新型的香豆素染料/碘( )盐光敏引发系统的研究

在实际应用中,大部分光敏引发系统只对紫外光敏感.近年来,随着Ar+(488nm)、YAG(532nm)以及He-Ne(633nm)激光技术的不断发展,高效的长波长光敏引发体系成为研究的重点.其中之一的方法是使引发剂直接感可见光,然而取得的结果并不显著.所以染料敏化又一次成为焦点.其中最重要的技术是使光敏引发系统的吸收波长移向长波长,并且具有高的灵敏度.     

钍（Ⅳ）与偶氮溴膦—mB和溴化十四烷基吡啶在乙醇—水溶液中的显色反应及其分

在ｐＨ１￣２的酸性介质中,钍（Ⅳ）与偶氮溴膦－ｍＢ（ＢＰＡｍＢ）形成最大吸收波长（λｍａｘ位于６８６ｎｍ的蓝色络合物,摩尔吸光系数（ε）为８．２７×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１。在有少量乙醇存在的０．５￣１．０ｍｏｌ／Ｌ盐酸溶液中,钍（Ⅳ）能与ＢＰＡｍＢ和溴化十四烷基吡啶形成更灵敏的三元络合物,最大吸收位于６９５ｎｍ,具有更大的对比度（Δλ＝１３５ｎｍ）和更高的灵敏度。ε值达１．４１×１０     

安替比林基重氮氨基─2，4─二硝基苯与锌的显色反应及其应用

研究了安替比林基重氮氨基－２．４－二硝基苯（ＡＰＤＮＢＴ）与锌（Ⅱ）的显色反应。在Ｔｒｉｔｏｎ－Ｘ－１００存在下，ｐＨ１０．０～１２．５硼砂缓冲介质中，试剂与锌形成１∶３的黄色配合物。在４５０ｎｍ和５３５ｎｍ波长下，配合物对试剂有大的吸光度差值，其以４５０ｎｍ为参比波长，５３５ｎｍ为测量波长，提出的方法，用于人发及食品中锌的测定，结果与原子吸收法一致。     

2－（2－噻唑偶氮）－5－〔N，N－二羧基甲基）氨基〕苯甲酸与钯显色反应的研究及其应用

报道了一种对钯离子具有高灵敏度和选择性的新试剂２－（２－噻唑偶氮）－５－［（Ｎ，Ｎ－二羧基甲基）氨基］苯甲酸（ＴＡＤＣＡＢ）。在０．５ｍｏｌ／ＬＨＮＯ＿３介质中，ＴＡＤＣＡＢ与Ｐｄ（Ⅱ）形成蓝色配合物，组成为Ｐｄ：ＴＡＤＣＡＢ＝１：２，最大吸收波长６５２ｎｍ。钯浓度在０～１．４μｇ／ｍＬ范围内符合比耳定律。用双波长法测定，表观摩尔吸光系数ε＿（６５２．０～５３３．６）＝８．２×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），可以允许大量金属离子共存。所确立的方法无需掩蔽剂和其它分离手段，即可直接用于Ｐｔ－Ｐｄ催化剂中微量钯的测定，结果满意。     

Mo(Ⅵ)-5-溴水杨基荧光酮-CTMAB显色反应的研究及应用

研究了新的三元配合物体系Ｍｏ（Ⅵ）－溴水杨基荧光酮－ＣＴＭＡＢ显色反应的条件,最大吸收波长λｍａｘ在５２８ｎｍ,试剂λｍａｘ在４６８ｎｍ,对比度为６０ｎｍ,ε５２８＝１．４７＊１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。该体系选择性好,方法简便、快速,用于测定水样中微量钼,结果满意。     

新试剂1-(2,3,5-三氮唑偶氮)-2-萘酚与锌的显色反应研究及应用

研究了１－（２,３,５－三氮唑偶氮）－２－萘酚（ＴＺＡＮ）锌显色反应,结果表明,在ＰＨ６．０－８．５的乙醇水溶液中ＴＺＡＮ与锌形成稳定的红色络合物,其最大吸收波长为５２５ｎｍ,表观摩尔吸光系数为３．５６＊１０＾４Ｌ．同,络合物的组成为Ｚｎ：ＴＺＡＮ＝ｌ：２,锌浓度在０－１．２μｇ．ｍｌ＾－１范围内遵守比耳定律,方法用于人发中微量锌的直接测定,结果满意。     

