快速光固化用阳离子光引发剂研究进展

介绍了阳离子型光引发剂的引发原理,综述了芳香重氮盐,有机铝络合物/硅烷体系,茂铁盐化合物,二芳基碘鎓盐和三芳基硫鎓盐及其他新型阳离子光引发剂的开发及其改性研究进展。     

碘鎓盐/胺光引发聚合体系的初级反应研究

碘鎓盐/胺复合体系,用作自由基光敏聚合的引发剂具有良好的效果,但是关于碘鎓盐和胺相互作用产生有引发活性的自由基的光化学反应机制尚不清楚。Ptitsyna曾研究了二苯基碘鎓盐和三苯基膦的光化学反应,认为首先发生鎓盐的裂解反应,接着进行芳基化作用,生成主要产物四苯基鏻和碘苯。而二芳基碘鎓盐和脂肪胺的热化学反应,则得到的主要胺类产物为原始胺的盐,芳基化产物很少。 本工作以二苯基碘鎓盐(DPIOC)/三乙胺(TEA)为例子,研究了这类化合物的光化学反应。采用高压汞灯为光源,并滤去<300nm的光,介质为CH_3CN/H_2O(14:1,V/V)混合溶剂,反应在N_2下进行,温度为30℃。关于碘鎓盐和叔胺分子间的相互作用,从     

一种新型三芳基硫鎓盐光引发剂的合成

以二苯醚与等摩尔的对甲氧基苯甲酰氯为原料合成了4-甲氧基-4’-苯氧基二苯甲酮,4-甲氧基-4’-苯氧基二苯甲酮与二苯亚砜在P2O5和CH3SO3H介质中,80℃下反应24h,合成了一种新型的三芳基硫鎓盐,对这种新型三芳基硫鎓盐的结构用^1HNMR及^13C NMR进行了分析表征,并考察了它的光引发性能,发现它是一种很好的阳离子光引发剂。     

鎓盐类阳离子聚合光引发剂的研究进展

碘鎓盐和硫鎓盐是最重要的和应用最广泛的阳离子聚合光引发剂。本文介绍了几种典型的碘鎓盐和硫鎓盐及其引发机理,并就碘鎓盐和硫鎓盐在增加光引发剂的光敏性、增加光引发剂在光引发阳离子聚合体系中的组分相容性以及在阳离子光引发剂中引入自由基等方面的发展状况进行了综述。     

9-乙烯基蒽/二苯基碘鎓盐体系敏化甲基丙烯酸甲酯光聚合

通过对9-乙烯基蒽单组分及其与氯化二苯基碘鎓盐(DPIOC)组成的双组分光敏体系引发甲基丙烯酸甲酯光聚合的研究,发现DPIOC的加入明显增大了9-乙烯基蒽光引发聚合速度.它们在引发MMA光聚合的同时,也参与聚合反应而自身进入聚合物链中.     

二烷基(4-羟基苯基)硫鎓盐的电荷转移络合物及其敏化光降解

二烷基(4-羟基苯基)硫鎓盐作为一类新型的光引发剂由于其合成方法简便以及具较宽的光谱范围(可延伸至300nm)。因而近年来颇受重视。由于该引发剂在光照激发后生成了共振一稳定的内鎓盐(Ylide)结构和质子酸。如下式:     

铜催化环状二芳基碘鎓盐和对甲苯磺酰腙发生开环反应制备含氮联芳基化合物

由于二芳基碘鎓盐具有非爆炸性、无毒且稳定的性质,通常用作多种亲核试剂的芳基化试剂。介绍了铜催化环状二芳基碘鎓盐和对甲苯磺酰腙的开环反应。该反应条件温和,产率高。     

专利介绍

1 碘盐作为先引发剂及其制成的光固化涂料 JP11-279,212 碘盐(碘鎓盐)用作光聚合引发剂,具有优良的可溶解性,低着色性(浅色性)和低毒性,它可以用于光固化的涂料,粘结剂,光刻胶或油墨等。例如:苯氧基乙酸甲酯和亚碘酰苯的醋酸酯反应产物,可制得碘鎓盐     

二苯亚砜与芳香化合物缩合制备芳基取代硫鎓盐的研究

以多聚磷酸为脱水剂,二苯亚砜分别与二苯硫醚,二苯基醚和联苯反应制备了三种芳取代三苯基硫鎓盐。该反应条件温和,反应温度为40～50℃,时间为6～8h。其中4-(苯硫基)三苯基硫鎓六氟磷酸盐的收率为87．6％。对三种硫鎓盐的紫外光谱和红外光谱进行了详细的研究。三种硫鎓盐对环氧树脂具有良好的固化性能。     

