scholarly journals New BODIPY Dyes Based on Benzoxazole as Photosensitizers in Radical Polymerization of Acrylate Monomers

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 662
Author(s):  
Agnieszka Skotnicka ◽  
Janina Kabatc
Keyword(s):  
Radical Polymerization ◽  
Fluorescence Quantum Yield ◽  
Phenyl Ring ◽  
High Performance ◽  
Chemical Structure ◽  
Pyridinium Salt ◽  
Mercury Lamp ◽  
Acrylate Monomer ◽  
Iodonium Salt ◽  
Acrylate Monomers

A series of 2-phenacylbenzoxazole difluoroboranes named BODIPY dyes (1–8) was designed and applied as photosensitizers (PS) for radical photopolymerization of acrylate monomer. The light absorption within the ultraviolet-visible (UV–Vis) range (λmax = 350–410 nm; εmax = 23,000–42,500 M−1cm−1), that is strongly influenced by the substituents on the C3 and C4 atoms of phenyl ring, matched the emission of the Omnicure S2000 light within 320–500 nm. The photosensitizer possess fluorescence quantum yield from about 0.005 to 0.99. The 2-phenacylbenzoxazole difluoroboranes, together with borate salt (Bor), iodonium salt (Iod) or pyridinium salt (Pyr) acting as co-initiators, can generate active radicals upon the irradiation with a High Pressure Mercury Lamp which initiates a high-performance UV–Vis light-induced radical polymerization at 320–500 nm. The polymers obtained are characterized by strong photoluminescence. It was found that the type of radical generator (co-initiator) has a significant effect on the kinetic of radical polymerization of acrylate monomer. Moreover, the chemical structure of the BODIPY dyes does not influence the photoinitiating ability of the photoinitiator. The concentration of the photoinitiating system affects the photoinitiating performance. These 2-phenacylbenzoxazole difluoroborane-based photoinitiating systems have promising applications in UV–Vis-light induced polymerization.

Curing behaviour and mechanical properties of pigmented UV-curable epoxy acrylate coatings

2014 ◽  
Vol 43 (4) ◽  
pp. 177-184 ◽  
Author(s):  
Pooneh Kardar ◽  
Morteza Ebrahimi ◽  
Saeed Bastani
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Chemical Structure ◽  
Epoxy Acrylate ◽  
Acrylate Monomer ◽  
Uv Curable ◽  
Content Type ◽  
Reactive Diluents ◽  
Acrylate Monomers ◽  
And Storage

Purpose – The purpose of this work was to study the effect of chemical structure of reactive diluents on the curing behaviour and physical–mechanical properties of a titanium dioxide pigmented UV-curable epoxy acrylate system. Design/methodology/approach – Two different tri-functional and two different tetra-functional acrylate monomers were used as reactive diluents in the formulations. The curing behaviour of the formulations was studied by using photo-differential scanning calorimetry analysis. The rate of curing, conversion at the maximum rate and ultimate conversion for different formulations were calculated. In addition, the physical and mechanical characteristics of the cured films, including glass transition temperature and modulus, were measured by using a dynamic mechanical analysis technique. Findings – The results showed that the ultimate conversion for non-pigmented pentaerythritol triacrylate (PETA) and trimethylol propane triacrylate (TMPTA) formulations were almost similar, but the interference effect of titanium dioxide particles on the curing of the PETA formulations was found to be more considerable in comparison to the TMPTA formulations. The extent of reaction for tetra-functional acrylate monomers was considerably less than those for tri-functional acrylate monomers. The Tg and storage modulus of non-pigmented PETA, TMPTA and pentaerythritol tetraacrylate (PE4TA) formulations were almost the same and higher than that for ditrimethylol propane tetraacrylate (DiTMP4TA) formulations. However, Tg and storage modulus of pigmented tetra-functional acrylate monomer formulations were higher than those for tri-acrylate monomer formulations. Research limitations/implications – The curing conditions (temperature and UV intensity) can affect the network formation and consequently will affect on the properties of the cured films. Practical implications – The pigmented UV-curable coatings are interested for many industries such as wood and automotive industries. The reported data can be used by the formulators working in the R&D departments. In addition, the results obtained can be used by the researchers who are active in the field of structure–property relationship for UV-curable coatings. Social implications – UV-curing systems are considered as one of the most environment-friendly coatings system. Therefore, the developing of its knowledge can help to extend its usage to different applications. Originality/value – The photopolymerisation of pigmented coatings is a great challenge and is hardly investigated in the literature. Therefore, in this research, the effect of chemical structure and functionality of different multifunctional acrylate monomers on the curing behaviour of pigmented formulations was investigated.