固体表面室温燐光法测定淫羊藿甙

１引言 淫羊蕾甙（ｉｃａｒｉｉｎ）为中草药淫羊蕾的主要有效成分,有增加冠脉血流量的作用。淫羊蕾甙的测定方法有薄层扫描法,高效液相色谱法等。固体表面室温光法是一种微量技术与痕量分析相结合的分析方法,而建羊蕾甙的室温光法的研究未见文献报道。本文以Ｄｄ（Ａｃ）２为重原子微扰剂,以聚酰胺膜作基质时,能诱导出淫羊藿甙的ＲＴＰ发射。其激发波长为３００ｎｍ（弱峰）和４００ｎｍ（强峰）,发射波长为５００ｎｍ。淫羊藿甙含量在１．３５～６７５ ｎｇ／斑范围内与ＲＴＰ强度呈良好的线性关系,检出限达０,０６ ｎｇ／斑。该…     

孔雀石绿增感聚苯乙炔的光导体

采用电位放电技术研究孔雀石绿（ＭＧ）增感顺式聚苯乙炔（ｃｔ－ＰＰＡ）光导体的光敏性，发现孔雀石绿是顺式聚苯乙炔新的有效增感剂。以Ａｌ／ｃｔ－ＰＰＡ：ＭＧ：ＰＣ（１００：５：１０）（１～１．５μｍ）／ＰＶＫ：ＴＰＡ：ＰＣ（１０：１０：１）（１５～２０μｍ）构成的光导体显示好的光敏性：表面接受电位，Ｖｍａｘ＞７００Ｖ；残余电位，Ｖｍｉｎ＜５０Ｖ；暗衰速率，ＲＤ＜１０Ｖ／ｓ；光衰放电量，△Ｖｔ＞５０％（１．０ｓ）；半衰时间，Ｔ１２＝０．８７Ｓ；感光灵敏度，Ｓ＝２．３×１０－３（１ｘ．ｓ）－１，较未增感ＰＰＡ光导体有较大的提高。ＭＧ对ＰＰＡ为光谱增感     

锆—氟—7—碘—8—羟基喹—5—磺酸—EDTA—表面活性剂体系的荧光光度研究

在ＰＨ５．５－７．０的ＨＡｃ－ＮａＡｃ缓冲溶液中，锆与氟、７－碘－８－羟基喹啉－５磺酸、ＥＤＴＡ及十六烷基溴化铵形成五元荧光络合物，其组成为Ｚｒ（Ⅳ）：Ｆ：Ｈ２ＱＳＩ：ＥＤＴＡ：ＣＴＭＡＢ＝１：２：１：１：４。络合物的最大激发波长（λｅｘ）为３６５ｎｍ，最大发射波长为５００ｎｍ。     

乳化剂OP存在下桑色素与Al（Ⅲ）Mo（Ⅵ）显色反应的研究及应用

研究了非离子型表面活性剂ＯＰ存在下，桑色素与Ａｌ（Ⅲ）Ｍｏ（Ⅵ）显色反应的适宜条件。在０．１２ｍｏｌ．Ｌ＾－１乙酸介质中，桑色素与Ａｌ（Ⅲ）的配合物最大吸收波长为４２０ｎｍ，表观摩尔吸光系数为１．３７＊１０＾５，Ａｌ（Ⅲ）浓度在０－２．０μｇ／１０ｍｌ范围内呈良好的线性关系。     

DYE-SENSITIZED PHOTOPOLYMERIZATION OF METHYL METHACRYLATE INITIATED BY COUMARIN DYE/IODONIUM SALT SYSTEM*

The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarindye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiatorrespectively, can be used to initiate the polymerization of methyl methacrylate (MMA). The results showedthat when exposed to visible light, coumarin dye/iodonium salt undergoes quick electron transfer from DEDCto DIHP and free radicals are produced. The visible light photoinduced reaction between DEDC and DIHP ismainly through the excited singlet state of DEDC and thus it is a little sensitive to O_2. The influence ofconcentration of DEDC, DIHP and MMA on the rate of photopolymerization of MMA was also investigated.     

