Divinyl Ether Research Articles

Visible light‐induced thiol‐ene reaction: A new strategy to prepare Α,ω‐dithiol and Α,ω‐divinyl telechelic polythiolether oligomers

ABSTRACTA new strategy is developed to prepare both α,ω‐dithiol and α,ω‐divinyl linear telechelic polythiolether oligomers by visible light induced thiol‐ene chemistry in the presence of a fac‐Ir(ppy)3 photoredox catalyst. Polythiolether oligomers of well‐defined end groups and controlled molecular weights have been successfully synthesized at varying monomer molar ratios of 1,4‐benzenedimethanethiol (BDMT) to diethylene glycol divinyl ether (DEGVE). 1H NMR and MALDI‐TOF MS analyses demonstrate that as‐prepared polythiolethers possess high end‐group fidelity, which is further supported by the successful polyaddition of polythiolethers bearing α,ω‐dithiol and α,ω‐divinyl groups. For example, with the α,ω‐dithiol‐ (Mn = 1900 g mol−1, PDI = 1.25) and α,ω‐divinyl‐terminated (Mn = 2000 g mol−1, PDI = 1.29) polythiolethers as macromonomers, the molecular weight of resulting polythiolether is up to 7700 g mol−1 with PDI as 1.67. The reactivity of the terminal thiol group is further confirmed by the addition reaction with N‐(1‐pyrenyl)maleimide. UV‐vis spectra and fluorescene measurements suggest that fac‐Ir(ppy)3 undergo a redox quenching process reacted with BDMT to generate thiyl free radicals. With these results, the mechanism of the thiol‐ene reaction catalyzed by photoredox catalyst is proposed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 740–749

Unprecedented reactions: from epichlorohydrin to epoxyglycidyl substituted divinyl ether and its conversion into epoxyglycidyl propargyl ether.

The reaction of epichlorohydrin with concentrated sodium hydroxide in hexane under phase transfer conditions has surprisingly led to the formation of the symmetrical di(3-epoxyglycidyl-1-propenyl) ether 1 which contains both nucleophilic and electrophilic moieties. When it was reacted with n-butyllithium, intermediate 1 once again surprisingly generated epoxyglycidyl propargyl ether, which was further reacted in situ with a variety of benzaldehydes to furnish the corresponding substituted propargylic alcohols in good yields. While the reaction is operationally simple, it provides a powerful method for the synthesis of the important products from commodity materials such as epichlorohydrin. Moreover, these reactions may have revealed that some fundamental properties of the hydroxide anion in those once thought straightforward reactions are not well understood. A careful analysis of the experimental data suggests that an unprecedented concerted elimination of the epoxyglycidyl ether with sodium hydroxide may be operative and an alpha deprotonation followed by alpha elimination of the di(3-epoxyglycidyl-1-propenyl) ether with alkyllithium may have been involved.

Oxylipins in the spikemoss Selaginella martensii: Detection of divinyl ethers, 12-oxophytodienoic acid and related cyclopentenones

Green tissues of spikemoss Selaginella martensii Spring possessed the complex oxylipins patterns. Major oxylipins were the products of linoleic and α-linolenic acids metabolism via the sequential action of 13-lipoxygenase and divinyl ether synthase (DES) or allene oxide synthase (AOS). AOS products were represented by 12-oxophytodienoic acid (12-oxo-PDA) isomers. Exceptionally, S. martensii possesses high level of 12-oxo-9(13),15-PDA, which is very uncommon in flowering plants. Separate divinyl ethers were purified after micro-preparative incubations of linoleic or α-linolenic acids with homogenate of S. martensii aerial parts. The NMR data allowed us to identify all geometric isomers of divinyl ethers. Linoleic acid was converted to divinyl ethers etheroleic acid, (11Z)-etheroleic acid and a minority of (ω5Z)-etheroleic acid. With α-linolenate precursor, the specificity of divinyl ether biosynthesis was distinct. Etherolenic and (ω5Z)-etherolenic acids were the prevailing products while (11Z)-etherolenic acid was a minor one. Divinyl ethers are detected first time in non-flowering land plant. These are the first observations of fatty acid metabolism through the lipoxygenase pathway in spikemosses (Lycopodiophyta).

