Synthesis and photoinitiation properties of a novel quaternary ammonium tetraphenylborate salt

Quaternary ammonium salts are photobase generators. Recently, we prepared a novel quaternary ammonium tetraphenylborate salt bearing a 6‐methoxynaphthoylmethyl group. The structure of the products was confirmed by elemental analysis and ¹H‐NMR. Thermogravimetry showed its good thermostability. UV spectra and fluorescence emission spectra of the samples were studied. A mass spectrometry method for the analysis of the tertiary amine and other fragments produced by photolysis was established. Photolysis was found to produce both tertiary amine and free radicals. Therefore, the products of photolysis not only could cause thermal curing of epoxide but also could initiate the free‐radical polymerization of acrylate or methyl acrylate monomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 399–405, 2006     

Preparation of a series of photoinitiators and their use in the thermal curing of epoxide and radical polymerization of acrylate

A series of photoinitiators, quaternary ammonium tetraphenylborate salts (QA Salts-BPh₄) with various chromophores, have been synthesized and characterized by elemental analysis (EA), ¹H NMR and IR. The photochemistry and photophysics of QA Salts-BPh₄ have been investigated by UV spectroscopy. The formation of triethylenediamine (TEDA) and phenyl free radical in the photolysis of QA Salts-BPh₄ was ascertained by mass spectrometric method. Their reactivity in the thermal curing of epoxide resin such as EPON827 and radical polymerization of acrylate monomers such as trimethylolpropane triacrylate (TMPTA) was studied. It is found that the relative initiator efficiency of QA Salts-BPh₄ is related to the structure of chromophore.     

Preparation of iodine containing quaternary amine methacrylate copolymers and their contact killing antimicrobial properties

A novel quaternary amine methacrylate monomer (QAMA) was synthesized by amination of dimethacrylate with piperazine followed by its quaternization using an alkyl iodide. Copolymerization of QAMA with 2‐hydroxyethyl methacrylate was carried out by free radical bulk polymerization technique at room temperature using ammonium persulfate and N,N,N′,N′‐tetramethyl ethylenediamine as a redox initiator. The monomer as well as copolymers was characterized by FTIR and ¹H NMR spectral studies. Thermal and physical characteristics of copolymers of varying compositions of QAMA were evaluated by thermogravimetric analysis, differential calorimetry, contact angle and scanning electron microscopy. The antibacterial activity of the synthesized quaternary amine dimethacrylate copolymers against Escherichia coli and Staphylococcus aureus was studied by zone of inhibition and colony count method. QAMA copolymers showed broad‐spectrum contact killing antibacterial properties without releasing any active agent as checked by iodide‐selective ion meter. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1038–1044, 2006     

Electrochemical polymerization of N-vinylcarbazole

The electrolysis of N-vinylcarbazole in the solution of quaternary ammonium salts in dichloroethane leads to polymer formation in the anolyte. The effect of monomer concentrations, current levels, and nature of supporting electrolytes on the polymerization has been investigated. The polymerization is free radical with bromide salt and cationic with perchlorate or hexachloroantimonate salt. The poly(N-vinylcarbazole) gets oxidized at the anode and can be cycled between the oxidized and neutral states. The oxidized polymers at the electrode may exhibit electrical conductivity.     

Polymerization of acrylonitrile using potassium peroxydisulfate as an initiator in the presence of a multisite phase‐transfer catalyst: A kinetic study

In this article, the kinetics and mechanism of the free‐radical polymerization of acrylonitrile (AN) using potassium peroxydisulfate (PDS) as a water‐soluble initiator in the presence of synthesized 1,4‐bis(triethyl methyl ammonium) benzene dichloride (DC‐X) as a phase‐transfer catalyst (PTC) were studied. The polymerization reactions were carried out under inert and unstirred conditions at a constant temperature of 60 ± 1°C in cyclohexane/water biphasic media. The rate of polymerization (R_p) increased with an increase in the concentrations of AN, PTC, and PDS. The order with respect to the monomer, initiator, and PTC was found to be 1.0, 0.5, and 0.5, respectively. R_p was independent of the ionic strength and pH of the medium. However, an increase in the polarity of the solvent slightly increased the R_p value. On the basis of the obtained results, a mechanism is proposed for the polymerization reaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and comparative solution properties of a cationic polyelectrolyte and its corresponding polyzwitterion from 1,1‐diallyl‐4‐methoxycarbonylpiperidinium chloride