Polymerization of methyl methacrylate using isatoic anhydride–bromine donor–acceptor complex as the photoinitiator

Isatoic anhydride (IA) alone did not initiate photopolymerization of methyl metacrylate (MMA) at 40°C when exposed to visible light for about 180 min. But IA, when used in combination with bromine (Br₂) as the initiator, initiated the photopolymerization of MMA readily under the same conditions. This behavior was explained by the formation of a donor-acceptor type of complex between IA and Br₂ in the presence of MMA. The polymerization was found to proceed via a free radical mechanism and the radical generation process was considered to follow an initial complexation reaction between the initiator components and monomer. The complex initiator showed nonideal kinetics for the present system (initiator exponent < 0.5) and was analyzed. The monomer exponents varied from 0.83 to 1.15 normally depending on the nature of solvent used. Initiator-dependent chain termination was significant as well as the bimolecular mode of chain termination. © 1993 John Wiley & Sons, Inc.     

Kinetic Investigation on the Photopolymerization of Methyl Methacrylate Using Iodine Trichloride as Initiator

The photopolymerization of MMA in visible light was studied at 45°C using IC1₃ as the photoinitiator. The initiator exponent was found to be 0.16 and the monomer exponent varied between 1.0 to 1.50, depending on the nature of the solvent. Analysis of the data revealed that the polymerization was induced by a free radical mechanism. Nonideality of the kinetics was explained on the basis of 1) Monomer-dependent chain initiation and 2) Initiator-dependent chain termination via degradative initiator transfer.     

衣康酸系铜离聚体引发下的甲基丙烯酸甲酯聚合反应

本文报道了衣康酸系铜离聚体引发下的甲基丙烯酸甲酯(MMA)聚合反应,对影响反应的各种因素、反应机理及反应动力学进行了研究。     

Use of an Internal Keto-Imino Compound as the Photoinitiator in the Polymerization of Methyl Methacrylate

Photopolymerization of MMA in visible light was studied at 40°C using acridone as the photoinitiator. The polymerization was found to proceed via a free radical mechanism and the radical generation process was considered to follow an initial complexation reaction between monomer and acridone. Kinetic data indicated a lower order dependence of R_p on the initiator concentration (initiator exponent < 0.5). Initiator-dependent chain termination was significant along with the usual bimolecular mode of chain termination. The monomer exponent varied from about 1.0 to 1.5, depending on the nature of the solvent used. The nonidealities in this case were also analyzed.     

VISIBLE LIGHT PHOTOPOLYMERIZATION OF METHYL METHACRYLATE COINITIATED WITH TITANOCENE AND KETOCOUMARIN DYE*

The photosensitive system which can initiate methyl methacrylate with visible light was composedof compound 1 bis(η-5-cyclopentadienyl)-bis[2,6-difluoro-3-(1-H-pyrrolyl)phenyl]titanium (titanocene) andcompound 2 [(3,3'-carbonylbis(7-diethylamino coumarin)] (ketocoumarin dye). The high photosensitiveinitiating efficiency of this photosensitive system could be very promising for efficient system for laser (Ar~+488 nm) to plate and photocuring for thick coating and ink. The variation of UV-visible spectrum ofcompound 2 during irradiation indicates that photolysis of compound 2 is through its triplet state and it canbe quenched by O_2. The much quicker photobleaching of the photosensitive system suggests that there existscertain quick electron transfer reaction between compounds 1 and 2.     

PEB/MMA-AN悬浮接枝共聚反应机理

研究了乙烯-1-丁烯共聚物(PEB)弹性体与甲基丙烯酸甲酯(MMA)-丙烯腈(AN)悬浮接枝共聚反应行为及接枝共聚产物对SAN树脂增韧作用随反应时间的变化规律, 用凝胶渗透色谱法和傅里叶变换红外光谱法对接枝共聚产物进行了表征, 分析了接枝共聚反应机理, 推算了接枝链分子量. 结果表明, 体系首先发生链增长自由基向PEB转移终止形成非接枝共聚物(MAN_L)和PEB大分子自由基引发单体共聚形成接枝链(g-MAN)的反应, 接枝反应结束后体系发生明显的非接枝共聚形成非接枝共聚物(MAN_H)的反应; MAN_L的分子量低于g-MAN的分子量, 而g-MAN的分子量明显低于MAN_H的分子量; 在接枝共聚过程中发生已接枝和未接枝PEB断链并随机再接生成多嵌段共聚物的副反应; 在反应初期, 接枝链的AN单元含量接近于非接枝共聚物的AN单元含量, 在反应中后期前者远低于后者.     