N-Vinylcarbazole as Versatile Photoinaddimer of Photopolymerization under Household UV LED Bulb (392 nm).

N-vinylcarbazole (NVK) can act simultaneously as a photoinitiator, an additive, and a mono-mer (photoinaddimer) of photopolymerization upon exposure to the household ultraviolet (UV) light-emitting diode (LED) bulb (emission wavelength centered at 392 nm). Even though the light absorption spectrum of NVK exhibits weak overlapping with the emission spectrum of the UV LED, the active species (i.e., radicals and cations) can be generated from the interaction between NVK and diphenyliodonium hexafluorophosphate (Iod) under irradiation of this LED device, which is investigated by steady state photolysis and electron spin resonance spin-trapping methods. Interestingly, the generated radicals and cations from the NVK/Iod system demonstrate high efficiency to initiate the free radical photopolymerization of (meth)acrylates and the cationic photopolymerization of epoxide and divinyl ether under the UV LED irradiation, and the one-step simultaneous catonic/radical photopolymerization of expoxide/acrylate blend can lead to the formation of tack free polyacrylate/polyether-based interpenetrated polymer network film within 10 min even when the polymerization process is exposed to the atmosphere highlighting the high efficiency of the system to reduce the oxygen inhibition effect. More interestingly, NVK/Iod system can also initiate the photopolymerization of NVK under the UV LED irradiation to produce polyvinylcarbazole, and NVK acts as both a photoinitiator and a monomer in the system.

An in situ intercalative polymerization method for preparing UV curable clay–polymer nanocomposites

ABSTRACTA novel in situ intercalative polymerization technique was used to disperse clay mineral in a precursor resin for use in UV curing by performing an in situ ion exchange reaction during polyesterification. Unmodified montmorillonite (MMT) was added to a reaction mixture composed of monomers and methyl, tallow, bis‐2‐hydroxyethyl ammonium (MTEtOH) during the synthesis of unsaturated polyesters to create resins containing highly dispersed, organically modified MMT. UV‐curable clay–polymer nanocomposite (CPN) films were then prepared utilizing donor–acceptor chemistry through reactions of the unsaturated polyester resin with triethylene glycol divinyl ether. Functional group conversion improved up to 15% by the incorporation of clay mineral into the polymer matrix through the in situ polymerization method. The CPNs also had improved barrier, mechanical, and thermal properties over a control film containing no clay mineral. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42601.

Biochemical characterization of allene oxide synthases from the liverwort Marchantia polymorpha and green microalgae Klebsormidium flaccidum provides insight into the evolutionary divergence of the plant CYP74 family.

Allene oxide synthases (AOSs) were isolated from liverworts and charophytes. These AOSs exhibited enzymatic properties similar to those of angiosperms but formed a distinct phylogenetic clade. Allene oxide synthase (AOS) and hydroperoxide lyase (HPL) mediate the formation of precursors of jasmonates and carbon-six volatiles, respectively. AOS and HPL utilize fatty acid hydroperoxides and belong to the plant cytochrome P450 74 (CYP74) family that mediates plant defense against herbivores, pathogens, or abiotic stresses. Although members of the CYP74 family have been reported in mosses and other species, the evolution and function of multiple CYP74 genes in plants remain elusive. Here, we show that the liverwort Marchantia polymorpha belongs to a basal group in the evolution of land plants; has two closely related proteins (59% identity), MpAOS1 and MpAOS2, that are similar to moss PpAOS1 (49 and 47% identity, respectively); and exhibits AOS activity but not HPL activity. We also found that the green microalgae Klebsormidium flaccidum, consist of multicellular and non-branching filaments, contains an enzyme, KfAOS, that is similar to PpAOS1 (37% identity), and converts 13-hydroperoxide of linolenic acid to 12-oxo-phytodienoic acid in a coupled reaction with allene oxide cyclase. Phylogenetic analysis showed two evolutionarily distinct clusters. One cluster comprised AOS and HPL from charophytic algae, liverworts, and mosses, including MpAOSs and KfAOS. The other cluster was formed by angiosperm CYP74. Our results suggest that plant CYP74 enzymes with AOS, HPL, and divinyl ether synthase activities have arisen multiple times and in the two different clades, which occurred prior to the divergence of the flowering plant lineage.

