光致阳离子聚合单体的进展

光致阳离子聚合体系具有聚合速度快、不受氧干扰以及对水不敏感等优点,为了适应光致阳离子聚合体系的发展,可进行光致阳离子聚合的单体和光致阳离子引发剂的研究越来越受到人们的重视,本文就其中的一方面可进行光致阳离子聚合的单体进行了综述。     

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。     

光引发阳离子聚合及其在环氧树脂固化研究中的进展

从光引发阳离子聚合的特点、常见阳离子型光敏引发剂及其引发聚合机理、光引发环氧树脂阳离子聚合体系及发展前景等几个方面进行了简要概述。     

UV阳离子固化及研究进展

UV阳离子固化不被氧气阻聚,只抑制自由基聚合;开环聚合时体积收缩小,涂层附着力强;固化反应不易终止,适用于厚膜和色漆的光固化。日本正在进行阳离子体系的相关课题研究;北美的环氧-阳离子固化产品已占辐射固化产品的5％;我国对UV固化的研究起步较晚。目前,阳离子固化体系发展的阻碍主要在于阳离子光敏引发剂价格昂贵,若加量2％,则引发剂成本为8万元/t。解决问题的关键是优化现有光引发剂生产工艺,降低生产成本,研究同系物中价廉的引发剂,或开发其他引发剂或引发体系;开发新单体,组成阳离子-自由基共引发体系,也是一个值得注意的发展方向。本文还介绍了UV阳离子固化体系及其固化机理。     

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六氟磷酸盐光引发剂。研究了不同稠环化合物对硫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。     

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。     

紫外阳离子光引发剂及其发展动态

阳离子型光引发聚合是一种快速、高效、低能耗和低污染的聚合方式。着重介绍阳离子光引发剂的主要种类、各自的特点及其光引发机理,简述阳离子光引发剂在涂料中的应用和发展,并对今后的研究方向进行了展望。     

阳离子丙烯酸系聚合物乳液的合成和应用

综述了合成阳离子丙烯酸系聚合物乳液的乳化剂、引发剂及单体体系和聚合方法,介绍了阳离子乳液的性质和应用。     

光固化涂料用光引发剂的进展

综述了光固化涂料用引发剂的反应机理，介绍了自由基和阳离子光引发聚合体系用引发剂的类型及其典型品种的主要性质、特点和应用，指出了近年来国内外光引发剂的发展方向。     

阳离子聚合光引发剂及其阳离子反应机理

综述了阳离子聚合光引发剂的种类、制备和应用，介绍了它们的光分解和由此引发的光引发阳离子聚合反应机理。     

阳离子光引发剂研究进展

阳离子型光引发剂是一类新型的紫外光固化材料的引发剂。本文介绍了阳离子光引发剂的主要种类及各自的特点 ,讨论了其光引发机理 ,并简述了阳离子光引发剂的的发展概况和主要用途。     

The synthesis and characterization of cationic photoinitiators bearing two and three photoactive triarylsulfonium groups in the same molecule

Summary A novel series of photoinitiators for cationic polymerization have been prepared which bear two and three photoactive triarylsulfonium groups in the same molecule. These compounds have been fully characterized by means of their UV and C-NMR spectra and liquid chromatography as well as by their elemental analyses. The multifunctional triarylsulfonium salts have been compared among themselves and against monofunctional triarylsulfonium salts in the photoinitiated cationic polymerization of dl-limonene dioxide.     

Photochemically initiated free radical promoted living cationic polymerization of isobutyl vinyl ether

A new photoinitiating system for living cationic polymerization of vinyl ethers such as isobutyl vinyl ether (IBVE) has been reported. The photoinitiating system comprises free radical photoinitiators such as 2,2-dimethoxy-2-phenyl acetophenone (DMPA), benzophenone or thioxanthone, together with an onium salt, such as diphenyliodonium chloride and zinc bromide. In the first step, photochemically generated free radicals are oxidized to the corresponding carbocations which subsequently react with vinyl ether monomer to yield an adduct. In the presence of zinc salt, this adduct initiates living cationic polymerization of IBVE.     

(η6‐N‐alkylcarbazole) (η5‐cyclopentadienyl) iron hexafluorophosphate salts in photoinitiated and thermal epoxy polymerization

(η6‐Carbazole)(η5‐cyclopentadienyl) iron hexafluorophosphate salts (CFS PF₆) are capable of photoinitiating cationic polymerization of epoxy monomers directly upon irradiation with long‐wavelength UV light. To improve the solubility of CFS ferrocenium salts in epoxides, two CFS photoinitiators have been prepared: [cyclopentadiene‐Fe‐N‐buylcarbazole] hexafluorophosphate (C4‐CFS PF₆) and [cyclopentadiene‐Fe‐N‐octylcarbazole] hexafluorophosphate (C8‐CFS PF₆), bearing C4 and C8 alkyl chains, respectively, on the nitrogen atom. Studies with real‐time infrared spectroscopy have shown that C4‐CFS and C8‐CFS photoinitiators exhibit high efficiency in polymerization of 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexane carboxylate (ERL‐4221) epoxy monomer, but lower efficiency in polymerization of di(2,3‐epoxypropyl)‐3,4‐epoxy‐1,2‐cyclohexanedioate (TDE‐85) epoxy monomer. Benzoyl peroxide (BPO) sensitizer was very effective in improving the photoinitiating activities of CFS in polymerization of both ERL‐4221 and TDE‐85. DSC studies have shown that C4‐CFS and C8‐CFS photoinitiators can also be employed as thermal initiators for the cationic ring‐opening polymerization of epoxides at moderate temperatures. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Possibilities for photoimaging using onium salts

The recent discovery that the photolysis of certain onium salts produces strong Brønsted acids presents a unique opportunity to design novel photoimaging systems based on these materials. For example, when used as photoinitiators, they can induce the negative image wise cationic polymerization of multifunctional epoxides, vinyl ethers, and lactones. Alternatively, they may be used to catalyze the degradation of hydrolytically sensitive polymers to give positive photoresists. The ability of still other onium salts to generate radical species as well as strong acids has been exploited to develop photoimaging processes which have no parallel in present photoresist technology. The processes consist of simultaneous radical polymerization and acid-induced cationic polymerization. Finally, the recent observation that the onium salts can be dye-sensitized allows them to be responsive to both the ultraviolet and visible regions of the spectrum and to be used with many commercial optical imaging systems.     

改善鎓盐类阳离子光引发剂光敏性的研究概况

鎓盐类阳离子型光引发剂是一类新型高效的紫外光固化引发剂,它在紫外光固化领域中有着十分重要的地位。重点介绍了增强鎓盐光敏性的方法及相关机理,简单介绍了鎓盐类阳离子光引发剂的特点和研究进展。     

［环戊二烯-铁-二苯甲烷］六氟磷酸盐的光催化研究

芳茂铁盐是一类有效的用于环氧聚合的光引发剂。通过二茂铁和二苯甲烷的配体交换反应,制备了新型的芳茂铁盐［环戊二烯-铁-二苯甲烷］六氟磷酸盐（［Cp-Fe-Bp］⁺PF₆^-）。研究了其紫外－可见吸收性能和光解,发现［Cp-Fe-Bp］⁺PF₆^-）由d-d跃迁产生的在300 nm以上的吸收使其适合长波紫外光源。通过实时红外研究了［Cp-Fe-Bp］⁺PF₆^-）的光引发活性,表明能有效地引发3,4-环氧基环己基甲酸-3′4′-环氧基环己基甲酯（ERL-4221）开环聚合,过氧化苯甲酰能使其光引发活性显著提高。