The quaternary ammonium monomer 1,1‐diallyl‐4‐methoxycarbonylpiperidinium chloride was synthesized in good yield. On polymerization in water using t‐butylhydroperoxide as initiator, a cationic polyelectrolyte (CPE) with a five‐membered cyclic structure on the polymeric backbone was obtained. On acid hydrolysis, followed by basification, the CPE gave the corresponding polybetaine (PB). The solution properties of these polymers were investigated by potentiometric and viscometric techniques. The PB demonstrated “antipolyelectrolyte” behavior. The basicity constant of the carboxylate functionality in the polyzwitterionic polymers was ‘apparent’ in a 0.1 N NaCl solution and followed the modified Henderson‐Hasselbalch equation. It was found that as the degree of protonation (α) of the whole macromolecule increases, the protonation of the amine nitrogen becomes increasingly more difficult. Unlike other polyzwitterions/polybetaines, the PB was soluble in salt‐free water. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of a novel quaternary ammonium tetraphenylborate salt and its use for photo‐induced thermal curing of epoxides and radical polymerization of acrylates

A novel photoinitiator, quaternary ammonium tetraphenylborate salt bearing 4‐(4^′‐benzoylphenyl)‐acetophenone (BPPAPG), has been synthesized and characterized by elemental analysis ¹H NMR and IR. The photochemistry and photophysics of BPPAPG were investigated by UV spectroscopy. The formation of 1,4‐diazabicyclo[2.2.2]octane in the photolysis of BPPAPG was ascertained by mass spectrometry. The photoinitiation reactivity of BPPAPG was studied and the results showed that it possessed two sorts of initiation properties, ie thermal curing of the epoxy resin EPON827 and free radical polymerization of acrylates such as trimethylolpropane triacrylate. Copyright © 2005 Society of Chemical Industry     

Cyclic acetals as the second co-initiators in three-component photoinitiating systems

Cyclic acetals were used as a second co-initiator in three-component photoinitiating systems. The mixtures of cyanine dye borate ion salt and cyclic acetals were used to initiate the visible light polymerization of triacrylate monomer (TMPTA). The kinetics of polymerization was recorded by differential scanning calorimetry (DSC). The results showed that the addition of cyclic acetals increases the rate of polymerization (R _p).     

Preparation of electrorheological active ionomers from poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine)

In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K₂S₂O₈ as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, ¹H and ¹³C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H₂O) and washed with LiOH_(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006     

Photo‐induced controlled radical polymerization of methyl methacrylate mediated by photosensitive nitroxides

Photosensitive nitroxides bearing different chromophore groups (benzophenone, naphthalene and quinoline) were synthesized and characterized. The photochemical properties of the synthesized products were investigated by UV?visible and fluorescence measurements. The results indicated that an efficient energy transfer from the chromophore moiety to the nitroxide radical moiety could occur within the molecular distances. The photo‐induced nitroxide‐mediated polymerization of methyl methacrylate (MMA) was performed using the photosensitive nitroxide/2,2‐dimethoxy‐2‐phenyl acetophenone as a bimolecular mediated system. The controlled character of the polymerization was confirmed by the linear tendency of molecular weight evolution with narrow molecular weight distribution (1.3?1.4). The experimental conditions, such as type of chromophore, initiator concentration and molar ratio of initiator/nitroxide, are discussed for a better understanding of the mechanism of the controlled polymerization. Using the polymerization products as macroinitiator, the chain extension reaction of MMA turned out to be able to re‐initiate further polymerization of the monomer. © 2014 Society of Chemical Industry     

Onium Salts of Amino Acids as Co‐Initiators in Photoinduced Free‐Radical Polymerization

Summary: The onium salts of selected aliphatic and aromatic amino acids were investigated as electron donors in photoinduced free radical polymerization, in conjunction with either DIBF or BP as sensitizer. The laser flash photolysis experiments unmistakably documented that the free radical formation occurs via an electron transfer reaction from the amino acid salt to the chromophore triplet state. The kinetic studies clearly showed that either the DIBF or BP onium salts of selected aliphatic and aromatic sulfur‐containing amino acids exhibit a significant increase in the efficiency of free‐radical polymerization of TMPTA as compared to non‐sulfur‐containing co‐initiators and that the efficiency of all tested electron donors is only slightly dependent on the cation type coupled with co‐initiators tested.

Possible mechanism for the free radical photoinitiated polymerization.     

Kinetics of radical polymerization of glycidyl methacrylate initiated by multi‐site phase transfer catalyst–potassium peroxydisulfate in two‐phase system

