Benzophenone-sensitized photopolymerization of methyl methacrylate using dimethyl aniline–maleic acid combination as photoinitiator

Benzophenone (BP)-sensitized photopolymerization of methyl methacrylate (MMA) in near UV/visible light was studied at 40°C using dimethylaniline maleic acid (DMA—MA) combination as the photoinitiator. An instantaneous 1:1 complexation between DMA and MA takes place when they are mixed together in acetonitrile. Also, instantaneous complex formation occurs between DMA and MMA and between MA and MMA when they are dissolved in MMA in low concentrations, separately. Interestingly, when equimolar proportions of DMA and MA are mixed together in MMA, there is indication for further instantaneous complexation between (DMA—MMA) complex and (MA—MMA) complex forming the actual initiating species in the photopolymerization system. Initiator exponent was 0.28 and monomer exponent varied between 0.0 to 1.8 depending on the nature of the solvent and range of dilution used. Analysis of kinetic data indicates a free radical mechanism for the polymerization with initiator-dependent termination. Chain termination via degradative initiator transfer is quite significant; but the degradative effect becomes much less prominent in the higher range of initiator concentration indicating that the reinitiation reaction following the initiator transfer process assumes more proportionate significance as the initiator concentration is increased, probably as a result of higher reinitiation efficiency. Polymers obtained gave evidence for the incorporation of aromatic (amine) end groups in them.     

Determination of amines as pentafluoropropionic acid anhydride derivatives in biological samples using liquid chromatography and tandem mass spectrometry

Determination of amines in biological samples as markers of exposure to the amines or the corresponding isocyanates is an important tool for industrial exposure assessment. In this study, a liquid chromatography and tandem mass spectrometry (LC-MS/MS) method for determination of amines in biological samples as perfluorofatty amides derivatives is presented. The method enables determination of diamines such as methylene diamine (MDA), toluene diamine (TDA), naphthalene diamine (NDA), hexamethylene diamine (HDA), isophorone diamine (IPDA), methylenedi(cyclohexylamine)(HMDA) and 4,4'-methylene-(2-chloroaniline)(MOCA) in human urine and plasma. The work-up procedure included hydrolysis of the biological samples with 3 M H(2)SO(4) at 100 degrees C for 16 h and extraction of the amines into toluene, where derivatisation of the amines with perfluorofatty acid anhydride was performed. Following removal of excess reagent and the acid formed and an exchange of solvent, the derivatives were analysed using gradient elution with an acetonitrile/water mobile phase composition and electrospray ionisation (ESI) with multiple reaction monitoring (MRM) of [M - H](-)-->[M - H - 120](-) or [119](-). Several perfluorofatty acid anhydrides were evaluated as derivatisation reagents, but the LC chromatographic properties of the pentafluoropropionic acid anhydride (PFPA) derivatives were favourable. Quantification of amine-PFPA derivatives was performed using deuterium labelled amine-PFPA derivatives as internals standards with good precision and linearity in the investigated range of 0-20 ng ml(-1) urine. The instrumental detection limits for the amine-PFPA derivatives were 0.2-3 fmol for MRM of [M - H](-)-->[119](-) and 0.3-8 fmol for [M - H](-)-->[M - H - 120](-). In 10 urine and 6 plasma samples from workers exposed to isocyanates, determination of TDA and MDA as PFPA derivatives was performed using LC-MS/MS and a reference GC-MS method. No significant difference between the two methods was observed.     

Further studies on homopolymers and copolymers resulting from the reaction of polymaleic anhydride with alcohols and amines

Polymaleic anhydride prepared by γ-rays irradiation of maleic anhydride was used as a reactive polymer and reacted with certain long-chain aliphatic amines and/or alcohols as well as with the mesogenic biphenylamine. The homopolymers and copolymers that were prepared, i.e., derivatives of N-alkyl polymaleamic acid, monoesters of polymaleic acid, or mixed amide-ester derivatives, were primarily investigated as far as their property to show thermotropic liquid crystalline character is concerned. By this investigation the structural features for the exhibition of mesomorphism by these polymers were determined.     