Perylene as a visible light photoredox catalyst for photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization of MMA

Abstract

The organic photocatalyst, perylene, was used to mediate photoinduced electron transfer (PET) reversible addition-fragmentation chain transfer polymerization (RAFT) of methyl methhacrylate (MMA) under light irradiation in N,N-dimethylformamide (DMF) at 25°C with 4-cyanopentanoic acid dithiobenzoate (CPADB) as chain transfer agent (CTA). Kinetic studies confirmed that the polymerization obeyed the first order kinetic m'odel. The production of PMMAs with a good control of molecular weights (M_n,GPC) and narrow polymer molecular weight distribution (M_w/M_n) were obtained. It is found that well-controlled PET RAFT polymerization of MMA can be manipulated even with the amount of perylene decreasing to ppm level. No polymer was obtained in the absence of light irradiation, implying that the model of PET RAFT polymerization of MMA is an ideal light “on”-“off” switchable system. Furthermore, the speed of PET RAFT polymerization of MMA was also finely tunable by the external light irradiation intensity. The resultant PMMA macro-CTA was characterized by ¹H nuclear magnetic resonance spectrum (¹H NMR) and gel permeation chromatography (GPC). The accessibility of the high end group fidelity was further demonstrated by chain extension experiments.     

Polymerization of Methyl Methacrylate Using Acridone-Bromine Combination as the Photoinitiator

The photopolymerization of methyl methacrylate (MMA) in visible light was studied at 40°C using the acridone-bromine (acridone-Br₂) combination as the photoinitiator. The polymerization was found to proceed via a free radical mechanism, and the radical generation process was considered to follow an initial complexation reaction between monomer and each initiator component (acridone and Br₂), followed by further interaction between these two initiator-monomer complexes. Kinetic data indicated a lower-order dependence of R on initiator concentrations (initiator exponent < 0.5). Initiator-dependent chain termination was signifi-cant along with the usual bimolecular mode of chain termination. The monomer exponent varied from about 1.00 to 2.00, depending on the nature of solvents used. The nonidealities in this system were also analyzed.     

Polymerization of Methyl Methacrylate by Organometallic Compounds. V. Dark Stoichiometric and Polymerization Reactions between Trialkylaluminums and Methyl Methacrylate

The stoichiometric reaction products of the reaction of triethylaluminum and methyl methacrylate (MMA) derive from a different complex to that responsible for the photosensitized, radical polymerization. The stoichiometric products are the result of nucleophilic attack on the carbonyl group of MMA (1,2 addition). No 3,4 nucleophilic adducts are found and it is questioned whether the one product usually believed to be the result of conjugate (1,4) attack does so arise. The reactions have been followed, in situ, using 60 MHz NMR and mechanisms are discussed. The nucleophilic addition reactions do not develop into an anionic polymerization chain. The equilibrium constants governing MMA-triethylaluminium complex formation are such that the 1:1 complex, the precursor of radical polymerization, prevails overwhelmingly in MMA-rich mixtures and the precursor of stoichiometric, nucleophilic, addition reactions prevails in A1-rich mixtures. The validity of diagnostic tests for polymerization mechanism based on the nature of concomitant, low molecular weight products is discussed.

It is confirmed that triethylaluminium does not initiate MMA polymerization in the dark over the temperatures 233-333°K. We find diisobutylalumin-ium hydride inert, in dark or light, at 298 and 333°K. Triisobutylaluminium only initiates MMA when illuminated at 298°K, but at 333°K there is also a significant dark rate. Preliminary copolymerization experiments, devised to elucidate the mechanism of this dark polymerization, suggest that, as in the case of the photo-sensitized, triethylaluminium-initiated, radical polymerization, it proceeds from a 1:1 MMA: trialkylaluminium complex.