大分子阳离子光引发剂聚苯乙烯-碘鎓六氟锑酸盐的合成及其感光性能的研究

本文用羟基对甲苯磺酰氧基碘苯与聚苯乙烯进行亲电取代反应,得到大分子阳离子碘鎓盐光引发剂聚苯乙烯碘鎓-六氟锑酸盐(PS-I·SbF₆).用核磁共振仪、傅立叶红外光谱仪、凝胶渗透色谱仪、差示扫描量热仪、紫外分光光度仪对其进行了表征.与小分子碘鎓盐系光引发剂相比,PS-I·SbF₆的紫外最大吸收波长λ_max红移,在240-270 nm范围内有较强的吸收;固化成膜后其相对迁移率较小分子光引发剂有显著下降.初步研究了PS-I·SbF₆在环氧体系中的光固化性能,结果表明该体系有较好的光固化和后固化特性.     

大分子阳离子光引发剂聚苯乙烯-碘锚六氟锑酸盐的合成及其感光性能的研究

本文用羟基对甲苯磺酰氧基碘苯与聚苯乙烯进行亲电取代反应,得到大分子阳离子碘镥盐光引发剂聚苯乙烯碘镭一六氟锑酸盐（PS-I·SbF6）．用核磁共振仪、傅立叶红外光谱仪、凝胶渗透色谱仪、差示扫描量热仪、紫外分光光度仪对其进行了表征．与小分子碘镛盐系光引发剂相比,PS-I·SbF6的紫外最大吸收波长λmax红移,在240—270nm范围内有较强的吸收;固化成膜后其相对迁移率较小分子光引发剂有显著下降．初步研究了PS-I·SbF6在环氧体系中的光固化性能,结果表明该体系有较好的光固化和后固化特性．     

新型的香豆素染料/碘鎓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．大部分的光敏引发系统是由二个或三个组分组成,长波长的光引发聚合是通过以下两种不同过程得到实现［１］：（１）光敏系统直接吸收光并激发,（２）光引发系…     

五甲川菁染料的敏化作用及其在Gratzel型太阳能电池中的应用

采用新染料五甲川菁(Penta Methyl Cyanine)敏化TiO2纳米结构电极,UV-Vis吸收光谱和光电化学结果表明,使用该染料敏化使TiO2纳米结构电极吸收波长红移至可见光区和近红外区,可显著地提高TiO2纳米结构电极在可见光区的阳极光电流强度,明显改善光电转换效率.结合吸收光谱、电化学和光电化学结果初步讨论了敏化电极的光生电流的机理.     

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.     

还原态脒类LED光产碱剂的合成及性能研究

光产碱剂作为光固化材料体系中的关键组分,对光固化速率及固化材料性能有重要影响。本文以氧杂蒽酮作为生色团,脒类化合物DBN作为强碱基团,设计并合成了一种新型单组分氧杂蒽酮还原态脒类光产碱剂,并系统探究了其光物理和光化学行为。结果表明,氧杂蒽酮还原态脒类光产碱剂在345 nm区域具有较强吸收,光解后释放的强碱DBN可有效引发巯基-环氧体系聚合。与商品化苄基还原态脒类光产碱剂相比,氧杂蒽酮生色团的引入使光产碱剂的吸收波长红移,能更好地匹配365 nm LED光源;与离子型硫杂蒽酮光产碱剂相比,氧杂蒽酮还原态脒类光产碱剂在光解过程中不产生二氧化碳,且催化效率更高,具有良好的应用前景。     

三甲川菁染料敏化TiO2纳米结构电极的光电化学

研究了三甲川菁染料敏化ＴｉＯ２ 纳米结构电极的光电化学行为．结果表明,使用该染料敏化可显著提高ＴｉＯ２ 纳米结构电极的光电流,使电极的吸收波长红移至可见光区,光电转换效率得到明显改善,ＩＰＣＥ值最高可达１２－１ ％ ．     

可见光敏引发体系荧光黄双二苯基碘钅翁盐的研究

通过计算呫吨染料与二苯基碘钅翁盐反应的电子转移参数, 发现荧光黄与二苯基碘钅翁盐反应的热力学驱动力最大, 证明了实现光敏化方式是电子转移反应. 通过对引发体系吸收光谱的研究, 考察了不同价键结构、溶剂效应及引发剂浓度对引发体系吸收光谱的影响, 证实了与C-6位酚氧离子相结合的离子种类很大程度上决定了染料敏化体系的吸收峰强度及峰形状, 溶剂极性增大, 吸收光谱红移; 溶剂极性减小, 其吸收光谱蓝移. 在非极性溶剂中, 引发剂浓度越高, 其解离度越大, 引发剂更多地以自由离子形式存在.     