Spiro-β-lactame durch [2+2]-Cycloaddition von Ketenen an Iminolactone

Spiro-β-lactams from [2+2]-Cycloaddition of Ketenes to Iminolactones Iminolactones (‘Isoimides’) derived from maleic anhydride and amines are shown to react with various ketenes in a [2+2]-cycloaddition mode. Either preformed ketenes or the combination acid chloride/tertiary amine can be used as reagent. The reaction products have been assigned the spiro-β-lactam structure. Unsubstituted ketene is inert under the reaction conditions. It is possible to synthesize the spiro-β-lactams in a one-pot procedure, starting from a mixture of maleic anhydride/amine and excess dialkylketene.     

Mechanistic studies on ceric-amine initiated aqueous polymerization of methylmethacrylate by endgroup analysis

Summary Endgroup analysis of polymethylmethacrylate obtained by initiation with Ceric ion-amine initiator systems in acid aqueous media has been carried out using Palit's dye partition technique. The amines used are diethylamine, triethylamine, mono-ethanolamine, diethanol amine and triethanol amine and also ethylene diamine. All the amines incorporated amine endgroups in the polymer samples to the extent of approximately one endgroup per chain, except ethylene diamine which incorporated approximately two amine endgroups per macromolecule. Besides amine endgroups, the three ethanol amines incorporated hydroxyl endgroups to different extents depending on the hydroxyl content of the particular compound. In the light of endgroup results initiation through amine, ethylene diamine or ethanol amine radicals have been suggested. Probable termination mechanism has also been discussed.With 3 tables     

The synthesis of novel macrocyclic multidentate compounds from dioxodioic acids

A series of novel macrocyclic multidentate crown compounds have been prepared from a series of dioxodioic acids. The dioxodioic acids were prepared by treating various oligoethylene glycols or amines with maleic, succinic, citraconic, and glutaric anhydrides. The crown compounds were then synthesized from the dioxodioic acid chlorides obtained from the diacids and various oligoethylene glycols or ethylene diamine. The following macrocyclic compounds have been prepared: 1,4,9,12-tetraoxacyclohexadecane-5,8,13,16-tetrone ( 1 ); 1,4,7,10,15,18-hexaoxacyclodocosane-11,14,19,22-tetrone ( 2 ); 1,4-dioxa-9,12-diazacyclohexadecane-5,8,13,16-tetrone ( 3 ); 1,4,7-trioxa-12,15-diazacyclonoadecane-8,11,16,19-tetrone ( 4 ); 1,4,7,10-tetraoxa-15,18-diazacyclodocosane-11,14,19,22-tetrone ( 5 ); 4-benzyl-1,7,12,15-tetraoxa-4-azacyclonona-decane-8,11,16,19-tetrone ( 6 ); 1,4,7,12,15,18-hexaoxacyclodocosa-9,20-diene-8,11,19,22-tetrone( 7 ); and 9,21-dimethyl-1,4,7,12,15,18-hexaoxacyclodocosa-9,20-diene-8,11,19,22-tetrone ( 8 ) (Figure 1).     

Non-extractable photoinitiators based on thiol-functionalized benzophenones and thioxanthones

Non-extractable photoinitiators could be advantageous for use in biological, electronic, and food packaging applications. Therefore, thioxanthone and benzophenone derivatives were synthesized from 1,6-hexane dithiol and chlorinated benzophenone or thioxanthone. The efficiency of thiol-functionalized photoinitiators in combination with amine co-initiators was compared to benzophenone and isopropylthioxanthone with amine co-initiators, and the cleavage of photoinitiator 2,2-dimethoxy-1,2-diphenylethan-1-one in acrylic resins. The reaction kinetics were analyzed using photo-differential scanning calorimetry and real-time FTIR. Coating physical properties were evaluated by pendulum and pencil hardness, steel-wool scratch and mandrel bend tests. The non-extractable photoinitiators had higher absorbance than their benzophenone or isopropylthioxanthone counterparts due to the sulfide substitution on the phenyl ring, and the free thiol groups reacted with the acrylate by either an amine catalyzed Michael addition or a free-radical chain process. The combination of thiol-functionalized photoinitiators with secondary amines provides an efficient photoinitiator system that is locked into the photopolymerized network and cannot be extracted with typical solvents.     