Preparation of 2‐(dimethylamino) ethyl methacrylate copolymer micelles for shape memory materials

ABSTRACTResearchers are actively developing shape memory polymers (SMPs) for smart biomaterials. This paper reports a new SMP system synthesized from biocompatible 2‐(dimethylamino) ethyl methacrylate (DMAEMA), butyl acrylate (BA) and tri(ethylene glycol) divinyl ether (TDE). Preliminary results show that the DMAEMA‐co‐BA‐co‐TDE copolymers form micelles in aqueous solution due to chemical crosslinking and hydrophobicity. The micelle size decreased with the increase in the BA content since the hydrophobicity of copolymers increases with the increase of BA content. The resulting polymer films contain–N(CH3)2 functional groups for further biomaterial applications. The thermal stability of DMAEMA‐co‐BA‐co‐TDE copolymers is determined by the DMAEMA structure and content. Moreover, the copolymers form micro‐phase‐separated structures containing a reversible amorphous soft phase, and the storage moduli decreases significantly around Tg. Therefore, good thermal‐induced shape memory effects are achieved in the DMAEMA‐co‐BA‐co‐TDE copolymers by adjusting the BA content. This work proposes a new strategy for designing smart biomaterials using a biocompatible monomer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42312.

Star-shaped cyclopolymers: A new category of star polymer with rigid cyclized arms prepared by controlled cationic cyclopolymerization and subsequent microgel formation of divinyl ethers

The combination of living/controlled cationic cyclopolymerization and crosslinking polymerization of bifunctional vinyl ethers (divinyl ethers) was applied to the synthesis of core-crosslinked star-shaped polymers with rigid cyclized arms. Cyclopolymerization of 4,4-bis(vinyloxymethyl)cyclohexene (1), a divinyl ether with a cyclohexene group, was investigated with the hydrogen chloride/zinc chloride (HCl/ZnCl2) initiating system in toluene at 0 °C. The reaction proceeded quantitatively to give soluble poly(1)s in organic solvents. The content of the unreacted vinyl groups in the produced polymers was less than ∼3 mol%, and therefore, the degree of cyclization of the polymers was determined to be ∼97%. The number-average molecular weight (Mn) of the polymers increased in direct proportion to monomer conversion and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture, indicating that living cyclopolymerization of 1 occurred. The chain linking reactions among the formed living cyclopolymers with 1,4-bis(vinyloxy)cyclohexane (3) as a crosslinker in toluene at 0 °C produced core-crosslinked star-shaped cyclopoly(1)s [star-poly(1)s] in high yield (100%). Dihydroxylation of the cyclohexene double bonds of star-poly(1) gave hydrophilic water-soluble star-shaped polymers with rigid arm structure [star-poly(1)-OH] with thermo-responsive function in water. Tgs of star-poly(1) and star-poly(1)-OH were 135 °C and 216 °C, respectively; these values are very high as vinyl ether-based star-shaped polymers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1094–1102

Synthesise of Polythioether and Heat Resistant Property of Polythioether Sealants

Polythioether sealants are considered as new generational aeronautical sealants. First, by changing molecular structure, the feasibility of forming certain molecular weight of polythioethers was studied. Experiment show that most terminal dienes can react with dithiol generating certain molecular polythioethers. Then, analysis show that the linear polythioethers owning high degree of molecular regularity usually have rather low glass transition temperature (Tg), below -50oC, however, those polythioethers are very easily to crystalize. If they are not liquid at room temperature they can be used as raw rubber. If main chain of polythioether contains benzene ring, 5% weight loss temperatures will be improved, however, Tg will increase a lot, which cannot allow them to be used at low temperature. At last, using those polythioethers which are liquid at room temperature as raw rubber and Manganese Dioxide (MnO2) as curing agent, prepare kinds of sealants. The result shows that polythioether sealant prepared by reaction product of 1,6-Hexanedithiol and diethylene glycol divinyl ether(DGDE) has the highest tensile strength, which is 5.84MPa. After hot air aging (at 160oC and 100h), the sealant employing the polythioether synthesized by 2,2’-oxydiethanethiol and DGDE has the best thermal stability, the tensile strength only decrease 28%.