scholarly journals Cubane Cu4I4(phosphine)4 Complexes as New Co-initiator for Free Radical Photopolymerization: Towards Aromatic Amine-Free Systems

2021 ◽  
Author(s):  
Jacques Lalevée ◽  
Fatima Hammoud ◽  
Mahmoud Rahal ◽  
Julien Egly ◽  
Fabrice Morlet-Savary ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Aromatic Amine ◽  
Free Radical Polymerization ◽  
Copper Iodide ◽  
Free Radical Photopolymerization ◽  
Acrylate Monomers ◽  
First Time

The investigation of copper-iodide cubane derivatives as new co-initiators for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions is described for the first time here. These...

scholarly journals Panchromatic Copper Complexes for Visible Light Photopolymerization

Photochem ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 167-189
Author(s):  
Alexandre Mau ◽  
Guillaume Noirbent ◽  
Céline Dietlin ◽  
Bernadette Graff ◽  
Didier Gigmes ◽  
...  
Keyword(s):  
Free Radical ◽  
Visible Light ◽  
Radical Polymerization ◽  
Copper Complexes ◽  
Free Radical Polymerization ◽  
Photoluminescence Properties ◽  
System Formation ◽  
Iodonium Salt ◽  
Visible Light Photopolymerization ◽  
Cationic Polymerizations

In this work, eleven heteroleptic copper complexes were designed and studied as photoinitiators of polymerization in three-component photoinitiating systems in combination with an iodonium salt and an amine. Notably, ten of them exhibited panchromatic behavior and could be used for long wavelengths. Ferrocene-free copper complexes were capable of efficiently initiating both the radical and cationic polymerizations and exhibited similar performances to that of the benchmark G1 system. Formation of acrylate/epoxy IPNs was also successfully performed even upon irradiation at 455 nm or at 530 nm. Interestingly, all copper complexes containing the 1,1′-bis(diphenylphosphino)ferrocene ligand were not photoluminescent, evidencing that ferrocene could efficiently quench the photoluminescence properties of copper complexes. Besides, these ferrocene-based complexes were capable of efficiently initiating free radical polymerization processes. The ferrocene moiety introduced in the different copper complexes affected neither their panchromatic behaviors nor their abilities to initiate free radical polymerizations.

scholarly journals Synthesis of poly (n-butyl acrylate) with tempo by nitroxide mediated polymerization method

2021 ◽  
pp. 096739112110245
Author(s):  
Amrita Sharma ◽  
PP Pande
Keyword(s):  
Butyl Acrylate ◽  
Low Cost ◽  
Polymerization Process ◽  
Polymerization Reaction ◽  
High Concentration ◽  
Acrylate Monomer ◽  
Controlled Polymerization ◽  
Acrylate Monomers ◽  
Nitroxide Mediated Polymerization ◽  
Polymerization Method