Synthesis and photopolymerization kinetics of benzophenone piperazine one‐component initiator

A one‐component type II photoinitiator (PDBP), based on 4‐hydroxybenzophenone (HBP), acryloyl chloride, and piperazine, was synthesized and its structure was confirmed by ¹H‐NMR. The photopolymerization kinetics of the photoinitiator was studied by real‐time Infrared spectroscopy (FT‐IR). It indicated that PDBP was a more effective photoinitiator than that of BP/triethylamine (TEA). The rate of polymerization, final conversion increased and the induction period shortened with increase in PDBP concentration, light intensity, and amine concentration. The kinetics of photopolymerization for TPGDA incorporating PDBP in the presence of different tertiary amines as the initiating system indicated that the PDBP/TEA combination exhibited the highest polymerization rates among the PDBP/amine combinations. Copyright © 2007 John Wiley & Sons, Ltd.     

Radiation Chemical Studies of Protein Reactions: Effect of Chelating Agents on the Breaking of Secondary Bonding in Protein

The radiation protective effect of the breaking of secondary bonding in proteins was examined with 1,2 diamine and 1,2 dihydroxy derivatives such as ethylenediamine, ethylenediaminetetraacetic acid, and propylene glycol, and monosubstituted amines and alcohols such as ethylamine and n-propyl alcohol. An empirical equation for the viscosity change was obtained.     

Reactions on polymers with amine groups. I. Reactions of vinylpridine polymers and of their model compounds with unsaturated carboxylic acids

The reactions of vinylpyridine polymers with α,β-unsaturated carboxylic acids such as acrylic, methacrylic, crotonic, itaconic, cinnamic, fumaric, and maleic acids were studied. It was found that, when reacted with acrylic, itaconic and fumaric acids. poly(4-vinylpyridine) gave macromolecular betaine products while with maleic acid, betaine as well as the corresponding salt was obtained. Poly(2-vinylpyridine) reacted with the same acids as poly(4-vinylpyridine) gave only the salts. No significant changes were observed with the two polymers when reacted with methacrylic, crotonic, and cinnamic acids. To attempt to rationalize these observations with the two macromolecular tertiary amines, the reactions of 4-methyl and 2-methylpyridines with the same carboxylic acids were investigated. The ¹H-NMR methodology was generally applied to elucidate the chemical structure obtained. © 1995 John Wiley & Sons, Inc.     

Preparation of poly(glycidylmethacrylate‐divinylbenzene) weak acid cation exchange stationary phases with succinic anhydride,phthalic anhydride,and maleic anhydride for ion chromatography

In this work, poly(glycidylmethacrylate‐divinylbenzene) microspheres were prepared and applied for the preparation of weak acid cation exchange stationary phases. Succinic anhydride, phthalic anhydride, and maleic anhydride were selected as carboxylation reagents to prepare three weak acid cation exchangers by direct chemical derivatization reaction without solvent or catalyst. The diameters and dispersity of the microspheres were characterized by scanning electron microscopy; the amount of accessible epoxy groups and mechanical stability were also measured. The weak acid cation exchangers were characterized by Fourier transform infrared spectroscopy; the content of carboxyl groups was measured by traditional acid base titration method. The chromatographic properties were characterized and compared by separating alkali, alkaline earth metal ions and ammonium and polar amines. The separation properties enhanced in the order of succinic anhydride, phthalic anhydride, and maleic anhydride modified poly(glycidylmethacrylate‐divinylbenzene) cation exchangers.     