Aza-BODIPY荧光染料的合成、表征及性能研究

aza-BODIPY荧光染料是近10年发展起来并受到广泛关注的一类新型荧光化合物,它极有可能发展成可应用于光动力学治疗的光敏剂.本工作合成了5个aza-BODIPY 1a～1e,用IR,NMR,MS和元素分析对它们进行了表征.研究了它们的紫外吸收光谱与荧光发射光谱,结果表明1a～1e具有较高的摩尔吸光系数,在aza-BODIPY母环的3,5位或1,7位的苯环4位有供电子取代基时能使化合物的最大紫外吸收波长和荧光发射波长红移.测试了1a～1d的循环伏安曲线,根据各化合物的氧化还原电位讨论了它们的结构稳定性.     

聚合物分散液晶(PDLC)材料的光聚合反应

以Ar+激光器为光源, 采用虎红、 N-苯基甘氨酸、二季戊四醇羟基五丙烯酸酯和乙烯基吡咯烷酮分别作为光引发剂、共引发剂、预聚物和稀释剂, 与液晶材料TEB30A结合, 通过光聚合反应, 制备了聚合物分散液晶(PDLC), 用紫外光谱和荧光光谱对其反应机理进行了分析. 实验结果表明, PDLC是通过光引发剂吸收光子能量后与共引发剂相互作用, 形成自由基中间体并引发聚合反应, 使预聚物与液晶产生相分离形成的.     

Photoinduced and thermally induced cationic polymerizations using S,S‐dialkyl‐S‐(3,5‐dimethylhydroxyphenyl)sulfonium salts

A study of the photoinitiated and thermally initiated cationic polymerizations of several monomer systems with S,S‐dialkyl‐S‐(3,5‐dimethylhydroxyphenyl)sulfonium salt (HPS) photoinitiators bearing different lengths of alkyl chains on the positively charged sulfur atom has been conducted. HPS photoinitiators are capable of photoinitiating the cationic polymerization of a wide variety of epoxy and vinyl ether monomers directly on irradiation with short‐wavelength UV light. Aryl ketone photosensitizers are effective in extending the spectral response of these photoinitiators into the long‐wavelength UV region. Kinetic studies with real‐time infrared spectroscopy show that HPS photoinitiators exhibit good efficiency in the polymerization of epoxide and vinyl ether monomers. Comparative studies also demonstrate that S,S‐dimethyl‐S‐(3,5‐dimethyl‐2‐hydroxyphenyl)sulfonium salts are more active photoinitiators than their isomeric S,S‐dimethyl‐S‐(3,5‐dimethyl‐4‐hydroxyphenyl)sulfonium salt counterparts. Both types of HPS photoinitiators display reversible photolysis as a result of facile termination reactions that take place between the growing chains ends with the photogenerated sulfur ylides. Preliminary studies have shown that HPS photoinitiators can also be employed as thermal initiators for the cationic ring‐opening polymerization of epoxides at moderate temperatures. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2570–2587, 2003     

Curcumin: A naturally occurring long‐wavelength photosensitizer for diaryliodonium salts

Curcumin, a naturally occurring, intensely yellow dye extracted from the spice turmeric, is an efficient photosensitizer for diaryliodonium salt photoinitiators at wavelengths ranging from 340 to 535 nm. With curcumin as a photosensitizer, it is possible to carry out the cationic photopolymerization of a wide variety of epoxide, oxetane, and vinyl monomers with long‐wavelength UV and visible light. An example of the photopolymerization of an epoxide monomer with ambient solar irradiation is provided. Several other curcumin analogues were synthesized, and their use as photosensitizers is examined. With such photosensitizers, the range of spectral sensitivity can be extended well into the visible region of the electromagnetic spectrum. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5217–5231, 2005     