It has been observed that acrylate monomers are very difficult to polymerize with the low cost nitroxide catalyst 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO). Therefore, costly acyclic nitroxides such as N-tert-butyl-N-(1-diethylphosphono-2,2-dimethyl)-N-oxyl, (SG1), 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) and TIPNO derivatives have to be used for the polymerization of the acrylic acid derivatives. There are very few reports on the use of TEMPO-derivatives toward the polymerization of n-butyl acrylate. Generally different reducing agents viz. glucose, ascorbic acid, hydroxyacetone etc. have been used to destroy excess TEMPO during the polymerization reaction. The acrylate polymerizations fail in the presence of TEMPO due to the strong C–O bond formed between the acrylate chain end and nitroxide. To the best of our knowledge, no literature report is available on the use of TEMPO without reducing agent or high temperature initiators, toward the polymerization of n-butyl acrylate. The present study has been carried out with a view to re-examine the application of low cost nitroxide TEMPO, so that it can be utilized towards the polymerization of acrylate monomers (e.g. n-butyl acrylate). We have been able to polymerize n-butyl acrylate using the nitroxide TEMPO as initiator (via a macroinitiator). In this synthesis, a polystyrene macroinitiator was synthesized in the first step from TEMPO, after this TEMPO end-capped styrene macroinitiator (PSt-TEMPO) is used to polymerize n-butyl acrylate monomer. The amount of macroinitiator taken was varied from 0.05% to 50% by weight of n-butyl acrylate monomer. The polymerization was carried out at 120°C by bulk polymerization method. The experimental findings showed a gradual increase in molecular weight of the polymer formed and decrease in the polydispersity index (PDI) with increase in amount of PSt-TEMPO macroinitiator taken. In all experiments conversion was more than 80%. These results indicate that the polymerization takes place through controlled polymerization process. Effect of different solvents on polymerization has also been investigated. In the following experiments TEMPO capped styrene has been used as macroinitiator leading to the successful synthesis of poly n-Butyl acrylate. It has been found that styrene macroinitiator is highly efficient for the nitroxide mediated polymerization, even in very small concentration for the synthesis of poly n-butyl acrylate. High concentration of macroinitiator results in the formation of block copolymers of polystyrene and poly ( n-butyl acrylate) viz. polystyrene-block-poly-( n-butyl acrylate). The use of TEMPO toward controlled polymerization is of much importance, because it is the nitroxide commercially available at the lowest cost.

Direct Growth of Polyaniline Chains from Nitrogen Site of N-Doped Carbon Nanotubes for High Performance Supercapacitor

2014 ◽  
Vol 93 ◽  
pp. 164-167 ◽  
Author(s):  
Joon Won Lim ◽  
Atta Ul Haq ◽  
Sang Ouk Kim
Keyword(s):  
Carbon Nanotubes ◽  
High Performance ◽  
Chemical Structure ◽  
Carbon Materials ◽  
Graphitic Carbon ◽  
Polymer Grafting ◽  
Aniline Monomer ◽  
Defect Site ◽  
Direct Growth ◽  
Grafting From

Polymer grafting from graphitic carbon materials has been explored for several decades. Currently existing methods mostly employ harsh chemical treatment to generate defect site in graphitic carbon plane, which are used as active site for polymerization of precursors. Unfortunately, the treatment cause serious degradation of chemical structure and material properties. Here, we present a straightforward route for growth of polyaniline chain from nitrogen (N)-sites of carbon nanotubes. N site in the CNT wall initiates the polymerization of aniline monomer, which generates seamless hybrids composed of polyaniline directly grafted onto the CNT walls. The synthesized hybrids show excellent synergistic electrochemical performance, and are employed for electrodes of pseudo-capacitor. This approach offers an efficient way to obtain hybrid system consisting of conducting polymers directly grafted from graphitic dopant sites.

Cytokinin activity of some substituted ureas and thioureas

1966 ◽  
Vol 165 (999) ◽  
pp. 245-265 ◽  
Keyword(s):  
Biological Activity ◽  
Active Compound ◽  
Phenyl Ring ◽  
Chemical Structure ◽  
Lower Activity ◽  
Cytokinin Activity ◽  
Hydrogen Atoms ◽  
Detectable Activity ◽  
Low Activity

N , N '-Diphenylurea was shown to have reproducible cytokinin activity . Some 500 ureas, mainly of the N -monosubstituted and N , N '-disubstituted types, were tested an d about one half of these were active. Attempts were made to correlate chemical structure with biological activity. Although there are some exceptions to nearly every generalization it has been possible to formulate some principles. (1) Phenyl urea was the simplest active compound. (2) An HNCONH bridge conferred higher activity than an HNCSNH linkage and any other tested arrangement of the bridge gave inactive com pounds. (3) Compounds in which both amino hydrogen atoms on one or both sides of the bridge were substituted were of low activity or were inactive. (4) Many com pounds of the type R NHCONH 2 in which R = a substituted phenyl ring were tested. Ring substitution generally increased the activity and the highest activity was associated with meta substitution and the lowest with ortho . Compounds with electron-attracting substituents were generally more active than those with electron-donating substituents. Pyridyl compounds were active but com pounds with non-planar rings were inactive. (5) In compounds of the type R NHCONH R ' in which R and R ' were phenyl or substituted phenyl groups the highest activities were usually found in com pounds with one unsubstituted phenyl ring. Those with two substituted phenyl groups generally had lower activity. Some ureas showed detectable activity at 0.1 parts/10 6 . This was about four times less active than kinetin when tested in the tobacco pith assay.