Kinetic studies on the homogeneous hydrogenation of fumaric and maleic acid catalysed by bis(dimethylglyoximato)cobalt(II)

The influence of varying concentrations of Co(dmgh)₂, NaOH and axial base on the rate of hydrogenation of fumaric and maleic acids has been studied in detail. Intramolecular hydrogen bonding in the monoanion of maleic acid and thetrans orientation of carboxylic acid groups in fumaric acid are important factors which account for the difference in the rate of hydrogenation of these substrates. Mono-, di-and trialkyl amines as axial bases modify the activity of the catalyst, dialkylamines conferring the maximum activity and trialkylamines the least. Back-strain on nitrogen atom and solvation energy of the amines are responsible for their different behaviours. A rate law has been proposed and verified     

Influence of polar modifiers on microstructure of polybutadiene obtained by anionic polymerization. Part 3: Lewis acid alkoxide (μ) and Lewis base amine,amine-ether,and ether mixed-type (σ+μ) polar modifiers

The influence of mixtures of sodium mentholate (SMT) as a Lewis acid polar modifier and different Lewis base polar modifiers (amines, amine-ethers, ethers) on the microstructure of polybutadiene obtained by anionic polymerization was studied and compared to the influence of the same polar modifiers used separately. Detailed characterization of the polybutadienes in terms of the content and distribution of butadiene isomeric repeating units was performed by ¹³C NMR and supported by FT-IR-ATR and ¹H NMR data analysis. The results obtained indicated that the use of a mixture of Lewis acid and Lewis base in most cases enhanced formation of 1,2 butadiene structures in comparison to the Lewis bases used separately. However, application of a mixture of SMT and DTP resulted in lower vinyl content than when DTP was applied alone. It is worthwhile to note that the combination of a Lewis acid (SMT) and one of Lewis bases tested (DMEAEE) enabled obtaining very high vinyl polybutadiene (88% ¹H NMR, 96% ¹³C NMR).     

Photochemical synthesis of nitroxyl free radicals in the presence of vinyl monomers

The photochemical formation of an inhibitor in the presence of monomers and a photoinitiator offers the possibility of producing positive two-step photoresists. As inhibitor precursor sterically hindred amines have been used in the presence of air oxygen and Rose Bengal as oxidation photosensitizer. On irradiation with visible light (546 nm). stable nitroxyle radicals are formed, which act as strong inhibitors of free radical polymerization. Hexanediol diacrylate and 2-acryloxy-2′-propionyl oxydiethylether were used as monomers. The photoinitiator required for the second step polymerization is benzoin isopropyl ether, which photolyzes on irradiation at 340 n,. The quantum yield of nitroxyl radical formation has been determined in solution and in polymeric films. Polymerization inhibition experiments were carried out with methyl methacrylate in solution and with neat monomers. Though the quantum yield Φ_NO° is low, especially in the last case, the experiments confirm the possibilities of this two-step procedure.     

Preparation and applications of weak acid cation exchanger based on monodisperse poly(ethylvinylbenzene-co-divinylbezene) beads

New technology is reported here for the synthesis of an effective weak acid-cation exchanger for ion chromatography. Monodisperse macroporous poly(ethylvinylbenzene-co-divinylbezene) (PEVB-DVB) beads of 5 microm diameter were prepared by a two-step swelling and polymerization method. Then carboxyl groups were introduced by polymerization of maleic anhydride with unreacted vinyl groups on the resin beads, followed by hydrolysis of the maleic anhydride groups. A column packed with the carboxylate beads was used to separate alkali and alkaline earth metal ions in a single isocratic run. Separations were found to be better than those with similar resin particles that are simply coated with maleic acid. The columns containing the new particles were 100% compatible with solvents commonly used for HPLC. Additionally, the prepared column was stable and could be used for a long time in a wide range of pH. The column gave good resolution, low detection limits and good repeatability for the separation of common cations. Satisfactory results were also obtained for separations of organic amines and of common cations in rainwater.     

