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。     

阳离子光固化聚硅氧烷的制备及性能研究

以二甲基二甲氧基硅烷、二苯基二甲氧基硅烷和3-(2,3-环氧丙氧)丙基甲基二乙氧基硅烷为原料,借助在四甲基氢氧化铵催化下的水解-缩聚反应,制得可阳离子光固化的环氧化苯基聚硅氧烷(EP-PMPS);再将EP-PMPS与不同阳离子光引发剂互配,研究了苯基、环氧基含量对其光聚合效率以及光固化制品性能的影响.结果 表明:所合成...     

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。     

辐照固化涂料进展（Ⅱ）

3 阳离子光固化体系 阳离子光固化体系的发展较自由基光固化体系为晚,因为阳离子的光固化反应是以阳离子聚合为基础的,而阳离子聚合通常要求在低温无水条件下进行,条件比自由基聚合苛刻。这种观念妨碍了阳离子光固化体系的发展。实际上光固化反应与聚合反应有很大不同,光固化反应不要求得到长链聚合物,尽管阳离子聚合在有水和高温下易于发生链终止,但链终止时仍可产生新的活性中心（质子或其它阳离子）,它们仍可和双键发生加成,引发新的反应,其链终止相当于链转移,并不影响多官能基单体、齐聚物间的交联反应,最终得到固化材料。阳离子固化体系有明显的优点如不怕氧气,固化时体积收缩问题可以得到控制。阳离子光固化体系和自由基光固化体系一样,分引发体系与树脂两部分。3.1 阳离子光引发体系     

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。     

新型紫外光固化大分子光引发剂的研究进展

综述了大分子光引发剂中改良型紫外光(UV)固化引发剂(有机硅、超支化聚合物改性)和新型UV固化引发剂(阳离子、可聚合和水性)在合成方法、结构性能等方面的最新研究进展。最后指出了大分子光引发剂仍存在的不足之处,并就其在阳离子-自由基混杂型、高Mr(相对分子质量)型及可见光型等方面的发展前景作了展望。     

阳离子淀粉复合絮凝剂对高岭土悬浮液的絮凝处理

以玉米淀粉和3-氯-2-羟丙基三甲基氯化铵(CTA)为原料,采用干法合成高取代度阳离子淀粉,并与聚合三氯化铝(PAC)复合来对高岭土悬浮液进行絮凝处理。考察了聚合三氯化铝和阳离子淀粉的质量配比、沉降时间以及pH对絮凝性能的影响。最佳絮凝条件ρ(阳离子淀粉)=5mg/L(高岭土悬浮液),m(PAC)∶m(阳离子淀粉)=10∶1,沉降时间为32min,pH=9。在此条件下,高岭土悬浮液的浊度可降至3.1。     

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。     

新型杂化光聚合体系

光固化方式的复合化是对光固化体系进行改性的重要方法。通过将自由基和阳离子以及阳离子和阳离子配合组成新的光固化体系,可以得到优良的固化体系。本论文以多种丙烯酸酯,乙烯基醚,环氧树脂,以及实验室合成的杂化单体等做为基础材料进行混合杂化光聚合体系,杂化单体光聚合体系的光固化动力学比较,并对羟基化合物对各体系的影响进行分析。实验结果表明,杂化单体在转化率,转化速度,对羟基化合物不敏感性等多方面都比混合杂化体系有明显优势。     

Visible light sensitive photoinitiating systems: Recent progress in cationic and radical photopolymerization reactions under soft conditions

Although there have been many reports on photoinitiating systems adapted to visible lights for radical photopolymerization, the challenge for the design and development of photoinitiating systems for cationic photopolymerization or concomitant radical/cationic photopolymerization (for interpenetrating polymer network IPN synthesis) with visible lights still remains open. Particularly, the recent development of cheap and easily accessible LEDs operating upon soft visible light irradiations has opened new fields for polymer synthesis. Since 2011, many novel photoinitiating systems based on organic and organometallic compounds with excellent visible light absorption have emerged and exhibited outstanding photoinitiating abilities especially for cationic photopolymerization. In this review, recent progress (mainly from 2011 to early 2014) in applications of photoinitiators and sensitive photoinitiating systems under visible lights are reported. In addition, their relative efficiencies in the photopolymerization of different monomers are exemplified and discussed.     

