共查询到19条相似文献,搜索用时 625 毫秒
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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. 相似文献
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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。 相似文献
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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 相似文献
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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。 相似文献
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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。 相似文献
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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. 相似文献
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M. de Brito X. Allonas C. Croutxé-Barghorn M. Palmieri C. Dietlin S. Agarwal D. Lellinger I. Alig 《Progress in Organic Coatings》2012,73(2-3):186-193
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. 相似文献
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A kinetic study of the acceleration effect of substituted benzyl alcohols on the cationic photopolymerization rate of epoxidized natural oils 总被引:1,自引:0,他引:1
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. 相似文献
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Zhigang Chen Bret J. ChisholmDean C. Webster Ying ZhangSandeep Patel 《Progress in Organic Coatings》2009
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. 相似文献
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Synthesis of novel highly reactive silicone-epoxy monomers for cationic photopolymerizations 总被引:1,自引:0,他引:1
Ricardo Acosta Ortiz María de Lourdes Guillén Cisneros Graciela Arias García 《Polymer》2005,46(24):10663-10671
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. 相似文献
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E. Stanislovaityte A. Priola M. Sangermano G. Malucelli J. Simokaitiene R. Lazauskaite J.V. Grazulevicius 《Progress in Organic Coatings》2009
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. 相似文献
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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 相似文献
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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 kp[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 相似文献