Photoinitiators with functional groups. VII. Covalently bonded camphorquinone—amines

Camphorquinone (CQ), a widely used photoinitiator (PI) in dental applications, was covalently bonded to aromatic amines to enhance the rate of electron and proton transfer effect due to the close vicinity of the diketone and the amine group. 10‐bromocamphorquinone and 10‐bromomethylcamphorquinone were selected as suitable precursors for esterification with the carboxyl group containing aromatic amines based on 4‐dimethylaminobenzoic acid. Properties of the new photoinitiating systems were investigated by UV spectroscopy and differential scanning photocalorimetry in lauryl acrylate. Compared to physical mixtures, in all cases similar or even better performance was obtained. Surprisingly, 10‐acetyl derivatives 7 – 9 and 18 especially, were found to be highly reactive. Compared to CQ/ethyl 4‐dimethylaminobenzoate, the rate of photopolymerization was increased by a factor of up to 2. Intramolecular reaction was confirmed by photo‐differential scanning calorimetry experiments with varying PI concentrations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4948–4963, 2004     

低分子量有机胺的离子色谱法研究

 首次应用ＣＳ１２分离柱对１０种低分子量有机胺的离子色谱法进行了研究。采用了有机改进剂（乙腈），优化了色谱条件，建立了Ｃ４以下的有机胺的分析新方法。方法简便、快速、灵敏，可同时测定碱金属和碱土金属离子，准确度和精密度均满足分析要求。     

氨基改性聚醚硅油的合成、结构表征及应用

在Pt催化剂的作用下，利用含氢硅油与烯丙基缩水甘油醚、烯丙基聚氧乙烯聚氧丙烯醚的硅氢化加成反应合成聚醚／环氧硅油中间体，然后分别用吗啉、乙二胺、N,N-二甲基丙二胺、N-氨乙基哌嗪等氨解开环，制得了一系列氨烃基改性聚醚硅油AMPES，对其进行了结构表征和应用。结果表明：增加含氢硅油的数均分子量，提高硅含量，可改善AMPES的柔软性，而对织物的吸湿性影响不大。     

双功能聚合物基质阳离子交换固定相的制备及其在离子色谱中的应用

离子色谱是分离分析阳离子型化合物的重要手段之一。高效阳离子交换固定相的制备研究对离子色谱技术的发展具有重要的意义。该文以丙烯酸和顺丁烯二酸酐为单体,2-巯基乙基磺酸钠为巯基改性剂,提出了聚合物基质微球巯基改性自由基聚合修饰方法,用以制备新型双功能的阳离子交换固定相。该固定相以羧基和磺酸基为功能基,仅用简单的强酸淋洗液便可以实现常规阳离子的基线分离。利用色谱学模型,对金属离子和有机胺的保留行为进行了研究。采用梯度淋洗模式,可在24 min内实现10种阳离子的分离,表明固定相具有优异的色谱性能。“巯基-烯”修饰方法简单、高效。此外,通过调节巯基改性剂的比例能够实现对固定相交换能力的调控。     

Polymeric Photoinitiator Containing In‐Chain Thioxanthone and Coinitiator Amines

Summary: A polymeric photoinitiator (PTXP) containing in‐chain thioxanthone (TX) and coinitiator amines was synthesized by step‐growth polymerization, as well as low‐molecular‐weight model compounds. Photopolymerizations of methyl methacrylate (MMA) initiated by these photoinitiator systems were studied. Compared with corresponding low‐molecular‐weight model compounds, PTXP has a similar UV‐vis spectrum with a red‐shifted maximum absorption, and weaker fluorescence emission, and can photoinitiate the polymerization of MMA more effectively.

The structure of PTXP, the photoinitiator synthesized here.