Kinetic study of photoinduced quasi-simultaneous interpenetrating polymer networks

Interpenetrating Polymer Networks (IPNs) based on a dimethacrylate and an epoxide are synthesized by photopolymerization. By varying the relative amount of radical photoinitiator with respect to the cationic one, and by changing the exposure conditions, it was found possible to delay or accelerate the photopolymerization of the methacrylate monomer compared to the epoxide one. The effect of the relative rate of photopolymerization on the final conversion, glass transition, and morphology is discussed. Finally, the increase in shear modulus as a function of irradiation time was investigated by real time ultrasonic reflectometry. An increase in the mechanical properties after the exposure was evidenced as a consequence of the living character of the cationic polymerization.     

A kinetic study of the acceleration effect of substituted benzyl alcohols on the cationic photopolymerization rate of epoxidized natural oils

The rate of the cationic photopolymerization of epoxidized natural oils was enhanced by the addition of several mono, di and trisubstituted benzyl alcohols. The epoxidation of vegetable oils was achieved by using 30% hydrogen peroxide with methyl trioxo rhenium (MTO) as a phase transfer catalyst. Then, the effect of different methoxy-substituted benzyl alcohols on the curing rate was evaluated, using the real-time FT-IR technique. The overall result was an increase in the curing rate. The acceleration effect was explained on the basis of synergistic effects of two mechanisms, namely, the radical induced cationic photopolymerization and the activated monomer mechanism. Epoxidized oils with 2,5-dimethoxybenzyl alcohol as an accelerator exhibited the highest photopolymerization rate. Higher conversions were obtained using electron-transfer photosensitizers.     

Study of epoxidized-cardanol containing cationic UV curable materials

Cationic photopolymerization, thermal and mechanical properties of thin film materials containing bio-renewable cashew nutshell oil derivative – epoxidized-cardanol (ECD) were investigated. Higher and more consistent monomer conversion as a function of relative humidity was found for thin film materials containing 10 wt.% ECD and 5 wt.% hydroxy-functional reactive diluents during cationic photopolymerization. In addition, ECD imparted balanced physiochemical properties to the cationic UV curable materials. ECD showed great potential to be used as a reactive ingredient in cationic UV curable materials.     

Synthesis of novel highly reactive silicone-epoxy monomers for cationic photopolymerizations

A series of novel cationically photopolymerizable silicone-epoxide monomers bearing substituted benzyl ether groups were prepared. Monomers with methoxy groups on the aromatic ring of the benzyl ether group were synthesized by sequential hydrosylation reactions of 1,1,3,3-tetramethyl disiloxane. Kinetic studies using real-time infrared spectroscopy of the cationic photopolymerizations of these novel monomers showed that those monomers with methoxy groups exhibited elevated rates of photopolymerization. The acceleration effect was explained on the basis of synergistic effects of two mechanisms, namely, the normal ring opening polymerization catalyzed by a Brönstead acid, and the cationic photopolymerization induced by the redox interaction between the free radicals formed in the backbone of the monomer and the onium salt used as photoinitiator. The methoxy groups on the aromatic ring of the benzyl ether enhance the stabilization of the carbocation formed in the structure of the monomer. Silicone-epoxy monomer with 2,5-dimethoxybenzyl ether group exhibited the higher photopolymerization rate. The latter compound can also be used as accelerator of the cationic photopolymerization of commercial silicone-epoxy monomer when used in low concentrations.     

Cationic photopolymerization of bisphenol-A-based vinyl ether systems

2,2-Bis{4-[2-(vinyloxy)ethoxy]phenyl}propane (BPA) monomer was synthesized and its cationic photopolymerization with triethyleneglycol divinyl-ether (DVE3) investigated. Real-time FT-IR kinetic investigations showed, in the presence of DVE3 monomer an increase of the photopolymerization rate and of the final vinyl ether double bond conversion.     

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     

Synthesis and photopolymerization of 4‐(1‐propenyl)oxybutyl acrylate

Hybrid monomer, 4‐(1‐propenyl)oxybutyl acrylate, with cationic and free radical polymerizable group was synthesized. Real‐time Fourier transform infrared spectroscopy (FTIR) was used to monitor the photopolymerization kinetics of the monomer. Photopolymerization processing conditions, such as light intensity, photoinitiator concentrations have been evaluated. It was found that hybrid monomer showed higher efficiency of photopolymerization in comparison with the blend system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008