Study of Ink‐Jet Printable Vinyl Ether‐Graphene UV‐Curable Formulations

AbstractThis work reports the formulation of vinyl ether containing functionalized graphene sheets in order to produce UV‐curable conductive inks. The best graphene‐surfactant ratio was found to give a stable dispersion of graphene into triethyleneglycol divinyl ether (DVE3) resin, avoiding the presence of large filler aggregates that could clog printing head during ink‐jet process. Propylene carbonate was used as solvent to adjust the viscosity of the formulation. The presence of graphene did not significantly hindered the UV‐curing process. Crosslinked nanocomposite materials show a decrease of resistivity of seven order of magnitude with respect to the pristine polymeric matrix.

EB-crosslinked SPEEK electrolyte membrane with 1,4-butanediol divinyl ether/triallyl isocyanurate for fuel cell application

In this study, crosslinked sulfonated poly(ether ether ketone) (SPEEK) membranes were prepared using an EB-irradiation crosslinking method with various contents of a crosslinker mixture (1,4-butanediol divinyl ether (BDVE)/triallyl isocyanurate (TAIC), 9/1 wt. ratio) and applied as a proton exchange membrane (PEM) for fuel cell application. It was found that the degree of crosslinking of the EB-crosslinked SPEEK membranes was increased with an increase in the BDVE/TAIC crosslinker content from gel fraction results. The chemical stability was also found to be improved with an increase in the content of the crosslinker mixture. The water uptake, IEC, and proton conductivity of the crosslinked membrane was found to be decreased with an increase in the BDVE/TAIC crosslinker content. The DMA and SAXS data indicated that the EB-crosslinked SPEEK membrane have well-developed ionic aggregation in the cluster regions. In addition, the current density of the crosslinked membranes was measured to be higher than 1198mA/cm2 at a 0.4 voltage (V) under fully hydrated conditions at 80°C with a 1.5bar backpressure from a MEA cell performance test.

Autoxidation as a trigger for the slow release of volatile perfumery chemicals

ABSTRACTFinding suitable precursor molecules that extend the lifetime of perfumes by decomposing and releasing fragrant chemicals under relatively mild, ambient conditions remains a significant challenge. Although the majority of effort in this regard has been directed toward using hydrolysis reactions as the release event, autoxidation and subsequent fragmentation reactions also would appear to be well suited for this purpose given the constant exposure of deposited perfumes to atmospheric oxygen. Divinyl ethers, prepared from enolizable perfume aldehydes, have two olefin functions adjacent to the ether oxygen and were found to provide prolonged release of fragrant carbonyl compounds by an autoxidative fragmentation process. After deposition onto cotton terry cloth from a liquid fabric softener, dynamic headspace analysis showed the liberation of the parent aldehyde along with a one‐carbon smaller carbonyl compound and the enol formate ester of the parent aldehyde. Depending on the structure of the divinyl ether both liberated carbonyl compounds can be perfumery materials and both always were released from the cotton at significantly higher levels than the unmodified parent aldehydes used to prepare reference samples. Autoxidation of the divinyl ethers initiated by peroxy‐radical addition to alkene functions would account for the oxidative cleavage reactions yielding the smaller carbonyl compounds and the enol formates. Hydrolysis of the enol formate could generate the parent aldehyde. The liberation of volatile carbonyl compounds from divinyl ethers demonstrates the potential usefulness of autoxidation as a trigger for the sustained release of fragrant compounds from suitably designed precursors. Copyright © 2014 John Wiley & Sons, Ltd.