The kinetics of radical polymerization of glycidyl methacrylate, initiated by the free radicals formed in situ in the multi‐site phase transfer catalyst (PTC), 1,1,2,2‐tetramethyl‐1‐benzyl‐2‐n‐propylethylene‐1,2‐diammonium bromide chloride–potassium peroxydisulfate system was studied in an aqueous–organic two‐phase media at 60°C ± 1°C under inert and unstirred condition. The rate of polymerization (R_p) was determined at various concentrations of the monomer, initiator, catalyst, and volume fraction of aqueous phase. The effect of acid, ionic strength, and water‐immiscible organic solvents on the R_p was examined. The temperature dependence of the rate was studied, and activation parameters were calculated. R_p increased with an increase in the concentrations of monomer, initiator, multi‐site PTC, and increase in the polarity of solvent and temperature. The order with respect to monomer, initiator, and multi‐site PTC was found to be 0.50. A feasible free‐radical mechanism consistent with the experimental data has been proposed, and its significance was discussed. The synthesized polymer was confirmed by Fourier transform infrared spectral analysis. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Photo‐mediated metal free atom transfer radical polymerization of acrylamide in water

Photo‐mediated metal free atom transfer radical polymerization of acrylamide was conducted at 25 °C in water under visible light irradiation with water soluble 2‐hydroxy‐3‐(4‐benzoylphenoxy)‐N,N,N‐trimethyl‐1‐propaminium chloride (HBTPC) as photoredox catalyst and 2‐hydroxyethyl 2‐bromoisobutyrate as alkyl halide. The polymerization followed first‐order reaction kinetics. The living character of photo‐mediated atom transfer radical polymerization of acrylamide was verified by the linear development of the polymer number average molar mass (M_n,GPC) with monomer conversion and narrow molecular weight distributions (?). The effects of acrylamide concentration, light intensity, amount of HBTPC, and tris(2‐dimethylaminoethyl)amine on polymerization were investigated. Increasing monomer concentration led to a higher M_n,GPC values with narrow ?. The polymerization rate increased with increasing the amount of monomer, light intensity, HBTPC and tris(2‐dimethylaminoethyl)amine. The polymerization was monitored by the periodic light on/off. The structure of polyacrylamide was analyzed by proton nuclear magnetic resonance spectrometer and gel permeation chromatography. Successful chain extension experiments show the controlled nature of the polymerization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46567.     

Novel addition-fragmentation agent in cationic photopolymerization

The aim of present study is to examine the photo-initiation efficiency of N,N-dimethylacrylamide-based allylic ammonium salt as one component addition-fragmentation agent (cationic photoinitiator cum radical source) in free radical accelerated cationic polymerization. Novel addition-fragmentation agent (AFA), 2-(N,N-dimethylcarboxy-3-propenyl)(phenylcarbonyl-4-phenylene) dimethyl ammonium hexafluoroantimonate (DMPDA) was synthesized as cationic photoinitiator and its initiation efficiency was examined in polymerization of cyclohexene oxide (CHO), isobutyl vinyl ether (IBVE), and n-butyl vinyl ether (n-BVE) in CH₂Cl₂ solvent at wavelength λ > 290 nm. The rate of polymerization increases with the increase in initiator concentration and reaction time. The results demonstrate that DMPDA acts as an efficient photoinitiator (AFA) without use of radical source in free radical accelerated cationic polymerization.     

Addition–Fragmentation Reactions for Cationic Polymerization using a Novel Allyloxy-picolinium Salt

A novel allyloxy-picolinium salt, N-[2-(methyl)allyloxy]-α-picolinium hexafluoroantimonate, has been synthesized and used as addition–fragmentation agent for radical promoted thermal and photochemical cationic polymerization of monomers such as cyclohexene oxide, p-methoxystyrene and various vinyl ethers. Polymerization by heat was achieved using the allylic salt in conjunction with benzoyl peroxide (BPO), phenylazotriphenylmethane (PAT) and 2-2′-azobis-isobutyronitrile (AIBN). Polymerization rates were found to drop in the order PAT>BPO>AIBN. Photopolymerization was carried out by irradiating the allyloxy-picolinium salt in the presence of monomer at 280nm. Upon adding benzoin as free radical source, the spectral response was extended to 370nm. The initiation mechanism is explained in terms of an addition–fragmentation scheme. © 1997 SCI.     

Polymérisation des méthacrylates d'ethers glycériques par le peroxyde de benzoyle: Accélération de la polymérisation par les sulfinates d'amines tertiaries

The kinetic study of the radical polymerization of phenyl glyceric ether methacrylate, taken as model of the corresponding derivative of bisphenol A, initiated by the system benzoyl peroxide/dimethyl p-toluidine p-toluene sulfinic acid salt, was performed. The effect of hydroxylic groups of the monomer on the polymerizability was established. The system used as initiator allows rapid polymerization of the monomer in presence of stabilizers.     