稠环化合物敏化硫鎓盐引发阳离子光聚合的研究

合成了三芳基硫鎓六氟磷酸盐光引发剂。研究了不同稠环化合物对硫鎓盐引发阳离子光聚合速度的影响，用光致电子转移(光氧化还原)理论解释了这些稠环化合物的光敏机理。     

香豆素酮类化合物的瞬态研究——Ⅲ.香豆素酮和碘鎓盐间的电子转移

本工作采用激光闪光光解法对香豆素酮类化合物敏化碘鎓盐化合物问题进行了研究。结果表明:碘鎓盐化合物能通过电子转移机理猝灭香豆素酮的激发三重态。工作中还用甲基紫精(PQ~(2+))为模型化物,观察到它也能使香豆素酮的三重态猝灭,同时可看到在位于610nm处的PQ~+生成。这些结果说明,在发生电子转移的反应中香豆素酮是电子给体,按Weller公式的计算结果也表明它们之间可发生电子转移反应。     

Photoinitiated cationic polymerization of urethane vinyl ether crystalline monomers

Photoinitiated cationic polymerization of crystalline monomers based on urethane vinyl ether has been investigated by means of differential photocalorimetry (DPC). The crystalline monomers in the melt state polymerized rapidly by exposure to UV light in the presence of a cationic photoinitiator such as an iodonium salt, sulfonium salt or iron arene salt. The kinetics of the cationic photopolymerization process were studied by following k_p[M⁺] as a function of conversion. High conversions, of around 90 %, were obtained for most of the systems investigated. The efficiency of the cationic photoinitiators in initiating the polymerization of the vinyl ether monomers was in the order: iodonium salt > iron arene salt > sulfonium salt. Monomers modified with different saturated alcohols had different activities in photopolymerization, although they all carry the same functional group, i.e. vinyl ether. Copyright © 2005 Society of Chemical Industry     

Novel sulfonium salts as thermal and photoinitiators for epoxide and acrylate polymerizations

Novel sulfonium salts, 1‐naphthylmethyl‐, cinnamyl‐, 9‐fluorenyl tetramethylene sulfonium hexafluoroantimonates, and dimethylsulfonium hexafluoroantimonates, were synthesized by the reaction of tetrahydrothiophene and dimethylsulfide with the corresponding bromides or chloride, followed by anion exchange with KSbF₆. These sulfonium salts polymerized epoxy monomers at a temperature lower than previously reported for benzyltetramethylenesulfonium hexafluoroantimonate. They initiated radical photopolymerization as well as cationic polymerization. The photopolymerization was accelerated by the addition of aromatic compounds such as p‐methoxyphenol, 4‐methoxy‐1‐naphthol, 2‐ethyl‐9,10‐dimethoxyanthracene, N‐ethylcarbazole, and phenothiazine as photosensitizers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 589–597, 2004     

Photoinitiated cationic ring-opening polymerization of a cyclosiloxane

Hexamethylcyclotrisiloxane was found to undergo photoinitiated cationic ring-opening polymerization in solution and bulk, upon exposure to UV radiation, in the presence of either sulfonium or iodonium salts or an iminosulfonate derivative. Glass transition temperatures were below − 100 °C. Molecular weights, determined by size exclusion chromatography relative to polystyrene standards, increased with photolysis lamp intensity. Use of an iodonium photoinitiator afforded poly(dimethylsiloxane) with Mn = 172,000. Polymerization of hexamethylcyclotrisiloxane was accompanied by a small increase in volume (3 – 4%). Received: 12 September 1996/Revised: 29 October 1996/Accepted: 1 November 1996     

Photoinitiation of cationic polymerization by visible light activated titanocene in the presence of onium salts

Summary A visible light photoinitiating system for cationic polymerization of cyclic ethers such as cyclohexene oxide (CHO) and vinyl monomers such as n-butyl vinyl ether (BVE) and N-vinyl carbazole (NVC) has been developed, using a fluorinated titanocene free radical photoinitiator, Irgacure 784, together with an onium salt, such as diphenyl iodonium hexafluoro antimonate and N-ethoxy-2-methyl-pyridinium hexafluoro-antimonate. Based on the reported photochemistry of fluorinated titanocenes, a mechanism for generating cationic species is proposed based on electron transfer between photoproducts of titanocene and onium salt. Evidence against the incorporation of an aromatic titanocene moiety in the resulting polymers is presented. Inhibition by a specific proton scavenger suggests that protons may initiate the polymerization. Received: 26 April 2001/Revised version: 6 June 2001/Accepted: 6 June 2001     

