the monomer containing the allylic dithioether is discussed. The photo‐rheology and dynamic mechanical properties of the thiol‐ene networks are interpreted in terms of the network structure.

Photopolymerization kinetics, photorheology and photoplasticity of thiol–ene–allylic sulfide networks

AbstractBACKGROUND: Thiol–ene networks are of interest due to their facile photopolymerization and their open network structure. In this work, an allylic disulphide divinyl ether monomer is reacted with tetrathiol and divinyl ether monomers, which allows the network structure to permanently change in shape if stressed while under irradiation. We also study the photo‐differential scanning calorimetry (DSC) kinetics and photorheology during cure and the dynamic mechanical properties after cure.RESULTS: The heat of polymerization is similar for the thiol–ene systems and suggests ca 80% conversion of the vinyl ether groups. An increase in the initiator concentration increases the photocure rate as expected. The activation energy for photopolymerization is 7.6 kJ mol−1. DSC and rheometry studies show that the polymerization kinetics is slowed by the addition of the allylic disulfide divinyl possibly due to the formation of less reactive radicals. However, as shown by dynamic mechanical thermal analysis, the network structure is not changed very much by addition of this monomer. If radicals are generated by irradiation of a photoinitiator in the network while a stress is being applied, the polymer will permanently deform depending on the fraction of 2‐methylenepropane‐1,3‐di(thioethyl vinyl ether) in the network, due to a bond interchange reaction.CONCLUSION: The rate of thiol–ene reaction is slowed by the addition of the allylic disulfide divinyl ether. Photoplasticity is observed in the networks containing the allylic disulfide groups. Further work is required to optimize the extent of photoplasticity in these systems. Copyright © 2007 Society of Chemical Industry

UV-Härtung von Beschichtungsstoffen basiert auf Vinylether

The photoinitiated polymerisation of different types of vinyl ether-based resins has been studied by real-time infrared spectroscopy. The cationic initiated chain reaction was shown to proceed extensively within seconds, on UV exposure of divinyl ether monomers in the presence of on arylsulfonium salt. Various factors affect the polymerisation kinetics, such as the type of photoinitiator, the light intensity and the viscosity of the mixture. Different kinds of tridimensional polymer networks have been produced by the UV-curing of hybrid systems made from a vinyl ether (VE) and a co-monomer. With triaaylate monomers associated with divinyl ethers, interpenetrating polymer networks or cross-linked copolymers with isolated VE units were generated, depending on the type of photoinitiator used. In the presence of electron acceptor monomers, such as maleates or maleimides, vinyl ether monomers undergo a ready copolymerisation on UV irradiation, by a radical-type mechanism, with the formation of an alternating copolymer.

Novel copolymer networks via the combination of polyaddition and anionic polymerization

A two-step synthetic route to novel copolymer networks, consisting of polymethacrylate and polyacetal components, was developed by combining the polyaddition and anionic polymerization techniques. The functional polymethacrylates containing hydroxyl or vinyloxyl side groups were used as crosslinkers. They were anionically synthesized as follows: the copolymer of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) was prepared by the anionic copolymerization of 2-(trimethylsiloxy)ethyl methacrylate and MMA, followed by hydrolysis. The copolymer poly(HEMA-co-MMA) thus obtained possessed a hydroxyl group in each of its HEMA units. Another kind of vinyloxyl-containing (co)polymer was prepared by the anionic homopolymerization of 2-(vinyloxy)ethyl methacrylate (VEMA) or its copolymerization with MMA. The resulting (co)polymer possessed reactive vinyloxyl side groups. The copolymer networks were obtained by reacting each of the above-mentioned (co)polymers with a polyacetal prepared via the polyaddition between a divinyl ether and a diol. Three divinyl ethers (ethylene glycol divinyl ether, 1,4-butanediol divinyl ether, and 1,6-hexanediol divinyl ether) and three diols (ethylene glycol, 1,4-butanediol, and 1,6-hexanediol) were employed as monomers in the polyaddition step, and their combinations generated nine kinds of polyacetals. When a polyaddition reaction was terminated with a divinyl ether monomer, a polyacetal with two vinyloxyl end groups was obtained, which could further react with the hydroxyl groups of poly(HEMA-co-MMA) to generate a copolymer network. On the other hand, when a diol was used as terminator in the polyaddition, the resulting polyacetal possessed two hydroxyl end groups, which could react with the vinyloxyl groups of poly(VEMA) or poly(VEMA-co-MMA), to generate a copolymer network. All the copolymer networks exhibited degradation in the presence of acids. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 117–126, 2001

Light-induced polymerisation of photoinitiator-free vinyl ether/maleimide systems

The photo-induced copolymerisation of electron donor/electron acceptor monomers has been studied by real-time infrared spectroscopy. With stoichiometric maleimide-vinyl ether mixtures, the reaction was found to proceed within seconds upon UV exposure. For systems with an excess of vinyl ether, the two monomers disappeared at essentially the same rate, to generate an alternating copolymer. In such photoinitiator-free systems, the initiating radicals are mainly formed by hydrogen abstraction by the excited maleimide molecules. Highly crosslinked polymer networks have been obtained by light-induced copolymerisation of bismaleimide and divinyl ether monomers. One of the distinct characteristics of this type of radical-induced polymerisation, beside the absence of any added photoinitiator, is that it is less sensitive to oxygen inhibition than the conventional UV-curable acrylate resins.

