3D打印用长波紫外光固化树脂的制备

通过优化引发剂的种类和用量,得到一系列阳离子和自由基混杂体系光固化树脂,并用旋转流变仪和SLA型3D打印机进行长波紫外光固化和3D打印成型。结果表明:与芳基鎓盐类阳离子光引发剂PAG202相比,芳茂铁盐类阳离子光引发剂261具有长波紫外光固化的适应性,而光敏增感剂PAS-50对光引发剂261敏化显著,在长波紫外光下光引发剂261/PAS-50体系能快速引发树脂固化。最佳配方时,固化树脂的弯曲模量高于国内外同类树脂的,且具有较低的固化收缩率。     

紫外光固化粉末涂料

阐述了紫外光固化粉末涂料的各种优点及紫外光固化粉末涂料光活性预聚物、光引发剂等配方组成,介绍了紫外光固化粉末涂料制备施工方法、紫外光固化设备及其应用发展趋势。     

激光固化快速成型技术中环氧树脂/碘鎓盐的应用

合成了三种不同二苯基碘鎓盐作为阳离子光引发剂应用于激光固化快速戍型环氧树脂中。结果表明,碘鎓盐阴离子部分的结构对环氧树脂的光固化速度有很大影响;碘鎓盐的质量分数以3％～5％为宜;光敏剂的加入可提高光引发效率;激光功率和光束扫描速度等参数对固化过程有较大的影响;阳离子光引发剂引发固化体系的收缩率比自由基光引发剂的要小。     

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。     

常用光引发剂在紫外光固化涂料中的应用研究

针对紫外光固化体系,研究了常用光引发剂在紫外光固化涂料中的应用。讨论了常用光引发剂的用量及其对亮光体系、亚光体系和色漆体系固化性能的影响。得出在紫外光固化涂料中选择引发剂的规律。     

紫外光固化光引发剂研究进展

介绍了紫外光固化体系中光引发剂的反应机理 ,着重介绍了自由基型和离子型光引发剂的引发机理、种类、分子结构及各自优缺点。     

浅析水性光引发剂在紫外光固化涂料中的发展前景和应用

随着绿色发展理念深入人心,社会发展方式加快转变,紫外光固化技术做为一种绿色环保的技术,受到前所未有的关注。而水性光引发剂由于良好的引发光聚合反应的能力和优良的水溶性逐步成为紫外光固化涂料研究的热点。本文以水性光引发剂在紫外光固化涂料中的发展和应用研究为中心,首先分析水性光引发剂的应用优势以及对紫外光固化涂料的重要意义,其次研究水性光引发剂在紫外光固化涂料中的应用,最后明确紫外光固化涂料中水性光引发剂的发展与研究方向,为水性光引发剂的深入研究和拓展紫外光固化涂料应用领域奠定扎实理论基础。     

紫外光固化涂料用光引发剂的研究进展

紫外光固化涂料是新一代绿色环保化工产品,由于其性能优良,近几十年获得了快速发展,光引发剂作为紫外光固化涂料的重要组成部分,也随之获得迅猛发展,本文综述了光固化涂料用引发剂的反应机理,介绍了光引发剂的分类及其典型化合物的主要性能、特点和应用;指出了光引发剂的发展方向。     

光引发剂及其在紫外光固化粘合剂中的应用研究进展

光引发剂在光固化领域里有着非常重要的作用。随着各种光引发剂的发展,带动了紫外光固化粘合剂的一系列同步发展。综述了光引发剂以及它们在紫外光固化粘合剂中的应用研究进展。     

紫外光固化涂料用光引发剂的应用研究进展

光引发剂作为紫外光固化体系中重要的组成部分,对产品的最终性能具有决定性作用。随着紫外光固化技术的快速发展,必须寻找与之相匹配、性能优异的新型光引发剂。针对现有光引发剂存在氧阻聚及价格方面的缺陷,科研人员开发出各种新型光引发剂。本文在总结传统的商业化光引发剂的分类、特点、合成方法的基础上,对其在紫外光固化体系中的光固化效率进行了讨论。     

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.     