Influence of different initiators on the adhesion properties of photopolymerized epoxides on gold and silicon

Photocuring of epoxides proceeds by a cationic mechanism. The required photoinitiators are iodonium or sulfonium salts with non-nucleophilic anions. The influence of different photoinitiators on the adhesion properties of both a rigid and a soft epoxide is examined. Depending on the substrates to be joined, different decomposition products of the initiators are concentrated in the interphase. This accumulation of decomposition products in the interphase leads to a decreased adhesion. On gold surfaces the sulfur of sulfonium salts is concentrated as expected. But surprisingly the iodine of the iodonium salts is also concentrated on gold. It could be shown by immobilization experiments that organic iodine compounds with the iodine in any oxidation state reacted with gold surfaces. Due to this reaction iodide anions are formed. On silicon surfaces the fluorine of the anions PF₆ ^- and SbF₆ ^- is concentrated due to the high affinity of silicon for fluorine. The iodonium salt with [B(C₆F₅)₄]anion contains no fluorine able to react with the silicon. Therefore, the fluorine cannot be concentrated in the interphase and the joints prepared with the soft epoxide containing this initiator have a higher shear strength compared to adhesives with conventional anions.     

Efficient visible photoinitiator with high‐spectrum stability in an acid medium for free‐radical and free‐radical‐promoted cationic photopolymerization based on erythrosine B derivatives

Three dye‐linked photoinitiators with excellent spectral stability in an acid medium were synthesized by the covalent bonding of a coinitiator (tertiary amine) and a benzoyl group or two coinitiators to the phenolic and carboxyl group position of erythrosine B. The combination of the iodonium salt and free tertiary amino used to initiate the free‐radical/cationic visible photopolymerization was investigated to acquire the relationship between the structure and performance. The photoinitiating ability of the derivative with the phenolic position bearing a coinitiator was poorer than of the derivative with the carboxyl group bearing one because of the strong back electron transfer of the former. For the derivative with a linked coinitiator on the carboxyl position, the proximity effect between the sensitizer and the coinitiator moiety resulted in an excellent photoinitiating ability for radical/cationic polymerization; this suggested its potential for application. Although radical/cationic photopolymerization could be initiated by the derivative/coinitiator/iodonium salt, the different component ratios between them had different effects on these two polymerizations; this provided useful information for the design of effective photoinitiators for different polymerizations. On the basis of the fluorescence quenching and photopolymerization results, a corresponding synergistic mechanism was proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43035.     

Sulfonium polymers derived from Ar-vinylbenzyl chloride. I. Exploratory study of the preparation and properties of the monomers and polymers

Although sulfonium salts are well known, polymeric sulfonium salts seldom have been mentioned in the chemical literature. This paper describes exploratory work in the preparation of various sulfonium monomers and polymers from ar-vinylbenzyl chlorides (ortho and para isomers). These chlorides—particularly the para isomer—reacted readily with 2,2′-thiodiethanol and water to yield the corresponding ar-vinylbenzyl sulfonium chloride monomers in aqueous solution. The odorless, reactive monomer mixture polymerized readily with persulfate or hydroperoxide catalysts; however, polymerization could be inhibited with cupric salts. Copolymerization with trimethyl(ar-vinylbenzyl)ammonium chloride was random. In copolymerization with acrylamide or acrylonitrile, the sulfonium monomer was more reactive. Analogous sulfonium monomers were made by reaction of ar-vinylbenzyl chlorides with various sulfides. In general, all the sulfonium monomers yielded homopolymers which were fairly stable in aqueous solution in the absence of strongly nucleophilic agents which would attack the sulfonium groups. However, when dried at room temperature the polymers would crosslink; and when heated, the polymers became hydrophobic also. Scrambling of the sulfonium group substituents during drying, and nucleophilic displacement reactions by chloride ion during heating were likely explanations. The high cationic charge on the polymers made them substantive to cellulose fibers. This property, when coupled with high nucleophilic reactivity of the sulfonium groups with the carboxylate sites of the pulp or other anionic counterious during drying and heating, made the polymers very effective as beater additives for imparting wet strength to paper.