Kinetic study of the photo-induced copolymerization of N-substituted maleimides with electron donor monomers

The photo-induced copolymerization of electron donor/electron acceptor monomers has been studied by real-time infrared spectroscopy. With maleimide/vinyl ether mixtures, the reaction was found to proceed rapidly upon u.v. exposure in the absence of oxygen to reach nearly 100% conversion within seconds. The two monomers disappeared at similar rates, with formation of an alternating copolymer. Similar results were obtained with maleimide/ N-vinylpyrrolidone and maleimide/styryloxy combinations. Highly crosslinked polymer networks have been produced by photo-induced copolymerization of bis-maleimide and divinyl ether monomers. These photoinitiator-free formulations were found to be less sensitive to oxygen inhibition than typical u.v.-curable acrylate resins. N-substituted maleimides were also shown to act as monomeric photoinitiators by inducing the polymerization of acrylate monomers upon u.v. irradiation.

Synthesis of silicon‐containing vinyl ether monomers and oligomers and their photoinitiated polymerization

Silicon-containing divinyl ether monomers were synthesized by the addition reaction of glycidyl vinyl ether (1) with various silyl dichlorides using tetra-n-butylammonium bromide (TBAB) as a catalyst. The reaction of 1 with diphenyl dichlorosilane gave bis-[1-(chloromethyl)-2-(vinyloxy)-ethyl]diphenyl silane (3a) in 89% yield. Polycondensations of 3a with terephthalic acid were also carried out using 1,8-Diazabicyclo[5.4.0]-7-undecene (DBU) to afford silicon-containing polyfunctional vinyl ether oligomers (5). A multifunctional Si-monomer with both vinyl ether and methacrylate groups (7) was prepared by the reaction of 3a with potassium methacrylate using TBAB as a phase transfer catalyst. Photoinitiated cationic polymerizations of these vinyl ether compounds proceeded rapidly using the sulfonium salt, bis-[4-(diphenyl-sulfonio)phenyl]sulfide-bis-hexafluorophoshate (DPSP), as the cationic photoinitiator in neat mixtures upon UV irradiation. Multifunctional monomer 7 with both vinyl ether and methacrylate groups showed “hybrid curing properties” using both DPSP and the radical photoinitiator, 2,4,6-trimethylbenzoyl diphenylphoshine oxide (TPO). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3217–3225, 1997

Synthesis of silicon-containing vinyl ether monomers and oligomers and their photoinitiated polymerization

Silicon-containing divinyl ether monomers were synthesized by the addition reaction of glycidyl vinyl ether (1) with various silyl dichlorides using tetra-n-butylammonium bromide (TBAB) as a catalyst. The reaction of 1 with diphenyl dichlorosilane gave bis-[1-(chloromethyl)-2-(vinyloxy)-ethyl]diphenyl silane (3a) in 89% yield. Polycondensations of 3a with terephthalic acid were also carried out using 1,8-Diazabicyclo[5.4.0]-7-undecene (DBU) to afford silicon-containing polyfunctional vinyl ether oligomers (5). A multifunctional Si-monomer with both vinyl ether and methacrylate groups (7) was prepared by the reaction of 3a with potassium methacrylate using TBAB as a phase transfer catalyst. Photoinitiated cationic polymerizations of these vinyl ether compounds proceeded rapidly using the sulfonium salt, bis-[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluorophoshate (DPSP), as the cationic photoinitiator in neat mixtures upon UV irradiation. Multifunctional monomer 7 with both vinyl ether and methacrylate groups showed hybrid curing properties using both DPSP and the radical photoinitiator, 2,4,6-trimethylbenzoyl diphenylphoshine oxide (TPO).

Photocrosslinking of functionalized rubber. III. Polymerization of multifunctional monomers in epoxidized liquid natural rubber

Different types of tridimensional polymer networks have been synthesized by photoinitiated polymerization of difunctional monomers blended to an epoxidized natural rubber. The crosslinking reaction was followed by infrared spectroscopy and shown to proceed extensively within less than 1 s for the cycloepoxy, vinyl ether, and acrylate monomers used. By acting as a plasticizer, the monomer was found to markedly accelerate the ring-opening polymerization of the epoxy groups of the rubber chain. Cationic polymerization continues to proceed effectively after the UV-exposure, until total consumption of the epoxy groups. The nature of the comonomer has a strong influence on the properties of the crosslinked rubber. Low-modulus polymers were obtained with divinyl ether monomers, while hard but still flexible films were obtained with dicycloepoxy and diacrylate monomers. © 1996 John Wiley & Sons, Inc.

An aqueous‐base developable photoresist based on light‐induced cationic polymerization: Resist performance of poly(glycidyl methacrylate‐co‐methacrylic acid)

AbstractAn aqueous‐base developable photoresist based on photoinduced cationic polymerization has been prepared by copolymerization of glycidyl methacrylate (GMA) and methacrylic acid (MAA). The copolymer containing 83 mol% of GMA unit is soluble in an aqueous base and crosslinked in the presence of photogenerated acid caused by acid‐initiated ring‐opening polymerization of pendant epoxide groups. Exposure results in the generation of acid and the subsequent baking process promotes the diffusion of photogenerated acid, which initiates the cationic crosslinking of the epoxide rings. It was also found that the sensitivity of the copolymer was remarkably enhanced when a divinyl ether monomer is added as a bifunctional crosslinker. The sensitivity enhancement may be caused by the high reactivity of the divinyl ether monomer in the presence of acid. The resist comprised of the copolymer, the vinyl ether monomer, and diphenyliodonium 9,10‐dimethoxy‐an‐thracene‐2‐sulfonate as photoacid generator exhibited the sensitivity of 20 mJ/cm2. A good pattern profile with high resolution was attained by exposure to a 365 nm light followed by a postexposure bake at 60°C for 3 min. © 1993 John Wiley & Sons, Inc.