Phenothiazine photosensitizers for onium salt photoinitiated cationic polymerization

Phenothiazine compounds bearing a wide range of different substituents are excellent photosensitizers for onium salt cationic photoinitiators. These photosensitizers are generally operative in the mid‐ and long‐range regions of the UV spectrum and are especially useful for enhancing the rate of photoinitiated cationic polymerization carried out utilizing both filtered and broadband UV emission sources. In this article, the syntheses of several different substituted phenothiazines are described and the ability of these compounds to photosensitize the photolysis of different onium salt photoinitiators is evaluated. Attempts were made to correlate the structure and spectral characteristics of the phenothiazines with their efficiency of photosensitization in the cationic photopolymerizations of several typical epoxide and vinyl ether monomers. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1187–1197, 2001     

Light‐Harvesting Organic Photoinitiators of Polymerization

Two new photoinitiators with unprecedented light absorption properties are proposed on the basis of a suitable truxene skeleton where several UV photoinitiators PI units such as benzophenone and thioxanthone are introduced at the periphery and whose molecular orbitals MO can be coupled with those of the PI units: a red‐shifted absorption and a strong increase of the molecular extinction coefficients (by a ≈ 20–1000 fold factor) are found. These compounds are highly efficient light‐harvesting photoinitiators. The scope and practicality of these photoinitiators of polymerization can be dramatically expanded, that is, both radical and cationic polymerization processes are accessible upon very soft irradiation conditions (halogen lamp, LED…︁) thanks to the unique light absorption properties of the new proposed structures.     

Photopolymerization of hybrid monomers: Part I: Comparison of the performance of selected photoinitiators in cationic and free-radical polymerization of hybrid monomers

Photopolymerization of the hybrid monomers: 3,4-epoxycyclohexylmethyl methacrylate (Cyclomer M100) and 2-(2-vinyloxyethoxy)ethyl acrylate (VEEA) was studied by Fluorescence Probe Technique (FPT). Kinetics of cationic and free-radical photopolymerization of the hybrid monomers in the presence of the same molar concentration of various photoinitiators was compared, using UV LEDs as the curing light source. The performance of the following photoinitiators was tested in the cationic photopolymerization: Sylanto 7M-S, Sylanto 7M-P, Speedcure 938, Irgacure 250, HIP, Esacure 1187, and the following photoinitiators were used to induce free radical photopolymerization: Irgacure 184, Irgacure 127, Irgacure 651, Irgacure 907, Irgacure 819 and Speedcure TPO. It was found that, among the cationic photoinitiators, Sylanto 7M-S and Sylanto 7M-P are the most effective photoinitiators of the cationic polymerization for use with 320 nm and 365 nm UV LEDs, while Irgacure 819 and Speedcure TPO perform best in free radical photopolymerization of the hybrid monomers. Some structural factors and parameters affecting the photoinitiators performance are discussed.     

Synthesis and photoactivity of novel 5‐arylthianthrenium salt cationic photoinitiators

5‐Arylthianthrenium salts are a class of efficient triarylsulfonium salt photoinitiators for cationic polymerization. These compounds were prepared by a simple, straightforward, versatile, and high yield route. The new photoinitiators were characterized by standard analytical and spectroscopic techniques, and their activity as cationic photoinitiators was compared with related triarylsulfonium salts of similar structures using Fourier transform real‐time infrared spectroscopy. Through the use of electron‐transfer photosensitizers, the response of these photoinitiators can be readily spectrally broadened into the long‐wavelength UV–visible regions of the spectrum. The results obtained suggest that 5‐arylthianthrenium salts are potential replacements for now available triarysulfonium salt photoinitiators in many applications. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3465–3480, 2002     

Organic dye-based photoinitiating systems for visible-light-induced photopolymerization