Study on synthesis and photochemical behavior of carbamate photobase generators for fluorescence imaging

A fluorescence imaging system is designed based on the photodecomposition of photobase generators embedded in polyvinyl butyral (PVB) matrix. These photobase generators were synthesized with propyl and phenethyl units served as leaving groups, and phthalimido, succinimido, di‐2‐thienyl ketoximino, and benzophenoneoximino units acted as photosensitive species, respectively. The influences of the two leaving groups and four photosensitive species on the photochemical behavior were investigated in detail. The results demonstrate that the photochemical properties of these photobase generators depend on the photosensitive species other than the leaving groups. And further study shows that succinimido propylcarbamate (SPrC) exhibits the best thermal stability and relatively quick rate of photodecomposition among all the photobase generators. Therefore, a PVB film embedded with SPrC is used as a fluorescence imaging material. The patterned fluorescence image obtained from the fluorescamine‐treated irradiated PVB film showed bright green fluorescence, which provides potential application for optical storage or color electronic displays. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41058.     

Emulsifier‐free cationic latexes based on vinylbenzyl chloride and 2‐(dimethylamino)ethyl methacrylate with adjusted hydrophilic–hydrophobic properties

Functional emulsifier‐free cationic latexes based on styrenic monomer vinylbenzyl chloride (VBC) and acrylic monomer 2‐(dimethylamino)ethyl methacrylate (DMA) were successfully prepared with dual quaternary ammonium ions (36–63 mol %) on both monomer moieties in two‐stages. First, [2‐(methacryloyloxy)ethyl]dimethylhexadecylammonium bromide monomer (DMA(C₁₆)), prepared via quaternization of DMA with 1‐bromohexadecane, was utilized as a comonomer (5–20%) as well as a surfactant in the emulsion polymerization of VBC. Next, the quaternization of chloromethyl groups in the VBC moiety in latex particles with trimethylamine and N,N‐dimethylhexadecylamine created a second type of quaternized sites on the latex particles. The percentages of the quaternary ammonium ions of the first‐stage latexes (P[VBC‐DMA(C₁₆‐x)]) and the second‐stage latexes (P[VBC(R)‐DMA(C₁₆‐x)]) were determined using bromide and chloride ion‐selective electrodes. The particles were characterized with a scanning electron microscope, Zetasizer, measuring water contact angles of their pellets. The polymer structure and the alkyl group length in their quaternary ammonium ions played an important role on the sizes, zeta potentials and hydrophilic–hydrophobic balances of the latexes. The water contact angles of the pellets of the latex particles varied from 50.3 to 109.6° depending on both the polymer structure and the alkyl group length. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42775.     

Synthesis and photo‐curing behaviors of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers

A series of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers used in nano‐imprint lithography resists were synthesized and subjected to photo‐initiated polymerization. The surface energies of the monomers and the resulting polymer films were then investigated. The surface energies of the monomers were very low at less than 15 mJ m^–2. The photo‐curing behaviors of the five hybrid monomers were investigated using real‐time Fourier transform infrared spectroscopy. The monomers were sequentially initiated with cationic (PAG201) and mixed (cationic initiator PAG201, radical initiator ITX or TPO) initiators. The vinyl ether double bond polymerized both rapidly and completely, whereas the allyl ether double bond remained when PAG201 was used as the photo‐initiator and polymerized completely with mixed initiators. The different double bonds of the silicon‐containing (vinyl ether)–(allyl ether) hybrid monomer increased the efficiency of the polymerization and overcame the intrinsic limitations of the free radical and cationic polymerization processes, including strong oxygen inhibition, large volume shrinkage and high humidity sensitivity. The five monomers with low viscosity, low surface energy, good thermal stability and good photo‐polymerization properties were suitable for nano‐imprint photoresists. © 2013 Society of Chemical Industry     

Synthesis and characterization of novel oligomeric poly(styrene‐co‐acrylonitrile)–clay complexes

Oligomeric poly(styrene‐co‐acrylonitrile) quaternary ammonium salts were prepared through reactions of trimethylamine with corresponding poly(styrene–acrylonitrile–vinyl benzyl chloride)s, which were synthesized by the free‐radical polymerization of a mixture of styrene, acrylonitrile, and vinyl benzyl chloride. Then, oligomeric poly(styrene‐co‐acrylonitrile)‐modified clays were prepared through the cation exchange of the sodium ions in the clay with the corresponding poly(styrene‐co‐acrylonitrile) quaternary ammonium salts. The poly(styrene–acrylonitrile–vinyl benzyl chloride)s, poly(styrene‐co‐acrylonitrile) quaternary ammonium salts, and their clay complexes were characterized with infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, proton nuclear magnetic resonance, X‐ray diffraction, and transmission electron microscopy. X‐ray diffraction and transmission electron microscopy studies showed that these novel clay complexes were well intercalated. Furthermore, thermogravimetric analysis data indicated that this series of polymerically modified clays had high enough thermal stability for nanocomposites by melt blending. The thermal treatment of one of these novel clays at 250°C under nitrogen was also conducted. Solubility and infrared studies of this thermally treated clay complex revealed that a novel polyimine/enamine structure clay complex had been formed in the gallery of the clay. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009