Surface modification of PDMS microchips with poly(ethylene glycol) derivatives for μTAS applications

In this work is presented a method for the modification of native PDMS surface in order to improve its applicability as a substrate for microfluidic devices, especially in the analysis of nonpolar analytes. Therefore, poly(ethylene glycol) divinyl ether modified PDMS substrate was obtained by surface modification of native PDMS. The modified substrate was characterized by attenuated total reflectance infrared spectroscopy, water contact angle measurements, and by evaluating the adsorption of rhodamine B and the magnitude of the EOF mobility. The reaction was confirmed by the spectroscopic evaluation. The formation of a well-spread water film over the surface immediately after the modification was an indicative of the modified surface hydrophilicity. This characteristic was maintained for approximately ten days, with a gradual return to a hydrophobic state. Fluorescence assays showed that the nonpolar adsorption property of PDMS was significantly decreased. The EOF mobility obtained was 3.6 × 10(-4) cm(2) V(-1) s(-1) , higher than the typical values found for native PDMS. Due to the better wettability promoted by the modification, the filling of the microchannels with aqueous solutions was facilitated and trapping of air bubbles was not observed.

Detection and molecular cloning of CYP74Q1 gene: Identification of Ranunculus acris leaf divinyl ether synthase

Enzymes of the CYP74 family, including the divinyl ether synthase (DES), play important roles in plant cell signalling and defence. The potent DES activities have been detected before in the leaves of the meadow buttercup (Ranunculus acris L.) and few other Ranunculaceae species. The nature of these DESs and their genes remained unrevealed. The PCR with degenerate primers enabled to detect the transcript of unknown P450 gene assigned as CYP74Q1. Besides, two more CYP74Q1 isoforms with minimal sequence variations have been found. The full length recombinant CYP74Q1 protein was expressed in Escherichia coli. The preferred substrates of this enzyme are the 13-hydroperoxides of α-linolenic and linoleic acids, which are converted to the divinyl ether oxylipins (ω5Z)-etherolenic acid, (9Z,11E)-12-[(1′Z,3′Z)-hexadienyloxy]-9,11-dodecadienoic acid, and (ω5Z)-etheroleic acid, (9Z,11E)-12-[(1′Z)-hexenyloxy]-9,11-dodecadienoic acid, respectively, as revealed by the data of mass spectrometry, NMR and UV spectroscopy. Thus, CYP74Q1 protein was identified as the R. acris DES (RaDES), a novel DES type and the opening member of new CYP74Q subfamily.

Oxylipins and plant abiotic stress resistance.

Oxylipins are signaling molecules formed enzymatically or spontaneously from unsaturated fatty acids in all aerobic organisms. Oxylipins regulate growth, development, and responses to environmental stimuli of organisms. The oxylipin biosynthesis pathway in plants includes a few parallel branches named after first enzyme of the corresponding branch as allene oxide synthase, hydroperoxide lyase, divinyl ether synthase, peroxygenase, epoxy alcohol synthase, and others in which various biologically active metabolites are produced. Oxylipins can be formed non-enzymatically as a result of oxygenation of fatty acids by free radicals and reactive oxygen species. Spontaneously formed oxylipins are called phytoprostanes. The role of oxylipins in biotic stress responses has been described in many published works. The role of oxylipins in plant adaptation to abiotic stress conditions is less studied; there is also obvious lack of available data compilation and analysis in this area of research. In this work we analyze data on oxylipins functions in plant adaptation to abiotic stress conditions, such as wounding, suboptimal light and temperature, dehydration and osmotic stress, and effects of ozone and heavy metals. Modern research articles elucidating the molecular mechanisms of oxylipins action by the methods of biochemistry, molecular biology, and genetics are reviewed here. Data on the role of oxylipins in stress signal transduction, stress-inducible gene expression regulation, and interaction of these metabolites with other signal transduction pathways in cells are described. In this review the general oxylipin-mediated mechanisms that help plants to adjust to a broad spectrum of stress factors are considered, followed by analysis of more specific responses regulated by oxylipins only under certain stress conditions. New approaches to improvement of plant resistance to abiotic stresses based on the induction of oxylipin-mediated processes are discussed.