Even though many organic dyes have been reported as photoinitiators/photosensitizers for free radical polymerization in the literature, the design and development of novel photoinitiating systems based on organic dyes adaptable for visible light irradiation, for example, 405 nm LED and sunlight still remains challenging. Recently, major achievements in the development of high-performance photoinitiating systems based on organic dyes as light-harvesting compounds and their uses as photoinitiators for photopolymerization under visible-light irradiation have clearly emerged, giving rise to abundant literature. In this review, an overview of the recently synthesized chromophores belonging to various families of organic dyes and used as photoinitiators of polymerization during the 2018–2021 period are presented and classified. Recent works have resulted in the development of new chromophores exhibiting remarkable visible light absorption properties and excellent photoinitiation abilities upon irradiation with LEDs and/or sunlight in free radical photopolymerization processes. These developments notably indicate that sunlight has the advantages of being a cheap, unlimited, broad emission spectrum, and energy-saving light source capable to be an efficient substitute to artificial light sources. The newly developed dye-based photoinitiating systems designed to initiate visible-light-induced photopolymerization processes are likely to expand the scope of application of photopolymerization in modern sciences and technologies.     

Wavelength Flexibility in Photoinitiated Cationic Polymerization

The spectral sensitivity of onium salt photoinitiators in cationic polymerization can be tuned from the short wavelength region of the UV spectrum to wavelengths up to the visible region by using direct and indirect activation, respectively. Indirect activation is based on the electron transfer reactions between onium salts and free radical photoinitiators, appropriate sensitizers and compounds capable of forming charge transfer complexes. Bisacylphosphine oxides, dimanganese decacarbonyl in conjunction with alkyl halides and titanocene type photoinitiators such as Irgacure 784 were shown to be useful free radical promoters providing the possibility of performing cationic polymerization in the long wavelength and visible region. The synthetic routes to prepare block copolymers by using electron transfer photosensitization and free radical promoted cationic polymerization are also described.     

Cationic Polymerization: New Developments and Applications

The chemistry and technology of photoinitiated cationic polymerization is a rapidly advancing field of investigation. This article reports on recent developments made in our laboratory in the development of new photoinitiators and photosensitizers. S,S-Dialkyl-S-phenacylsulfonium salts have been prepared using a new, highly efficient and cost-effective synthetic method and their use in the polymerization of various monomer systems studied. Also described is the development of alkoxyanthracene photosensitizers that may be employed to broaden the spectral sensitivity of various onium salt photoinitiators including the new S,S-dialkyl-S-phenacylsulfonium salts. A marked acceleration of the rate of the ring-opening polymerization of epoxide monomers was achieved using these photosensitizers. This article concludes with a brief discussion of the use of photoinitiated cationic polymerizations in such typical applications as can coatings, silicone release coatings and in stereolithography.     

Supramolecular diaryliodonium salt‐crown ether complexes as cationic photoinitiators

Diaryliodonium salts spontaneously form crystalline 1:1 supramolecular complexes at room temperature in good to excellent yields with 18‐crown‐6 ether and its cyclohexano‐ and benzo‐substituted analogs. The complexes were characterized using IR, UV, MS, ¹H, and ¹³C‐NMR spectroscopy and by single crystal X‐ray crystallography. The analytical data obtained were consistent with a structure in which the positively charged iodine atom of diaryliodonium cation is positioned above and over the center of the crown ether ring with the positively charged iodine atom coordinated to the crown ether oxygen atoms. The diaryliodonium salt‐crown ether complexes are photosensitive and were used to carry out the photoinitiated cationic polymerizations of a number of mono‐ and difunctional monomers. During irradiation with UV light, the supramolecular complexes undergo photolysis with the generation of a Brønsted acid and with the concomitant release of the crown ether. When used as photoinitiators, the crown ether that is released markedly influences the kinetics of the subsequent cationic polymerization of the monomer. Further studies demonstrated that the photolysis of diaryliodonium salt‐crown ether supramolecular complexes can be photosensitized using typical‐electron transfer photosensitizers. Free radical‐promoted photosensitization using typical unimolecular free radical photoinitiators such as 2,2‐dimethoxy‐2‐phenylacetophenone also takes place readily. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013