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。     

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。     

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。     

紫外光固化涂料--液态光致抗蚀剂(Ⅱ)

４．３光引发剂的选择光引发剂包括光敏剂和助引发剂。后者虽不吸收光能，本身也不引发聚合，但可提高光引发剂的活化速率，所以亦称为光活化剂。光敏剂的选择原则应根据紫外光光源波长区域来定，由此选择的光敏剂才能发挥最大的效率。阳离子光引发剂在光照下可释出活性很强的阳离子，通常是H＋，因此也可以说是光照时释出强酸。阳离子和强酸可以引发一些烯类的单体如乙烯基醚聚合，也可使环氧化物开环聚合。最重要的阳离子引发剂是二苯碘盐和三苯硫盐，见图４。光解时，X－从其他物质如溶剂（用RH表示）中夺取一个氢，从而生成酸HX。单…     

辐射固化涂料

201004022无臭光固化涂料组合物,套印及其生产：适用于在电子照相印刷上形成套印涂层的光固化涂料组合物含阳离子可聚合含硅的聚合物、阳离子光聚合引发剂和阳离子可聚合化合物。     

光聚合现状与展望

本文叙述了自由基和阳离子聚合光引发剂体系的最新进展,并且提供了不同引发模式下在所有光引发体系中有关引发效率、波长限制和环境安全问题的解决办法。在过去10年里,通过光聚合制备了复杂或纳米结构的大分子,因此本文也介绍了光聚合在生物材料、表面改性和纳米复合材料领域的新兴应用。     

二苯基碘鎓氟硼酸盐引发AGE阳离子光聚合与光交联的研究

用合成的二苯基碘钅翁氟硼酸盐作为光敏引发剂 ,研究了含乙烯基和环氧基两种不同官能基的烯丙基缩水甘油醚 ( AGE)的阳离子光聚合和聚合前后微观结构的变化 ,讨论了其阳离子光聚合的特征和机理 ,测定了光聚合引起光交联的凝胶转化率曲线     

二苯基碘(钅翁)氟硼酸盐引发AGE阳离子光聚合与光交联的研究

用合成的二苯基碘(钅翁)氟硼酸盐作为光敏引发剂,研究了含乙烯基和环氧基两种不同官能基的烯丙基缩水甘油醚(AGE)的阳离子光聚合和聚合前后微观结构的变化,讨论了其阳离子光聚合的特征和机理,测定了光聚合引起光交联的凝胶转化率曲线.     

二苯基碘Weng氟硼酸盐引发AGE阳离子光聚合与光交联的研究

用合成的二苯基碘Ｗｅｎｇ硼酸盐作为光敏引发剂,研究了含乙烯基和环氧基两种不同官能基的烯丙基缩水甘油醚（ＡＧＥ）的阳离子光聚合前后微观结构的变化,讨论了其阳离子光聚合的特征和机理,测定了光聚合经起光交联的凝胶转化率曲线。     

夺氢型BCIM增感体系引发二甲基丙烯酸酯类单体的光聚合动力学

采用实时红外研究了聚乙二醇(400)二甲基丙烯酸酯和乙氧基化双酚A二甲基丙烯酸酯单体在复合光引发体系BCIM/EMK/NPG中的光聚合动力学.考察了复合光引发体系各组分的不同配比、光源、复合光引发体系浓度对两种单体的聚合动力学影响.结果表明:当BCIM、EMK、NPG质量比为2:1:1时,单体的聚合性能最好;两种单体的...     

不同官能度环氧树脂的阳离子光固化研究

对4种不同官能度的环氧树脂在紫外光辐照下用一种二苯基碘钅翁盐或两种二烷基苯甲酰锍盐光引发剂进行阳离子光固化的体系作了系统的研究。研究结果表明,二氨基二苯甲烷环氧树脂AG-80不能阳离子光固化,而E-51,711和TDE-85均可在二苯基碘钅翁六氟磷酸盐或1-甲基-1-十二烷基苯甲酰甲基六氟锑酸锍盐作用下进行紫外光引发阳离子聚合,其中二苯基碘钅翁六氟磷酸盐引发E-51环氧树脂阳离子光固化的效果最好,该树脂体系可用做紫外光固化复合材料的树脂基体。研究还发现,在停止紫外光辐照后,由于阳离子聚合链终止困难而使碘钅翁盐引发的环氧树脂光固化体系存在后固化现象,后固化速度与后固化时的温度有关。     