The synthesis of novel,visible-wavelength oxidizable polymerization sensitizers based on the 5,12-dihydroquinoxalino[2,3-b]pyridopyrazine skeleton

Novel dyes based on the 5,12-dihydroquinoxalino[2,3-b]pyridopyrazine skeleton were synthesized and subsequently characterized using ¹H NMR. Their electrochemical and spectral properties, such as absorption and emission spectra, quantum yield of fluorescence, and quantum yield of singlet oxygen generation, were also measured. The dyes were useful as photoinitiators for sensitizing compounds to photooxidation. Photoredox pairs comprising dyes and onium salts were found to be effective visible-wavelength initiators of free radical or cationic polymerization.     

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。     

6‐Pyridinium benzo[a]phenazine‐5‐oxide derivatives as visible photosensitisers for polymerisation

Several 6‐pyridinium benzo[a]phenazine‐5‐oxide derivatives have been synthesised and characterised by proton nuclear magnetic resonance spectroscopy and mass spectrometry. The spectroscopic and electrochemical properties of these dyes were examined. The dyes were used as reducible sensitisers for selected electron donors (phenylthioacetic acid, phenoxyacetic acid, N‐phenylglycine, and ethyl 4‐N,N‐dimethylaminobenzoate) and as oxidisable sensitisers for electron acceptors (onium and N‐alkoxypyridinium salts). These photoredox pairs were found to be effective visible‐wavelength photoinitiators for the free radical polymerisation of trimethylolpropane triacrylate under visible light. The cationic photopolymerisation of cyclohexene oxide by the studied dyes and the onium salt photoredox pairs was ineffective. The obtained results are discussed on the basis of both free energy change for electron transfer to or from the benzo[a]phenazine dyes and the photochemical properties of the dyes, particularly their photobleaching. The proposed mechanism of dye fading is supported by density functional theory calculations and spectroscopic characterisation of the radical cation of the dye.     

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.     

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。     

Photoinitiating systems for cationic photopolymerization: Ongoing push toward long wavelengths and low light intensities

Recently, long-wavelength photoinitiating systems for cationic photopolymerization (LWCPIs) have attracted growing interest due to the wide applications of visible light emission sources. The approaches used to expand the wavelength range of the cationic photoinitiating (CPI) system range from designing new onium salts with long-wavelength absorbing chromophores to photosensizing conventional onium salts with various visible light photosenzitizers or free radical sources. In this review, the initiating mechanisms and characteristics of each approach are introduced, and the latest developments are highlighted. Based on analysis and comparison of recent progress, forthcoming developments are proposed as well.     

Visible laser lights in photoinduced polymerization. VI. Thioxanthones and ketocoumarins as photoinitiators

The efficiency of thioxanthones and ketocoumarins as photoinitiators has been checked in visible laser light-induced polymerization reactions and discussed in terms of excited-state reactivity (as revealed by time-resolved laser spectroscopy). These compounds undergo fast electron transfer reaction in the presence of amines and onium salts. Transient absorption spectra and rate constants of the processes involved have been determined. The combination photoinitiator-amine-onium salt appears as very promising for the design of efficient photosensitive systems.     

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.     

Kationische Photopolymerisation von Isobutylglycidether mit Benzoinderivat/Aryloniumsalz- bzw. Benzildimethylketal/Aryloniumsalz-Initiatorsystemen

Cationic Photopolymerization of Isobutylglycidyl Ether with Benzoine Derivatives/Arylonium Salts- or Benzildimethyl Ketal/Arylonium Salts-Initiator Systems Radicals produced by photolysis of benzoine derivatives and benzile dimethylketale decompose arene diazonium salts (ArN₂⊕), diphenyliodonium salts (Ph₂I⊕) and triphenylsulfonium salts (Ph₃S⊕), respectively. The carbenium ions or protons formed in this way can be used for the cationic polymerization of isobutylglycidyl ether (IBGE). The efficiency of this polymerization depends on the quantum yields of the onium salts decomposition. A reactivity ArN₂⊕ > Ph₂I⊕ > Ph₃S⊕ was found. In the case of ArN₂⊕ the salt decomposition is caused by electron transfer between the photolytically produced substituted benzylic radicals and the diazonium ions. It is assumed that by the decomposition of Ph₂I⊕ and Ph₃S⊕ intermediates occur, which give rise to some reversible reactions. Therefore, the quantum yields of onium salt decomposition are less than those of initiator photolysis. The rate of cationic polymerization of IBGE is also influenced by the anion of onium compounds. A sequence PF₆⊖ >SbF₆⊖ >BF₄⊖ was found.