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。     

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。     

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。     

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。     

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.     

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。     

光致阳离子聚合引发剂的进展

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光致阳离子引发剂的种类、制备以及引发机理进行了综述。     

二茂铁四氟硼酸盐的阳离子光引发性能的研究

制备并研究了[CpFeCp]BF4作为阳离子光引发剂在高压汞灯下引发环氧类预聚物的光引发活性。发现其在紫外及可见光区均有较强吸收（λm=355nm、620nm)；对环氧类预聚物，具有优良的光引发活性，感度值可达41.8mJ/cm^2，优于其它的阳离子光引发剂；[CpFeCp]BF4的最佳使用浓度为3％（质量分数）左右，由于光照后仍有强后聚合活性，发现其在较低浓度（质量分数1％）引发后放置，仍可使聚合完全；同其它的阳离子光引发剂相比，[CpFeCp]BF4制备简单，非常有应用价值。     

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。     

侧基官能性乙烯基醚阳离子活性聚合与乙烯基醚阳离子光固化体系

本文着重介绍阳离子聚合单体的结构、溶剂及引发体系对活性阳离子聚合技术的影响以及近几年来采用活性阳离子聚合技术制备侧基官能性乙烯基醚聚合物的方法,尤其是应用较广泛的羟基、羧基、氨基等侧基官能化聚合物的合成。研究乙烯基醚阳离子活性聚合,将对乙烯基醚阳离子光固化体系的应用研究具有重要的指导意义。     

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。     

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.     

阳离子聚丙烯酰胺的聚合与应用研究进展

综述了近年来阳离子聚丙烯酰胺的聚合与应用研究进展,主要阐述了反相乳液聚合、双水相聚合、紫外光引发聚合以及模板聚合等聚合方法,介绍了阳离子聚丙烯酰胺在工业水处理、城市污废水处理、污泥脱水以及造纸工业中的应用,并对阳离子聚丙烯酰胺未来的发展趋势与研究方向进行了展望,为阳离子聚丙烯酰胺的进一步研究提供参考依据。     

Surface grafting of polymers onto ultrafine silica: cationic polymerization initiated by benzylium perchlorate groups introduced onto ultrafine silica surface

Summary The cationic graft polymerization initiated by benzylium perchlorate groups introduced onto ultrafine silica surface was investigated. The introduction of benzylium perchlorate groups onto the surface was achieved by the reaction of silver perchlorate with surface benzyl chloride groups, which were introduced by the treatment of silica with 4-(chloromethyl)phenyltrimethoxysilane. The cationic graft polymerization of styrene and cationic ring-opening polymerization of -caprolactone were found to be initiated by the surface benzylium perchlorate groups and the corresponding polymers were grafted onto the surface. The percentage of grafting onto silica surface decreased with increasing polymerization temperature, because chain transfer reaction of growing polymer cation is accelerated with increasing polymerization temperature.     

Modeling the emulsion polymerization of amino-functionalized latex particles

A mathematical model for a semicontinuous seeded cationic emulsion polymerization was developed. The model includes the most distinctive features of the copolymerization of a cationic hydrophilic monomer with a hydrophobic one, including polymerization of the hydrophilic monomer in the outer shell of polymer particles and in the aqueous phase, and the possibility of having radical concentration profiles in the polymer particles.The reactions were carried out by means of a semicontinuous seeded cationic emulsion polymerization under starved conditions for styrene, which was the main monomer employed.The model predicts the evolution of the fractional overall conversions, the thickness of the outer shell, the total surface charge density and the partial conversions for the semicontinuous seeded cationic emulsion polymerization of styrene and aminoethyl methacrylate hydrochloride. Furthermore, the model can distinguish between the surface charge density provided by the cationic monomer than that given by the cationic initiator. Therefore, this model can predict the best conditions to obtain well-defined latexes with specific amounts of surface amino and amidine groups useful for immunoassays.     

Cationic graft polymerization of polymers from carbon fiber initiated by acylium perchlorate groups introduced onto the surface

The cationic graft polymerization of several monomers initiated by acylium perchlorate groups introduced onto the carbon fiber surface was investigated to modify the surface. The introduction of acylium perchlorate groups was successfully achieved by the reaction of silver perchlorate with acyl chloride groups, which were introduced by the reaction of surface carboxyl groups with thionyl chloride. It was found that the cationic polymerization of styrene is initiated by acylium perchlorate groups on the carbon fiber. In the polymerization, polystyrene was grafted onto the carbon fiber surface through the propagation of polystyrene from the surface. Ungrafted polymer was also formed by the chain transfer reaction of growing polymer cation to the monomer. The acylium perchlorate groups have the ability to initiate cationic ring-opening polymerization of tetrahydrofuran (THF) and ε-caprolactone (CL), polyTHF and polyCL being grafted onto the carbon fiber surface, respectively. Polyacetals, such as poly(1,3-dioxolane) and polyoxymethylene, were able to graft onto the carbon fiber by cationic ring-opening polymerization of the corresponding monomers.