Photoactive epichlorohydrin, 2. Photoinitiated free-radical and promoted cationic polymerization by using polyepichlorohydrin with benzoin terminal groups

The photoinitiated free-radical polymerization of methyl methacrylate (MMA) and the radical-promoted cationic polymerization of cyclohexene oxide (CHO) in the presence of low-molecular-weight polyepichlorohydrin terminated with groups containing benzoin derivatives were studied. Benzoin-terminated polyepichlorohydrin was prepared by Activated Monomer (AM) polymerization. Upon photolysis. polymer-bound alkoxy benzyl radicals were generated, initiating the radical polymerization of MMA. In the case of radical-promoted cationic polymerization of CHO, the cationic initiating species were formed by the oxidation of photochemically generated polymeric radicals by N-ethoxy-2-methylpyridinium hexafluorophosphate.     

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.     

Renewable epoxy networks by photoinitiated copolymerization of poly(3-hydroxyalkanoate)s and isosorbide derivatives

New biodegradable epoxy networks derived from poly(3-hydroxyalkanoate)s and isosorbide were synthesized by photoinitiated cationic ring opening polymerization in the presence of diaryl iodonium salt (I 250). Bis-epoxidized terminated PHA oligomers, PHA-diepoxy, were first prepared in three steps, microwave assisted alcoholysis in the presence of ethylene glycol, condensation with allyl isocyanate and epoxidation of alkene terminal groups. Moreover, isosorbide diglycidyl ether (DGEDAS) was prepared by epoxidation of allylic derivative. The photoinitiated polymerization is a straightforward way applied at room temperature in a very short reaction time (i.e. 300 s) to obtain renewable crosslinked networks that remain partially biodegradable by lipase. Higher degradability was observed by increasing the content of PHA.     

Hybrid copolymerization of alkyl vinyl ethers with glycidyl ethers

Homopolymerization and copolymerization experiments of isobutyl and dodecyl vinyl ether with propylene oxide, and some glycidyl ethers have been carried out by using both conventional cationic initiators (BF₃, BF₃·OEt₂) and 4-chlorophenyldiazonium tetrafluoborate as cationic photoinitiator. Conventional polymerization experiments performed under vacuum at low and room temperature gave rise to a mixture of the two homopolymers, indicating that the epoxide and vinyl ethers are incompatible with respect to chemical reactivity and that apparently no hybrid copolymerization occurs. Analogous results were obtained in parallel photoinitiated polymerization experiments.     

紫外光引发乳液聚合制备P(St-co-MMA)复合微球

以十二烷基硫酸钠为乳化剂,2,2-二甲氧基-2-苯基苯乙酮等为引发剂,在水中由紫外光引发苯乙烯(St)和甲基丙烯酸甲酯(MMA)进行乳液聚合,研究了引发剂种类及乳化剂用量对反应收率和微球粒径的影响,并与光引发分散聚合体系进行了比较。结果表明,乳液聚合速率大于分散聚合,由乳液聚合得到的P(St-co-MMA)微球的粒径均一,可控制在70～140 nm之间。     

Photoinitiated graft polymerization of acrylamide to polyethylene terephthalate and properties of the modified fibres

Conclusions A study of the process of photoinitiated grafting of acrylamide to fibres of polyethylene terephthalate in the presence of benzophenone introduced into the fibre by preliminary treatment in a mixture of organic solvents indicates the possibility of carrying out a graft polymerization reaction without significant homopolymer formation.The modified fibre is characterized by an increased hydrophilicity and dyeability with cationic dyes, and by a good antistatic response. No impairment in breaking characteristics of the fibre or in its thermal properties takes place as a result of the grafting.Yugoslavia. Translated from Khimicheskie Volokna, No. 4, pp. 49–51, July–August, 1985.     

The synthesis and cationic polymerization of novel epoxide monomers

The preparation of a novel series of multifunctional silicon-containing epoxide monomers, oligomers, and polymers has been carried out. The hydrosilylation method employed was found to be applicable to the design and synthesis of a wide variety of materials with different chemical and mechanical characteristics, which range from hard and brittle to elastomeric. By tailoring the kinds of and number of epoxide groups that are incorporated into these materials, it is possible to substantially modify their reactivity in photoinitiated cationic polymerization. Those monomers and oligomers containing cycloaliphatic epoxide rings undergo polymerization rates considerably more rapid than conventional epoxides. There are many applications of such photocurable monomers in the field of electronic materials.