A novel naphthalimide scaffold based iodonium salt as a one-component photoacid/photoinitiator for cationic and radical polymerization under LED exposure

2016 ◽  
Vol 7 (37) ◽  
pp. 5873-5879 ◽  
Author(s):  
N. Zivic ◽  
M. Bouzrati-Zerrelli ◽  
S. Villotte ◽  
F. Morlet-Savary ◽  
C. Dietlin ◽  
...  
Keyword(s):  
Radical Polymerization ◽  
Cationic Polymerization ◽  
Iodonium Salt

A strong drawback to overcome for photoinitiators of cationic polymerization or photoacids is their low photosensitivity for long wavelengths.

scholarly journals METHYL 10-EPI-PHEOPHORBIDE A FROM MCF-7 CELLS ACTIVE LAYER OF THE INDONESIAN FICUS DELTOIDEA JACK LEAVES

2017 ◽  
Vol 9 (8) ◽  
pp. 183 ◽  
Author(s):  
Anggia Murni ◽  
Novriyandi Hanif ◽  
Masaki Kita ◽  
Latifah K. Darusman
Keyword(s):  
Active Layer ◽  
Column Chromatography ◽  
Breast Tumor ◽  
High Performance ◽  
Chemical Structure ◽  
High Resolution Mass Spectrometry ◽  
Assay Method ◽  
Pheophorbide A ◽  
Ficus Deltoidea ◽  
Mcf 7

Objective: To isolate and elucidate a cytotoxic principle against breast tumor MCF-7 cells of the Indonesian terrestrial plant Ficus deltoidea Jack leaves.Methods: F. deltoidea leaves collected at National Park of mount Gede-Pangrango, Indonesia have been subjected to chemical and biological work. F. deltoidea leaves were extracted with 96% aqueous ethanol (EtOH) and was then partitioned into three layers n-hexane, dichloromethane (CH2Cl2), and n-butanol (n-BuOH). All layers were checked for their activity against breast tumor MCF-7 cells using MTT assay method. A portion of the most active layer was purified using open column chromatography to give fraction that has toxicity against zebra fish embryos. Based on the assay-guided isolation, compound 1 was isolated. The chemical structure of 1 was elucidated using nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS) data as well as comparing data with literature.Results: The CH2Cl2 layer of F. deltoidea leaves was found to inhibit breast tumor MCF-7 cells with IC50 10 µg/ml which was the most toxic among the layers. A portion of the most active layer was purified using open column chromatography to give 7 fractions. The fraction 5 showed toxicity against zebrafish embryos (LC50 35 µg/ml, 48 hpf). This fraction was purified using high performance liquid chromatography (HPLC) octadecylsilyl (ODS) column with gradient elution 70% aqueous acetonitrile (MeCN) to 100% MeCN (linear gradient) for 40 min with UV detection at 254 nm (tR = 30.99 min) to give compound 1. The chemical structure of 1 was revealed as a chlorin-type compound named methyl 10-epi-pheophorbide A.Conclusion: Methyl 10-epi-pheophorbide A was isolated for the first time from the active fraction of the Indonesian F. deltoidea leaves or tabat barito. The chemical structure including absolute stereo chemistry was elucidated using NMR and HRMS data as well as by comparison with the literature values. The 13C NMR data has been added to complete the previous report.

Synthesis and Characterization of Fluorinated Alkyl Substituted Disiloxane

2014 ◽  
Vol 529 ◽  
pp. 13-15
Author(s):  
Qing Chuan Xi ◽  
Ke Cao ◽  
Ya Wen Huang ◽  
Guan Jun Chang ◽  
Jun Xiao Yang
Keyword(s):  
High Performance ◽  
Chemical Structure ◽  
Rust Resistance ◽  
Condensation Reaction ◽  
Synthesis And Characterization ◽  
Silicon Oil ◽  
Temperature Performance ◽  
Diffusion Pump ◽  
Measurement Results

Alkyl substituted disiloxanes demonstrated promising applications as high performance hydraulic oil, diffusion pump oil, etc. In this study, fluorinated alkyl substituted disiloxane was synthesized via Grignard reaction followed by condensation reaction. Its chemical structure was verified by FTIR and NMR. Measurement results showed that this silicon oil exhibited good high temperature performance, oxidation resistance and rust resistance.

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