Application of a carbazole derivative as a spectroscopic fluorescent probe for real time monitoring of cationic photopolymerization

Abstract The performance of 1-(9-ethylcarbazol-3-yl)-4,4,4-trifluorobutane-1,3-dione (1) as a fluorescent probe for the monitoring of cationic photopolymerization processes by Fluorescence Probe Technique (FPT) has been evaluated in comparison with the response of 7-diethylamino-4-methylcoumarin (Coumarin 1) (2). Triethylene glycol divinyl ether and diphenyliodonium hexafluorophosphate were used as an example monomer and a cationic photoinitiator respectively. It has been found that the probe 1 withstands the cationic polymerization conditions and provides correct probe response. 1-(9-ethylcarbazol-3-yl)-4,4,4-trifluorobutane-1,3-dione shifts its fluorescence spectrum with progress of cationic photopolymerization of the monomer, which enables the monitoring of the polymerization progress using the fluorescence intensity ratio measured at two different wavelengths as the progress indicator. By comparing the behavior of 1 and 2, it has been documented that the fluorescence spectrum of probe 1 shows a spectacular hypsochromic shift (Δλ = 33 nm) upon the monomer polymerization, while the shift of 2 is three times smaller (Δλ = 11 nm). Moreover, the sensitivity of probe 1 is more than 2.5-times higher than that of any other probes suitable for monitoring cationic polymerization processes, reported previously. Therefore, application of the carbazole derivative (1) as a new probe for the monitoring of the crosslinking process of coatings cured by cationic photopolymerization has been proposed.

Green light sensitive diketopyrrolopyrrole derivatives used in versatile photoinitiating systems for photopolymerizations

The monomeric (DPPDT) and polymeric (PDQT) diketopyrrolopyrrole–thiophene derivatives combined with an iodonium salt or an amine (and optionally an additive) are used as photoinitiating systems to initiate the cationic polymerization of epoxides or divinyl ethers, radical polymerization of acrylates and thiol–ene polymerization under different irradiation sources (i.e. very soft halogen lamp, laser diodes at 473 nm, 532 nm and 808 nm). The DPPDT based systems are very efficient upon the green light exposure. Remarkably, these systems are characterized by a higher efficiency than references based on camphorquinone, a well known photosensitizer for visible light. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis and electron spin resonance spin trapping techniques.

Isolation and structure elucidation of linolipins C and D, complex oxylipins from flax leaves

Two complex oxylipins (linolipins C and D) were isolated from the leaves of flax plants inoculated with phytopathogenic bacteria Pectobacterium atrosepticum. Their structures were elucidated based on UV, MS and NMR spectroscopic data. Both oxylipins were identified as digalactosyldiacylglycerol (DGDG) molecular species. Linolipin C contains one residue of divinyl ether (ω5Z)-etherolenic acid and one α-linolenate residue at sn-1 and sn-2 positions, respectively. Linolipin D possesses two (ω5Z)-etherolenic acid residues at both sn-1 and sn-2 positions. The rapid formation (2-30min) of linolipins C and D alongside with linolipins A and B occurred in the flax leaves upon their damage by freezing-thawing.

Alteration of the catalytic properties of divinyl ether synthase as a result of substitutions of unique amino acids

Alteration of the catalytic properties of divinyl ether synthase as a result of substitutions of unique amino acids

Synthesis and Properties of Hybrid Curing Siloxane Modified Epoxy Resin/Polyurethane Acrylate Coating

In order increasing properties of polyurethane acrylate coating, the epoxy resin/ polyurethane acrylate coating was prepared by UV and thermal dual curing with diphenyliodonium salt. The curing reaction and kinetics was investigated by UV-radiation and DSC, and the influence of the siloxane of methylacryloylpropyl-trimethoxysilane (MAPTMS) content on the properties of coating was determined by DMA and other physical methods. The results showed the hardness and glass transition temperature Tg of the coating film increased with the increasing MAPTMS content and the coating has good adhesion. When the content of MAPTMS reach 12 wt%, the Tg is the highest, which is 8.2°C higher than the before; When the triethylene glycol divinyl ether (DVE-3) can change the reaction from UV free radical/cationic reaction into thermal radical/cationic reaction, and can be described by autocatalytic Šesták-Berggre model (S-B) and the average activation energy Ea is 70.55 kJ/mol.